<PAGE>

                                                                   Exhibit 10.50
                                   AGREEMENT

          This Agreement, which shall become effective as of the 1st day of
July, 1999, is entered into by and between ITC/\DeltaCom Communications, Inc.
("DeltaCom"), on behalf of Itself, and BellSouth Telecommunications, Inc.,
(BellSouth"), a Georgia corporation, having an office at 675 W. Peachtree
Street, Atlanta, Georgia, 30375, on behalf of itself and its successors and
assigns.

     WHEREAS, the Telecommunications Act of 1996 (the "Act") was signed into law
on February 8, 1996; and

     WHEREAS, section 252(j) of the Act requires BellSouth to make available any
interconnection, service, or network element provided under an agreement
approved by the appropriate state regulatory body to any other requesting
telecommunications carrier upon the same terms and conditions as those provided
in the agreement in its entirety; and

     WHEREAS, DeltaCom has requested that BellSouth make available the
interconnection agreement In its entirety executed between BellSouth and
MCImetro Access Transmission Services, Inc. ("MCIm") dated September 24, 1997
for the state of Mississippi.

     NOW, THEREFORE, in consideration of the promises and mutual covenants of
this Agreement, DeltaCom and BellSouth hereby agree as follows:

     1.  DeltaCom and BellSouth shall adopt In its entirety the Mississippi
MCIm/BellSouth Interconnection Agreement dated September 24, 1997 and any and
all amendments to said agreement executed and approved by the appropriate state
regulatory commission as of the date of the execution of this Agreement. The
Mississippi MClm/BellSouth Interconnection Agreement and all amendments are
attached hereto as Exhibit I and incorporated herein by this reference. The
adoption of this agreement with amendment(s) consists of the following:

<TABLE>
<CAPTION>

                                                                               NO.
ITEM                                                                         PAGES
-------------------------------------------------------------------------------------
<S>                                                                       <C>
Adoption Papers                                                                3
-------------------------------------------------------------------------------------
Title Page                                                                     1
-------------------------------------------------------------------------------------
Table of Contents                                                              1
-------------------------------------------------------------------------------------
General Terms and Conditions                                                  46
-------------------------------------------------------------------------------------
Attachment 1                                                                  11
-------------------------------------------------------------------------------------
Attachment 2                                                                  15
-------------------------------------------------------------------------------------
Attachment 3                                                                 103
-------------------------------------------------------------------------------------
Attachment 4                                                                  12
-------------------------------------------------------------------------------------
Attachment 5                                                                   9
--------------------------------------------------------------------------------------
Attachment 6                                                                  42
-------------------------------------------------------------------------------------
</TABLE>
<PAGE>

<TABLE>
<S>                                                                       <C>
-------------------------------------------------------------------------------------
Attachment 7                                                                  10
-------------------------------------------------------------------------------------
Attachment 8                                                                  98
-------------------------------------------------------------------------------------
Attachment 9                                                                   5
-------------------------------------------------------------------------------------
Attachment 10                                                                  1
-------------------------------------------------------------------------------------
Amendment dated 12/27/97                                                       4
-------------------------------------------------------------------------------------
Second Amendment dated 9/15/99                                                 2
-------------------------------------------------------------------------------------
TOTAL                                                                        363
-------------------------------------------------------------------------------------
</TABLE>

     2. In the event that DeltaCom consists of two (2) or more separate entities
as set forth in the preamble to this Agreement, all such entities shall be
Jointly and severally liable for the obligations of DeltaCom under this
Agreement.

     3. The term of this Agreement shall be from the effective date as set forth
above and shall expire as set forth in Section 3-General Terms and Conditions of
the Mississippi MCIm/BellSouth Interconnection Agreement. For the purposes of
determining the expiration date of this Agreement pursuant to Section 3-General
Terms and Conditions of the Mississippi MCIm/BellSouth Interconnection
Agreement, the effective date shall be September 24, 1997.

     4. DeltaCom shall accept and incorporate any amendments to the MCIm
Interconnection Agreement executed as a result of any final judicial,
regulatory, or legislative action.

     5. Every notice, consent, approval, or other communications required or
contemplated by this Agreement shall be in writing and shall be delivered in
person or given by postage prepaid mail, address to:


                BellSouth Telecommunications, Inc.

                DeltaCom Account Team
                9th Floor
                600 North 19th Street
                Birmingham, Alabama 35203

                and

                General Attorney - COU
                Suite 4300
                675 W. Peachtree St.
                Atlanta, GA 30375

                                       2
<PAGE>

                ITC/\DeltaCom Communications Inc.

                Senior Manager -- Industry Relations
                1530 DeltaCom Drive
                PO Box 787
                Anniston, AL 36202

                and

                Director -- Regulatory Affairs
                Suite 101
                700 Boulevard South
                Huntsville, AL 35802

or at such other address as the intended recipient previously shall have
designated by written notice to the other Party. Where specifically required,
notices shall be by certified or registered mail. Unless otherwise provided in
this Agreement, notice by mail shall be effective on the date it is officially
recorded as delivered by return receipt or equivalent, and In the absence of
such record of delivery, it shall be presumed to have been delivered the fifth
day, or next business day after the fifth day, after it was deposited in the
mails.

IN WITNESS WHEREOF, the Parties have executed this Agreement through their
authorized representatives.

BellSouthTelecommunications, Inc.       ITC/\DeltaCom Communications, Inc.



   /s/ Jerry D. Hendrix                   /s/ Christopher J. Rozycki
 ----------------------                 ----------------------------
 Signature                              Signature


   Jerry D. Hendrix                       Christopher J. Rozycki
 ------------------                     ------------------------
 Name                                   Name


   Sr. Director                           Director--Regulatory Affairs
 --------------                         ------------------------------
 Title                                  Title


   December 9, 1999                       December 2, 1999
 ------------------                     ------------------
 Date                                   Date


                                       3
<PAGE>

                                                                       Exhibit I

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  MCIMETRO/BELLSOUTH INTERCONNECTION AGREEMENT


This Interconnection Agreement (the "Agreement"), effective [insert date], 199__
(the "Effective Date"), is entered into by and between BellSouth
Telecommunications, Inc. ("BellSouth"), a Georgia corporation, and MCImetro
Access Transmission Services, Inc. ("MCIm"), a Delaware corporation, to
establish the rates, terms and conditions for interconnection, local resale,
ancillary services and purchase of unbundled network elements (individually
referred to as the "service" or collectively as the "services").

WHEREAS, the parties wish to interconnect their local exchange networks in a
technically and economically efficient manner for the transmission and
termination of calls ("Interconnection"); and

WHEREAS, MCIm wishes to purchase Telecommunications Services for resale to
others ("Local Resale" or "Services for Resale"), and BellSouth is willing to
provide such service pursuant to the terms and conditions of this Agreement; and

WHEREAS, MCIm wishes to purchase on an unbundled basis Network Elements, and
BellSouth is willing to provide such services; and

WHEREAS, MCIm wishes to purchase ancillary services such as access to poles,
ducts conduits and rights of way and collocation of equipment at BellSouth' s
facilities on the terms and subject to the conditions of this Agreement; and

WHEREAS, the parties intend the rates, terms and conditions of this Agreement,
and their performance of obligations thereunder, to comply with the
Communications Act of 1934, as amended by the Telecommunications Act of 1996
(the "Act"), the applicable Rules and Regulations of the Federal Communications
Commission ("FCC") in effect, and the orders, rules and regulations of the state
regulatory body.

Now, therefore, in consideration of the terms and conditions contained herein,
BellSouth and MCIm hereby mutually agree as follows:

                                                                      Part A - 1
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                                     PART A
                          GENERAL TERMS AND CONDITIONS

SECTION 1. SCOPE OF THIS AGREEMENT

         1.1 This Agreement, including Parts A, B, and C, specifies the rights
         and obligations of each party with respect to the purchase and sale of
         Interconnection, Local Resale, Network Elements and ancillary services.
         This PART A sets forth the general terms and conditions governing this
         Agreement. Certain terms used in this Agreement shall have the meanings
         defined in PART B -- DEFINITIONS, or as otherwise elsewhere defined
         throughout this Agreement. Other terms used but not defined herein will
         have the meanings ascribed to them in the Act and the applicable FCC
         Rules and Regulations in effect. PART C sets forth, among other things,
         descriptions of the services, pricing, technical and business
         requirements, and physical and network security requirements.

LIST OF ATTACHMENTS COMPRISING PART C:

I.    Price Schedule
II.   Local Resale
III.  Network Elements
IV.   Interconnection
V.    Collocation
VI.   Rights of Way
VII.  Number Portability
VIII. Business Process Requirements
IX.   Security Requirements
X.    Credits for Performance Standards Failures

         1.2 BellSouth shall provide the services pursuant to this Agreement.
         Except as provided below, BellSouth shall not discontinue or refuse to
         provide any service provided or required hereunder without MCIm's
         prior written agreement. Such agreement shall not be unreasonably
         withheld. BellSouth shall not discontinue any telecommunications
         service available for resale unless BellSouth provides MCIm prior
         written notice of its intent to discontinue any such service. BellSouth
         agrees to make any such service available to MCIm for resale to MCIm
         customers who are subscribers to such services from MCIm until the date
         BellSouth discontinues any such service for BellSouth's customers.
         BellSouth also agrees to adopt a reasonable, nondiscriminatory
         transition schedule for BellSouth and MCIm customers who may be
         purchasing any such service.

                  1.2.1 Left Blank Intentionally

                                                                      Part A - 2
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement


                  1.2.2 Left Blank Intentionally

SECTION 2. REGULATORY APPROVALS

         2.1 This Agreement, and any amendment or modification hereof, will be
         submitted to the state regulatory body for approval in accordance with
         Section 252 of the Act. Should the state regulatory body deny approval
         of the Agreement or any part thereof, the parties agree to consider
         whether any additional and appropriate judicial or administrative
         efforts are necessary to gain approval of said part or Agreement. If it
         is mutually determined that the part or Agreement must be renegotiated
         to gain approval by the state regulatory body, the parties agree to do
         so on an expedited basis. If the parties fail to reach agreement,
         either party may seek resolution pursuant to Section 23 (Dispute
         Resolution Procedures) of this Agreement.

         2.2 In the event the FCC or the State regulatory body promulgates rules
         or regulations, or issues orders, or a court with appropriate
         jurisdiction issues orders, which make unlawful any provision of this
         Agreement, the parties shall negotiate promptly and in good faith in
         order to amend the Agreement to substitute contract provisions which
         are consistent with such rules, regulations or orders. In the event the
         parties cannot agree on an amendment within thirty (30) days from the
         date any such rules, regulations or orders become effective, then the
         parties shall resolve their dispute under the applicable procedures set
         forth in Section 23 (Dispute Resolution Procedures) hereof.

         2.3 In the event BellSouth is required by any governmental authority to
         file a tariff or make another similar filing ("Filing") in order to
         implement this Agreement, BellSouth shall (i) consult with MCIm
         reasonably in advance of such Filing about the form and substance of
         such Filing, (ii) provide to MCIm its proposed tariff and obtain MCIm's
         agreement on the form and substance of such Filing, and (iii) take
         all steps reasonably necessary to ensure that such Filing imposes
         obligations upon BellSouth that are no less favorable than those
         provided in this Agreement and preserves for MCIm the full benefit of
         the rights otherwise provided in this Agreement. In no event shall
         BellSouth file any tariff to implement this Agreement that purports to
         govern the services provided hereunder that is inconsistent with the
         rates and other terms and conditions set forth in this Agreement unless
         such rate or other terms and conditions are more favorable than those
         set forth in this Agreement.

         2.4 In the event that any final and nonappealable legislative,
         regulatory, judicial or other legal action materially affects any
         material terms of this

                                                                      Part A - 3
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         Agreement, or the ability of MCIm or BellSouth to perform any material
         terms of this Agreement, or in the event a judicial or administrative
         stay of such action is not sought or granted, MCIm or BellSouth may, on
         thirty (30) days written notice (delivered not later than thirty (30)
         days following the date on which such action has become legally binding
         and has otherwise become final and nonappealable) require that such
         terms be renegotiated, and the Parties shall renegotiate in good faith
         such mutually acceptable new terms as may be required. In the event
         that such new terms are not renegotiated within ninety (90) days after
         such notice, the dispute shall be resolved in accordance with Section
         23 (Dispute Resolution Procedures) of this Agreement.

         2.5 The parties intend that any additional services requested by either
         party relating to the subject matter of this Agreement will be
         incorporated into this Agreement by amendment.

SECTION 3. TERM OF AGREEMENT

This Agreement shall become binding upon execution by the parties and continue
for a period of 3 years, unless earlier terminated in accordance with Section 20
(Termination). No later than 180 days prior to the expiration of this Agreement,
the parties agree to commence negotiations with regard to the terms, conditions
and prices of a follow on agreement for the provision of services to be
effective on or before the expiration date of this Agreement ("Follow-on
Agreement"). The Parties further agree that any such Follow-on Agreement shall
be for a term of no less than three years unless the Parties agree otherwise.

If, within 135 days of commencing the negotiation referenced above, the Parties
are unable to satisfactorily negotiate new terms, conditions and prices, either
Party may petition the State regulatory body to establish an appropriate
Follow-on Agreement pursuant to 47 U.S.C. Section 252. The Parties agree that in
such event they shall encourage the State regulatory body to issue its order
regarding such Follow-on Agreement no later than the expiration date of this
Agreement. The Parties further agree that in the event the State regulatory body
does not issue its order by the expiration date of this Agreement or if the
Parties continue beyond the expiration date of this Agreement to negotiate
without State regulatory body intervention, the terms, conditions and prices
ultimately ordered by the State regulatory body, or negotiated by the Parties,
will be effective retroactive to the day following the expiration date of this
Agreement. Until the Follow-on Agreement becomes effective, BellSouth shall
provide Services pursuant to the terms, conditions and prices of this Agreement
that are then in effect.

SECTION 4. CHARGES AND PAYMENT

                                                                      Part A - 4
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement


In consideration of the services provided by BellSouth under this Agreement,
MCIm shall pay the charges set forth in Attachment I. The billing and payment
procedures for charges incurred by MCIm hereunder are set forth in Attachment
VIII.

SECTION 5. ASSIGNMENT AND SUBCONTRACT

         5.1 Any assignment by either party to any non-affiliated entity of any
         right, obligation or duty, or of any other interest hereunder, in whole
         or in part, without the prior written consent of the other party shall
         be void. A party may assign this Agreement or any right, obligation,
         duty or other interest hereunder to an Affiliate company of the party
         without the consent of the other party. All obligations and duties of
         any party under this Agreement shall be binding on all successors in
         interest and assigns of such party. No assignment or delegation hereof
         shall relieve the assignor of its obligations under this Agreement in
         the event that the assignee fails to perform such obligations.

         5.2 If any party's obligation under this Agreement is performed by a
         subcontractor or affiliate, the Party subcontracting the obligation
         nevertheless shall remain fully responsible for the performance of this
         Agreement in accordance with its terms, and shall be solely responsible
         for payments due its subcontractors or affiliates. No subcontractor or
         affiliate shall be deemed a third party beneficiary for any purposes
         under this Agreement.

SECTION 6. COMPLIANCE WITH LAWS

All terms, conditions and operations under this Agreement shall be performed in
accordance with all applicable laws, regulations and judicial or regulatory
decisions of all duly constituted governmental authorities with appropriate
jurisdiction, and this Agreement shall be implemented consistent with the
applicable rules and regulations of the FCC and the state regulatory body in
effect. Each party shall be responsible for obtaining and keeping in effect all
FCC, state Commission, franchise authority and other regulatory approvals that
may be required in connection with the performance of its obligations under this
Agreement. In the event the basis for this Agreement (e.g., the Act, FCC Rules
and Regulations, orders of the state regulatory body) is held to be invalid or
changed for any reason, this Agreement shall survive, and the parties shall
promptly renegotiate any provisions of this Agreement, which in the absence of
such invalidated or changed Act, Rule or Regulation are insufficiently clear to
be effectuated.

SECTION 7. GOVERNING LAW

                                                                      Part A - 5
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement


This Agreement shall be governed by and construed in accordance with applicable
federal law and the laws of the state of Mississippi, without regard to its
conflicts of laws principles.

SECTION 8. RELATIONSHIP OF PARTIES

Each party is an independent contractor, and has and hereby retains the right to
exercise full control of and supervision over its own performance of its
obligations under this Agreement and retains full control over the employment,
direction, compensation and discharge of all employees assisting in the
performance of such obligations.

SECTION 9. NO THIRD PARTY BENEFICIARIES

The provisions of this Agreement are for the benefit of the parties hereto and
not for any other person. This Agreement shall not provide any person not a
party hereto with any remedy, claim, liability, reimbursement, claim of action,
or other right in excess of those existing without reference hereto.

SECTION 10. INTELLECTUAL PROPERTY RIGHTS AND INDEMNIFICATION

         10.1 Any intellectual property which originates from or is developed by
         a party shall remain in the exclusive ownership of that party. Except
         for a limited license to use patents or copyrights to the extent
         necessary for the parties to use any facilities or equipment (including
         software) or to receive any service solely as provided under this
         Agreement, no license in patent, copyright, trademark or trade secret,
         or other proprietary or intellectual property right now or hereafter
         owned, controlled or licensable by a party, is granted to the other
         party or shall be implied or arise by estoppel. It is the
         responsibility of each party to ensure at no additional cost to the
         other party that it has obtained any necessary licenses in relation to
         intellectual property of third parties used in its network that may be
         required to enable the other party to use any facilities or equipment
         (including software), to receive any service, or to perform its
         respective obligations under this Agreement.

         10.2 The party providing a service pursuant to this Agreement will
         defend the party receiving such service or data provided as a result of
         such service against claims of infringement arising solely from the use
         by the receiving party of such service and will indemnify the receiving
         party for any damages awarded based solely on such claims in accordance
         with Section 11 of this Agreement.

         10.3 In the event that use of any facilities or equipment (including

                                                                      Part A - 6
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         software), becomes or, in reasonable judgment of the party who owns the
         affected network is likely to become, the subject of a claim, action,
         suit, or proceeding based on intellectual property infringement, then
         said party shall promptly and at its sole expense, but subject to the
         limitations of liability set forth below:

                  (i) modify or replace the applicable facilities or equipment
                  (including software) while maintaining form and function, or
                  (ii) obtain a license sufficient to allow such use to
                  continue. In the event (i) or (ii) are commercially
                  unreasonable, then said party may, (iii) terminate, upon
                  reasonable notice, this contract with respect to use of, or
                  services provided through use of, the affected facilities or
                  equipment (including software), but solely to the extent
                  required to avoid the infringement claim.

         10.4 Neither party's obligations under this Section shall apply to the
         extent the infringement is caused by: (i) modification of the
         facilities or equipment (including software) by the indemnitee; (ii)
         use by the indemnitee of the facilities or equipment (including
         software) in combination with equipment or facilities (including
         software) not provided or authorized by the indemnitor provided the
         facilities or equipment (including software) would not be infringing if
         used alone; (iii) conformance to specifications of the indemnitee which
         would necessarily result in infringement; or (iv) continued use by the
         indemnitee of the affected facilities or equipment (including software)
         after being placed on notice to discontinue use as set forth herein.

         10.5 The foregoing shall constitute the parties' sole and exclusive
         remedies and obligations with respect to a third party claim of
         intellectual property infringement arising out of the conduct of
         business under this Agreement.

SECTION 11. LIMITATION OF LIABILITY AND INDEMNIFICATION

         11.1. Liability Cap.

                  11.1.1 With respect to any claim or suit, whether based in
                  contract, tort or any other theory of legal liability, by
                  MCIm, any MCIm customer or by any other person or entity, for
                  damages associated with any of the services provided by
                  BellSouth pursuant to or in connection with this Agreement,
                  including but not limited to the installation, provision,
                  preemption, termination, maintenance, repair or restoration of
                  service, and subject to the provisions of the remainder of
                  this Section, BellSouth's liability shall be limited to an
                  amount equal to the proportionate charge for the service
                  provided

                                                                      Part A - 7
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  pursuant to this Agreement for the period during which the
                  service was affected. Notwithstanding the foregoing, claims
                  for damages by MCIm, any MCIm customer or any other person or
                  entity resulting from the gross negligence or willful
                  misconduct of BellSouth and claims for damages by MCIm
                  resulting from the failure of BellSouth to honor in one or
                  more material respects any one or more of the material
                  provisions of this Agreement shall not be subject to such
                  limitation of liability.

                  11.1.2 With respect to any claim or suit, whether based in
                  contract, tort or any other theory of legal liability, by
                  BellSouth, any BellSouth customer or by any other person or
                  entity, for damages associated with any of the services
                  provided by MCIm pursuant to or in connection with this
                  Agreement, including but not limited to the installation,
                  provision, preemption, termination, maintenance, repair or
                  restoration of service, and subject to the provisions of the
                  remainder of this Section, MCIm's liability shall be limited
                  to an amount equal to the proportionate charge for the service
                  provided pursuant to this Agreement for the period during
                  which the service was affected. Notwithstanding the foregoing,
                  claims for damages by BellSouth, any BellSouth customer or any
                  other person or entity resulting from the gross negligence or
                  willful misconduct of MCIm and claims for damages by BellSouth
                  resulting from the failure of MCIm to honor in one or more
                  material respects any one or more of the material provisions
                  of this Agreement shall not be subject to such limitation of
                  liability.

         11.2 Neither party shall be liable for any act or omission of any other
         telecommunications company to the extent such other telecommunications
         company provides a portion of a service.

         11.3 Neither party shall be liable for damages to the other party's
         terminal location, Interconnection Point or the other party's
         customers' premises resulting from the furnishing of a service,
         including but not limited to the installation and removal of equipment
         and associated wiring, except to the extent the damage is caused by
         such party's gross negligence or willful misconduct.

         11.4 NO CONSEQUENTIAL DAMAGES - Neither MCIm nor BellSouth shall be
         liable to the other party for any indirect, incidental, consequential,
         reliance, or special damages suffered by such other party (including
         without limitation damages for harm to business, lost revenues, lost
         savings, or lost profits suffered by such other parties), regardless of
         the form of action, whether in contract, warranty, strict liability, or
         tort, including without limitation negligence of any kind whether
         active or

                                                                      Part A - 8
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         passive, and regardless of whether the parties knew of the possibility
         that such damages could result. Each party hereby releases the other
         party and such other party's subsidiaries and affiliates, and their
         respective officers, directors, employees and agents from any such
         claim. Nothing contained in this section 11 shall limit BellSouth's or
         MCIm's liability to the other for (i) willful or intentional misconduct
         (including gross negligence); (ii) bodily injury, death or damage to
         tangible real or tangible personal property proximately caused by
         BellSouth's or MCIm's negligent act or omission or that of their
         respective agents, subcontractors or employees, nor shall anything
         contained in this section 11 limit the parties' indemnification
         obligations as specified herein.

         11.5 OBLIGATION TO INDEMNIFY - Each Party shall, and hereby agrees to,
         defend at the other's request, indemnify and hold harmless the other
         Party and each of its officers, directors, employees and agents (each,
         an "Indemnitee") against and in respect of any loss, debt, liability,
         damage, obligation, claim, demand, judgment or settlement of any nature
         or kind, known or unknown, liquidated or unliquidated, including
         without limitation all reasonable costs and expenses incurred (legal,
         accounting or otherwise) (collectively, "Damages") arising out of,
         resulting from or based upon any pending or threatened claim, action,
         proceeding or suit by any third Party (a "Claim") (i) alleging any
         breach of any representation, warranty or covenant made by such
         indemnifying Party (the "Indemnifying Party") in this Agreement, (ii)
         based upon injuries or damage to any person or property or the
         environment arising out of or in connection with this Agreement that
         are the result of the Indemnifying Party's actions, breach of
         Applicable Law, or status of its employees, agents and subcontractors,
         or (iii) for actual or alleged infringement of any patent, copyright,
         trademark, service mark, trade name, trade dress, trade secret or any
         other intellectual property right, now known or later developed
         (referred to as "Intellectual Property Rights") to the extent that such
         claim or action arises from MCIm or MCIm's Customer's use of the
         Services and Elements provided under this Agreement.

         11.6 OBLIGATION TO DEFEND; NOTICE; COOPERATION - Whenever a Claim shall
         arise for indemnification under this Section 11, the relevant
         Indemnitee, as appropriate, shall promptly notify the Indemnifying
         Party and request the Indemnifying Party to defend the same. Failure to
         so notify the Indemnifying Party shall not relieve the Indemnifying
         Party of any liability that the Indemnifying Party might have, except
         to the extent that such failure prejudices the Indemnifying Party's
         ability to defend such Claim. The Indemnifying Party shall have the
         right to defend against such liability or assertion in which event the
         Indemnifying Party shall give written notice to the Indemnitee of
         acceptance of the defense of such

                                                                      Part A - 9
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         Claim and the identity of counsel selected by the Indemnifying Party.
         Except as set forth below, such notice to the relevant Indemnitee shall
         give the Indemnifying Party full authority to defend, adjust,
         compromise or settle such Claim with respect to which such notice shall
         have been given, except to the extent that any compromise or settlement
         shall prejudice the Intellectual Property Rights of the relevant
         Indemnitees. The Indemnifying Party shall consult with the relevant
         Indemnitee prior to any compromise or settlement that would affect the
         Intellectual Property Rights or other rights of any Indemnitee, and the
         relevant Indemnitee shall have the right to refuse such compromise or
         settlement and, at the refusing Party's or refusing Parties' cost, to
         take over such defense, provided that in such event the Indemnifying
         Party shall not be responsible for, nor shall it be obligated to
         indemnify the relevant Indemnitee against, any cost or liability in
         excess of such refused compromise or settlement. With respect to any
         defense accepted by the Indemnifying Party, the relevant Indemnitee
         shall be entitled to participate with the Indemnifying Party in such
         defense if the Claim requests equitable relief or other relief that
         could affect the rights of the Indemnitee and also shall be entitled to
         employ separate counsel for such defense at such Indemnitee's expense.
         In the event the Indemnifying Party does not accept the defense of any
         indemnified Claim as provided above, the relevant Indemnitee shall have
         the right to employ counsel for such defense at the expense of the
         Indemnifying Party. Each Party agrees to cooperate and to cause its
         employees and agents to cooperate with the other Party in the defense
         of any such Claim and the relevant records of each Party shall be
         available to the other Party with respect to any such defense.

         11.7 Both parties agree that they, at their own cost and expense, shall
         maintain throughout the term of this Agreement, all insurance required
         by law, and may at their own cost and expense purchase insurance or
         self-insure their employer, public, professional and legal liabilities.
         No limit of liability on any policy, not program of self-insurance, nor
         any failure to maintain adequate insurance coverage shall limit the
         direct or indirect liability of either party.

SECTION 12. Left blank intentionally

SECTION 13. CONTINUING OBLIGATIONS

         13.1 Except as otherwise provided herein, each party shall perform its
         obligations hereunder at a performance level no less than the level
         which it uses for its own operations, or those of its Affiliates, but
         in no event shall a party use less than reasonable care in the
         performance of its

                                                                     Part A - 10
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         duties hereunder.

                  13.1.1 In providing Services and Elements, BellSouth will
                  provide MCIm with the quality of service BellSouth provides
                  itself and its end-users. BellSouth's performance under this
                  Agreement shall provide MCIm with the capability to meet
                  standards or other measurements that are at least equal to the
                  level that BellSouth provides or is required to provide by law
                  and its own internal procedures. BellSouth shall satisfy all
                  service standards, measurements, and performance requirements
                  set forth in the Agreement and the measurements specified in
                  Section 13.4.2.25 of Attachment III and in Sections 2.5, 3.4,
                  4.4 - 4.5, and 5.4 of Attachment VIII of this Agreement. Any
                  conflict between the standards, measurements, and performance
                  requirements BellSouth provides itself and the standards,
                  measurements and performance requirements set forth in this
                  Agreement shall be resolved in favor of the higher standard,
                  measurement and performance.

                  13.1.2 The Parties acknowledge that the need will arise for
                  changes to the measurements specified in this Agreement during
                  the term of this Agreement. Such changes may include the
                  addition or deletion of measurements or a change in the
                  performance standard for any particular metric, as well as the
                  provision of target performance levels, as set forth in this
                  Agreement. Unless otherwise specified in this Agreement, the
                  Parties agree to review all measurements on a quarterly basis
                  to determine if any changes are appropriate, and may include
                  the provision to MCIm of any additional measurements BellSouth
                  may provide itself.

                  13.1.3 The Parties agree to monitor actual performance on a
                  monthly basis and, if the Parties conclude it is required,
                  develop a process improvement plan to improve quality of
                  service provided as measured by the performance measurements,
                  if necessary. Such a plan shall be developed where BellSouth's
                  performance falls below either the level of performance it
                  provides itself or the level of performance required in this
                  Agreement.

         13.2 BellSouth agrees that Interconnection will be provided in a
         competitively neutral fashion, at any technically feasible point within
         its network as stated in this Agreement and that such interconnection
         will contain all the same features, functions and capabilities, and be
         at least equal in quality to the level provided by BellSouth to itself
         or its Affiliates.

                                                                     Part A - 11
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            MCImetro-BellSouth Mississippi Interconnection Agreement

         13.3 BellSouth agrees that it will provide to MCIm on a
         nondiscriminatory basis unbundled Network Elements and ancillary
         services as set forth in this Agreement and the operations support
         systems as set forth in this Agreement. BellSouth further agrees that
         these services, or their functional components, will contain all the
         same features, functions and capabilities and be provided at a level of
         quality at least equal to the level which it provides to itself or its
         Affiliates.

         13.4. BellSouth agrees that it will provide to MCIm nondiscriminatory
         access to, poles, ducts, conduits, and rights of way owned or
         controlled by BellSouth in accordance with the requirements of Section
         224 of the Act.

         13.5 BellSouth Agrees that it will provide nondiscriminatory access to
         telephone numbers for as long as BellSouth remains the code
         administrator for the North American Numbering Plan.

         13.6 BellSouth agrees that it will provide to MCIm, in a competitively
         neutral fashion, interim number portability as set forth herein and in
         accordance with the applicable rules, regulations and orders of the FCC
         and this Commission, including the First Report and Order, released
         July 2, 1996 in CC Docket No. 95-116, regarding Telephone Number
         Portability, in effect.

         13.7 BellSouth agrees that it will provide to MCIm, in a competitively
         neutral fashion, dialing parity for local exchange service and
         interexchange service pursuant to the applicable rules, regulations and
         orders of the state regulatory body and the FCC in effect.

         13.8 BellSouth agrees that order entry, provisioning, installation,
         trouble resolution, maintenance, billing, and service quality with
         respect to Local Resale will be provided at least as expeditiously as
         BellSouth provides for itself or for its own retail local service or to
         others, or to its Affiliates, and that it will provide such services to
         MCIm in a competitively neutral fashion.

         13.9 BellSouth agrees that it will provide on a nondiscriminatory basis
         space on its premises for physical or virtual collocation, as MCIm may
         specify, for equipment necessary for MCIm's interconnection and access
         to unbundled network elements.

SECTION 14. NOTICES

Except as otherwise provided herein, all notices or other communication
hereunder shall be deemed to have been duly given when made in writing and

                                                                     Part A - 12
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

delivered in person by overnight courier, or deposited in the United States
mail, certified mail, postage prepaid, return receipt requested and addressed as
follows:

To MCIm:          MCImetro Access Transmission Services, Inc.
                  8521 Leesburg Pike
                  Vienna, VA 22182

Copy to:          General Counsel
                  MCI Communications Corporation
                  1801 Pennsylvania Ave, N.W.
                  Washington, DC 20006

To BellSouth:     Clifford H. Bowers
                  BellSouth Telecommunications, Inc.
                  1960 W. Exchange Pl., Ste. 402
                  Tucker, GA 30084

Copy to:          General Attorney-Interconnection
                  BellSouth Telecommunications, Inc.
                  Suite 4300
                  675 W. Peachtree Street, NE
                  Atlanta, Georgia 30375

If personal delivery or courier is selected to give notice, a receipt of such
delivery shall be obtained. The address to which notices or communications may
be given to either party may be changed by written notice given by such party to
the other pursuant to this Section 14.

SECTION 15. REMEDIES

         15.1 The obligations of BellSouth and the services offered under this
         Agreement are unique. Accordingly, in addition to any other available
         rights or remedies, MCIm may sue in equity for specific performance.

         15.2 Left blank intentionally

         15.3 All rights of termination, cancellation or other remedies
         prescribed in this Agreement, or otherwise available, are cumulative
         and are not intended to be exclusive of other remedies to which the
         injured party may be entitled at law or equity in case of any breach or
         threatened breach by the other party of any provision of this
         Agreement. Use of one or more remedies shall not bar use of any other
         remedy for the purpose of enforcing the provisions of this Agreement.

                                                                     Part A - 13
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            MCImetro-BellSouth Mississippi Interconnection Agreement


SECTION 16. WAIVERS

         16.1 No waiver of any provisions of this Agreement and no consent to
         any default under this Agreement shall be effective unless the same
         shall be in writing and properly executed by or on behalf of the party
         against whom such waiver or consent is claimed.

         16.2 No course of dealing or failure of any party to strictly enforce
         any term, right, or condition of this Agreement in any instance shall
         be construed as a general waiver or relinquishment of such term, right
         or condition.

         16.3 Waiver by either party of any default by the other party shall not
         be deemed a waiver of any other default.

SECTION 17. SURVIVAL

The following provisions of this Part A shall survive the expiration or
termination of this Agreement: Sections 10, 11, 12, 21, 22, 26 and 27, and any
other obligations to be performed after the expiration or termination of the
Agreement.

SECTION 18. FORCE MAJEURE

Neither party shall be held liable for any delay or failure in performance of
any part of this Agreement from any cause beyond its control and without its
fault or negligence, such as acts of God, acts of civil or military authority,
embargoes, epidemics, war, terrorist acts, riots, insurrections, fires,
explosions, earthquakes, strikes, nuclear accidents, floods, power blackouts, or
unusually severe weather. In the event of any such excused delay in the
performance of a party's obligations(s) under this Agreement, the due date for
the performance of the original obligation(s) shall be extended by a term equal
to the time lost by reason of delay. In the event of such delay, the delaying
party shall perform its obligations at a performance level no less than that
which it uses for its own operations and will resume performance in a
nondiscriminatory manner.

SECTION 19. NON-DISCRIMINATORY TREATMENT

If as a result of any proceeding or filing before any Court, State Commission,
or the Federal Communications Commission, voluntary agreement or arbitration
proceeding pursuant to the Act or pursuant to any applicable state law,
BellSouth becomes obligated to provide Services and Elements, whether or not
presently covered by this Agreement, to a third Party at rates or on terms and
conditions more favorable to such third Party than the applicable provisions of
this Agreement, MCIm shall have the option to substitute such more favorable

                                                                     Part A - 14
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            MCImetro-BellSouth Mississippi Interconnection Agreement

rates, terms, and conditions for the relevant provisions of this Agreement which
shall apply to the same States as such other Party, and such substituted rates,
terms or conditions shall be deemed to have been effective under this Agreement
as of the effective date thereof. BellSouth shall provide to MCIm any BellSouth
agreement between BellSouth and any third Party within fifteen (15) days of the
filing of such agreement with any state Commission.

SECTION 20. TERMINATION

         20.1 In the event of breach of any material provision of this Agreement
         by either party, the non-breaching party shall give the other party
         written notice thereof, and:

                  20.1.1 If such material breach is for non-payment of amounts
                  due hereunder pursuant to Attachment VIII, Section 3.1.18, the
                  breaching party shall cure such breach within thirty (30) days
                  of receiving such notice. The non-breaching party shall be
                  entitled to pursue all available legal and equitable remedies
                  for such breach. Amounts disputed in good faith and withheld
                  or set off shall not be deemed "amounts due hereunder" for the
                  purpose of this provision.

                  20.1.2 If such material breach is for any failure to perform
                  in accordance with this Agreement, which adversely affects the
                  non-breaching party's subscribers, the non-breaching party
                  shall give notice of the breach and the breaching party shall
                  cure such breach to the non-breaching party's reasonable
                  satisfaction within ten (10) business days, and if breaching
                  party does not, the non-breaching party may, at its sole
                  option, terminate this Agreement, or any parts hereof. The
                  non-breaching party shall be entitled to pursue all available
                  legal and equitable remedies for such breach. Notice under
                  this Subsection 20.1.2 may be given electronically or by
                  facsimile and in such case shall be deemed received when sent.

                  20.1.3 If such material breach is for any other failure to
                  perform in accordance with this Agreement, the breaching party
                  shall cure such breach to the non-breaching party's
                  reasonable satisfaction within forty-five (45) days, and if it
                  does not, the non-breaching party may, at is sole option
                  terminate this Agreement, or any parts hereof. The
                  non-breaching party shall be entitled to pursue all available
                  legal and equitable remedies for such breach.

                                                                     Part A - 15
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            MCImetro-BellSouth Mississippi Interconnection Agreement

         20.2 MCIm may terminate any Services provided under this Agreement upon
         thirty (30) days written notice to BellSouth unless a different notice
         period or different conditions are specified for termination of such
         Services in this Agreement, or pursuant to any applicable tariff, in
         which event such specific period or conditions shall apply. Where there
         is no such different notice period or different condition specified,
         MCIm's liability shall be limited to payment of the amounts due for any
         terminated Local Service(s), Network Element(s), Combination(s), or
         ancillary service(s) provided up to and including the date of
         termination. Notwithstanding the foregoing, the provisions of section
         11, supra, shall still apply. Upon termination, BellSouth agrees to
         cooperate in an orderly and efficient transition to MCIm or another
         vendor such that the level and quality of the services and Elements is
         not degraded and to exercise its best efforts to effect an orderly and
         efficient transition. MCIm agrees that it may not terminate the entire
         Agreement pursuant to this section.

SECTION 21. CONFIDENTIALITY AND PUBLICITY

         21.1 All confidential or proprietary information disclosed by either
         party during the negotiations and the term of this Agreement shall be
         protected by the parties in accordance with the terms of this Section
         21. All information which is disclosed by one party ("Disclosing
         Party") to the other ("Recipient") in connection with this Agreement,
         or acquired in the course of performance of this Agreement, shall be
         deemed confidential and proprietary to the Disclosing Party and subject
         to this Agreement, such information including but not limited to,
         orders for services, usage information in any form, and Customer
         Proprietary Network Information ("CPNI") as that term is defined by the
         Act and the rules and regulations of the FCC ("Confidential
         Information").

                  21.1.1 For a period of eight (8) years from receipt of
                  Confidential Information, Recipient shall (i) use it only for
                  the purpose of performing under this Agreement, (ii) hold it
                  in confidence and disclose it only to employees who have a
                  need to know it in order to perform under this Agreement, and
                  (iii) safeguard it from unauthorized use of Disclosure using
                  no less than the degree of care with which Recipient
                  safeguards it own Confidential Information. If Recipient
                  wishes to disclose the Discloser's Confidential Information
                  to a third party agent or consultant in order to perform
                  Recipient' s obligations hereunder, such third party must have
                  executed a written agreement comparable in scope to the terms
                  of this Section 21.

                  21.1.2 Recipient shall have no obligation to safeguard
                  Confidential Information (i) which was in the Recipient's
                  possession free of

                                                                     Part A - 16
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  restriction prior to its receipt from Disclosing Party, (ii)
                  which becomes publicly known or available through no breach of
                  this Agreement by Recipient, (iii) which is rightfully
                  acquired by Recipient free of restrictions on its Disclosure,
                  or (iv) which is independently developed by personnel of
                  Recipient to whom the Disclosing Party's Confidential
                  Information had not been previously disclosed. Recipient may
                  disclose Confidential Information if required by law, a court,
                  or governmental agency, provided that Disclosing Party has
                  been notified of the requirement promptly after Recipient
                  becomes aware of the requirement, and provided that Recipient
                  undertakes all lawful measures to avoid disclosing such
                  information until Disclosing Party has had reasonable time to
                  obtain a protective order. Recipient agrees to comply with any
                  protective order that covers the Confidential Information to
                  be disclosed.

                  21.1.3 Each party agrees that Disclosing Party would be
                  irreparably injured by a breach of this Section 21 by
                  Recipient or its representatives and that Disclosing Party
                  shall be entitled to seek equitable relief, including
                  injunctive relief and specific performance, in the event of
                  any breach of this Section 21. Such remedies shall not be
                  exclusive, but shall be in addition to all other remedies
                  available at law or in equity.

         21.2 CPNI related to MCIm's  subscribers obtained by virtue of Local
         Interconnection or any other service provided under this Agreement
         shall be MCIm's proprietary information and may not be used by
         BellSouth for any purpose except performance of its obligations under
         this Agreement, and in connection with such performance, shall be
         disclosed only to employees with a need to know, unless the MCIm
         subscriber expressly directs MCIm to disclose such information to
         BellSouth pursuant to the requirements of Section 222(c)(2) of the Act.
         In the event such authorization is obtained, BellSouth may use or
         disclose only such information as MCIm provides pursuant to such
         authorization and may not use information that BellSouth has otherwise
         obtained, directly or indirectly, in connection with its performance
         under this Agreement. CPNI related to BellSouth's subscribers obtained
         by virtue of Local Interconnection shall be BellSouth's proprietary
         information and may not be used by MCIm for any purpose except
         performance of its obligations under this Agreement, and in connection
         with such performance shall be disclosed only to employees with a need
         to know, unless the BellSouth subscriber expressly directs BellSouth to
         disclose such information to MCIm pursuant to the requirements of
         Section 222(c)(2) of the Act. In the event such authorization is
         obtained, MCIm may use or disclose only such information as BellSouth
         provides pursuant to such authorization and may

                                                                     Part A - 17
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         not use information that MCIm has otherwise obtained, directly or
         indirectly, in connection with its performance under this Agreement.

         21.3 Unless otherwise mutually agreed upon, neither party shall publish
         or use the other party's logo, trademark, service mark, name,
         language, pictures, or symbols or words from which the other party's
         name may reasonably be inferred or implied in any product, service,
         advertisement, promotion, or any other publicity matter.

         21.4 Neither party shall produce, publish or distribute any press
         release or other publicity referring to the other party or its
         Affiliates, or announcing the execution or discussing the terms of this
         Agreement without prior notice to the other party. In no event shall
         either party mischaracterize the contents of this Agreement in any
         public statement or in any representation to a governmental entity or
         member thereof.

         21.5 Except as otherwise expressly provided in this Section 21, nothing
         herein shall be construed as limiting the rights of either party with
         respect to its customer information under any applicable law, including
         without limitation Section 222 of the Act.

SECTION 22. AUDITS AND INSPECTIONS

         22.1 The following audit procedures shall apply.


                  22.1.1 Subject to BellSouth's reasonable security
                  requirements and except as may be otherwise specifically
                  provided in this Agreement, MCIm may audit BellSouth's books,
                  records and other documents once in each Contract Year for the
                  purpose of evaluating the accuracy of BellSouth's billing and
                  invoicing. MCIm may employ other persons or firms for this
                  purpose. Such audit shall take place at a time and place
                  agreed on by the Parties no later than thirty (30) days after
                  notice thereof to BellSouth.

                  22.1.2 BellSouth shall promptly correct any billing error that
                  is revealed in an audit, including making refund of any
                  overpayment by MCIm in the form of a credit on the invoice for
                  the first full billing cycle after the Parties have agreed
                  upon the accuracy of the audit results. Any Disputes
                  concerning audit results shall be resolved pursuant to the
                  Dispute Resolution Procedures described in Section 23 of this
                  Attachment.

                  22.1.3 BellSouth shall cooperate fully in any such audit,
                  providing reasonable access to any and all appropriate
                  BellSouth employees

                                                                     Part A - 18
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  and books, records and other documents reasonably necessary to
                  assess the accuracy of BellSouth's bills.

                  22.1.4 MCIm may audit BellSouth's books, records and documents
                  more than once during any Contract Year if the previous audit
                  found previously uncorrected net variances or errors in
                  invoices in BellSouth's favor with an aggregate value of at
                  least two percent (2%) of the amounts payable by MCIm for
                  Services and Elements or Combinations provided during the
                  period covered by the audit.

                  22.1.5 Audits shall be at MCIm's expense, subject to
                  reimbursement by BellSouth in the event that an audit finds an
                  adjustment in the charges or in any invoice paid or payable by
                  MCIm hereunder by an amount that is, on an annualized basis,
                  greater than two percent (2%) of the aggregate charges for the
                  Services and Elements during the period covered by the audit.

                  22.1.6 Upon (i) the discovery by BellSouth of overcharges not
                  previously reimbursed to MCIm or (ii) the resolution of
                  disputed audits, BellSouth shall promptly reimburse MCIm the
                  amount of any overpayment times the highest interest rate (in
                  decimal value) which may be levied by law for commercial
                  transactions, compounded daily for the number of days from the
                  date of overpayment to and including the date that payment is
                  actually made. In no event, however, shall interest be
                  assessed on any previously assessed or accrued late payment
                  charges.

         22.2 Subject to reasonable security requirements, either Party may
         audit the books, records and other documents of the other for the
         purpose of evaluating usage pertaining to transport and termination of
         local traffic. Where such usage data is being transmitted through CABS,
         the audit shall be conducted in accordance with CABS or other
         applicable requirements approved by the appropriate State Commission.
         If data is not being transferred via CABS, either Party may request an
         audit for such purpose once each Contract Year. Either Party may employ
         other persons or firms for this purpose. Any such audit shall take
         place no later than thirty (30) days after notice thereof to the other
         Party.

                  22.2.1 Either Party shall promptly correct any reported usage
                  error that is revealed in an audit, including making payment
                  of any underpayment after the Parties have agreed upon the
                  accuracy of the audit results. Any Disputes concerning audit
                  results shall be resolved pursuant to the Dispute Resolution
                  Procedures described in Section 23 of Part A of this
                  Agreement.

                                                                     Part A - 19
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  22.2.2 The Parties shall cooperate fully in any such audit,
                  providing reasonable access to any and all appropriate
                  employees and books, records and other documents reasonably
                  necessary to assess the usage pertaining to transport and
                  terminating of local traffic.

         22.3 This Section 22 shall survive expiration or termination of this
         Agreement shall for a period of two (2) years after expiration or
         termination of this Agreement.

SECTION 23. DISPUTE RESOLUTION PROCEDURES

The parties recognize and agree that the Commission has continuing jurisdiction
to implement and enforce all terms and conditions of this Agreement.
Accordingly, the parties agree that any dispute arising out of or relating to
this Agreement that the parties themselves cannot resolve, may be submitted to
the Commission for resolution. The parties agree to seek expedited resolution by
the Commission, and shall request that resolution occur in no event later than
sixty (60) days from the date of submission of such dispute. If the Commission
appoints an expert(s) or other facilitator(s) to assist in its decision making,
each party shall pay half of the fees and expenses so incurred. During the
Commission proceeding each party shall continue to perform its obligations under
this Agreement; provided, however that neither party shall be required to act in
any unlawful fashion. This provision shall not preclude the parties from seeking
relief available in any other forum.

SECTION 24. BONA FIDE REQUEST PROCESS FOR FURTHER UNBUNDLING

BellSouth shall, upon request of MCIm, and to the extent technically feasible,
provide to MCIm access to its unbundled elements for the provision of MCIm's
telecommunications service. Any request by MCIm for access to an unbundled
element that is not already available shall be treated as an unbundled element
Bona Fide Request. The parties shall adhere to the process as agreed and
described in Exhibit 1.

SECTION 25. BRANDING

         25.1 In all cases in which BellSouth has control over handling of
         services MCIm may provide using services provided by BellSouth under
         this Agreement, BellSouth shall brand any and all such services at all
         points of customer contact exclusively as MCIm services, or otherwise
         as MCIm may specify, or be provided with no brand at all, as MCIm shall
         determine. BellSouth may not unreasonably interfere with branding by
         MCIm. If for any reason, BellSouth finds that it is not possible to
         brand operator

                                                                     Part A - 20
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         services and directory service calls for MCIm, BellSouth shall revert
         to generic unbranding for all local service providers, including
         itself.

         25.2 MCIm shall provide the exclusive interface to MCIm subscribers,
         except as MCIm shall otherwise specify. In those instances where MCIm
         requires BellSouth personnel or systems to interface with MCIm
         subscribers, such BellSouth personnel shall identify themselves as
         representing MCIm, or such brand as MCIm may specify, and shall not
         identify themselves as representing BellSouth or any other entity, and
         shall refrain from marketing BellSouth, directly or indirectly, to MCIm
         subscribers.

         25.3 BellSouth shall distribute to MCIm subscribers materials provided
         by MCIm. Such materials shall be prepared by MCIm and provided in
         sufficient quantities to BellSouth at MCIm's cost. All forms, business
         cards or other business materials furnished by BellSouth to MCIm
         subscribers shall be provided by MCIm unless otherwise agreed by MCIm,
         in its sole discretion, in which case, any such customer materials
         shall be subject to MCIm's prior review and approval, and shall bear no
         corporate name, logo, trademark or trade names other than MCIm or its
         Affiliates or such other brand as MCIm, in its sole discretion, shall
         determine. If, however, the technician does not have a company specific
         card available at the time services are performed, the BellSouth
         technician shall use a generic card.

         25.4 Except as specifically permitted MCIm, in no event shall BellSouth
         provide information to MCIm subscribers about MCIm or MCIm's products
         or services.

         25.5 BellSouth shall provide, for MCIm's review and approval, the
         methods and procedures, training and approaches to be used by BellSouth
         to assure that BellSouth meets MCIm's branding requirements.

         25.6 This Section 25 shall not confer on either party rights to the
         service marks, trademarks and trade names owned by or used in
         connection with services by the other party or its Affiliates, except
         as expressly permitted by the other party.

         25.7 BellSouth will not be liable for any error, mistake or omission,
         other than intentional acts or omissions or gross negligence, resulting
         from the requirements to distribute MCIm's leave behind materials.

SECTION 26. TAXES

         26.1 Definition

                                                                     Part A - 21
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         For purposes of this Section 26, the terms "taxes" and "fees" shall
         include but not be limited to federal, state or local sales, use,
         excise, gross receipts or other taxes or tax-like fees of whatever
         nature and however designated (including tariff surcharges and any
         fees, charges or other payments, contractual or otherwise, for the use
         of public streets or rights of way, whether designated as franchise
         fees or otherwise) imposed, or sought to be imposed, on either of the
         parties and measured by the charges or payments, for the services
         furnished hereunder, excluding any taxes levied on income.

         26.2 Taxes And Fees Imposed Directly On Either Seller Or Purchaser

                  26.2.1 Taxes and fees imposed on the providing Party, which
                  are neither permitted nor required to be passed on by the
                  providing Party to its Customer, shall be borne and paid by
                  the providing Party.

                  26.2.2 Taxes and fees imposed on the purchasing Party, which
                  are not required to be collected and/or remitted by the
                  providing Party, shall be borne and paid by the purchasing
                  Party.

         26.3 Taxes And Fees Imposed On Purchaser But Collected And
         Remitted By Seller

                  26.3.1 Taxes and fees imposed on the purchasing Party shall be
                  borne by the purchasing Party, even if the obligation to
                  collect and/or remit such taxes or fees is placed on the
                  providing Party.

                  26.3.2 To the extent permitted by Applicable Law, any such
                  taxes and/or fees shall be shown as separate items on
                  applicable billing documents between the Parties.
                  Notwithstanding the foregoing, the purchasing Party shall
                  remain liable for any such taxes and fees regardless of
                  whether they are actually billed by the providing Party at the
                  time that the respective service is billed.

                  26.3.3 If the purchasing Party determines that in its opinion
                  any such taxes or fees are not lawfully due, the providing
                  Party shall not bill such taxes or fees to the purchasing
                  Party if the purchasing Party provides written certification,
                  reasonably satisfactory to the providing Party, stating that
                  it is exempt or otherwise not subject to the tax or fee,
                  setting forth the basis therefor, and satisfying any other
                  requirements under applicable law. If any authority seeks to
                  collect any such tax or fee that the purchasing Party has
                  determined and certified not to be lawfully due, or any such
                  tax or

                                                                     Part A - 22
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  fee that was not billed by the providing Party, the purchasing
                  Party may contest the same in good faith, at its own expense.
                  In the event that such contest must be pursued in the name of
                  the providing Party, the providing Party shall permit the
                  purchasing Party to pursue the contest in the name of
                  providing Party. In the event of any such contest, the
                  purchasing Party shall furnish the providing Party with notice
                  of the pending proceeding, the final resolution thereof and
                  any action therein that would affect the providing party's
                  obligation to collect and remit.

                  26.3.4 In the event that all or any portion of an amount
                  sought to be collected must be paid in order to contest the
                  imposition of any such tax or fee, or to avoid the existence
                  of a lien on the assets of the providing Party during the
                  pendency or such contest, the purchasing Party shall be
                  responsible for such payment and shall be entitled to the
                  benefit of any refund or recovery.

                  26.3.5 Left blank intentionally.

                  26.3.6 Notwithstanding any provision to the contrary, the
                  purchasing Party shall protect, indemnify and hold harmless
                  (and defend at the purchasing Party's expense) the providing
                  Party from and against any such tax or fee, interest or
                  penalties thereof, or other charges or payable expenses
                  (including reasonable attorney fees) with respect thereto,
                  which are reasonably and necessarily incurred by the providing
                  Party in connection with any claim for or contest of any such
                  tax or fee.

                  26.3.7 Each Party shall provide the other Party with timely
                  written notice of any assessment, proposed assessment or other
                  claim for any additional amount of such a tax or fee by a
                  taxing authority.

           26.4 Taxes And Fees Imposed On Providing Party

                  26.4.1 Taxes and fees imposed on the providing Party, which
                  are permitted or required to be passed on by the providing
                  Party to its Customer, shall be borne by the purchasing Party.

                  26.4.2 To the extent permitted by applicable law, any such
                  taxes and/or fees shall be shown as separate items on
                  applicable billing documents between the Parties.
                  Notwithstanding the foregoing, the purchasing Party shall
                  remain liable for any such taxes and fees regardless of
                  whether they are actually billed by the providing Party at the
                  time that the respective service is billed.

                                                                     Part A - 23
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  26.4.3 If the purchasing Party disagrees with the providing
                  Party's determination as to the application or basis for any
                  such tax or fees, the parties shall consult with respect to
                  the imposition and billing of such tax or fee and with respect
                  to whether to contest the imposition of such tax or fee.
                  Notwithstanding the foregoing, the providing Party shall
                  retain responsibility for determining whether and to what
                  extent any such taxes or fees are applicable. The providing
                  Party shall further retain responsibility for determining
                  whether and how to contest the imposition of such taxes or
                  fees, provided, however, the Parties agree to consult in good
                  faith as to such contest and that any such contest undertaken
                  at the request of the purchasing Party shall be at the
                  purchasing Party's expense. In the event that such contest
                  must be pursued in the name of the providing Party, providing
                  Party shall permit purchasing Party to pursue the contest in
                  the name of the providing Party and the providing Party shall
                  have the opportunity to participate fully in the preparation
                  of such contest.

                  26.4.4 If, after consultation in accordance with the preceding
                  Section 26.4.3, the purchasing Party does not agree with the
                  providing Party's final determination as to the application or
                  basis of a particular tax or fee, and if the providing Party,
                  after receipt of a written request by the purchasing Party to
                  contest the imposition of such tax or fee with the imposing
                  authority, fails or refuses to pursue such contest or to allow
                  such contest by the purchasing Party, the purchasing Party may
                  utilize the dispute resolution process outlined in Section 16
                  of the General Terms and Conditions of this Agreement and
                  Attachment 1. Utilization of the dispute resolution process
                  shall not relieve the purchasing party from liability for any
                  tax or fee billed by the providing Party pursuant to this
                  subsection during the pendency of such dispute resolution
                  proceeding. In the event that the purchasing Party prevails in
                  such dispute resolution proceeding, it shall be entitled to a
                  refund in accordance with the final decision therein.
                  Notwithstanding the foregoing, if at any time prior to a final
                  decision in such dispute resolution proceeding the providing
                  Party initiates a contest with the imposing authority with
                  respect to any of the issues involved in such dispute
                  resolution proceeding, the dispute resolution proceeding shall
                  be dismissed as to such common issues and the final decision
                  rendered in the contest with the imposing authority shall
                  control as to such issues.

                  26.4.5 In the event that all or any portion of an amount
                  sought to be collected must be paid in order to contest the
                  imposition of any such tax or fee with the imposing authority,
                  or to avoid the

                                                                     Part A - 24
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  existence of a lien on the assets of the providing Party
                  during the pendency of such contest, the purchasing Party
                  shall be responsible for such payment and shall be entitled to
                  the benefit of any refund or recovery.

                  26.4.6 Left blank intentionally.

                  26.4.7 Notwithstanding any provision to the contrary, the
                  purchasing Party shall protect, indemnify and hold harmless
                  (and defend at the purchasing Party's expense) the providing
                  Party from and against any such tax or fee, interest or
                  penalties thereon, or other reasonable charges or payable
                  expenses (including reasonable attorney fees) with respect
                  thereto, which are incurred by the providing Party in
                  connection with any claim for or contest of any such tax or
                  fee.

                  26.4.8 Each Party shall provide the other Party with timely
                  written notice of any assessment, proposed assessment or other
                  claim for any additional amount of such a tax or fee by a
                  taxing authority.

         26.5 Mutual Cooperation

         Unless otherwise provided herein, in any contest of a tax or fee by one
         Party, the other Party shall cooperate fully by providing records,
         testimony and such additional information or assistance as may
         reasonably be necessary to pursue the contest. Further, the other Party
         shall be reimbursed for any reasonable and necessary out-of-pocket
         copying and travel expenses incurred in assisting in such contest.

SECTION 27. RESPONSIBILITY FOR ENVIRONMENTAL CONTAMINATION

         27.1 MCIm shall in no event be liable to BellSouth for any costs
         whatsoever resulting from the presence or release of any environmental
         hazard that MCIm did not introduce to the affected work location so
         long as MCIm's actions do not cause or substantially contribute to the
         release of any Environmental Hazard. BellSouth shall, at MCIm's
         request, indemnify, defend, and hold harmless MCIm, each of its
         officers, directors and employees from and against any losses, damages,
         claims, demands, suits, liabilities, fines, penalties and expenses
         (including reasonable attorneys fees) that arise out of or from (i) any
         environmental hazard that BellSouth, its contractors or agents
         introduce to the work locations or (ii) the presence or release of any
         environmental hazard for which BellSouth is responsible under
         Applicable Law, to the extent the release of any Environmental Hazard
         is not caused or substantially contributed to by MCIm's actions.

                                                                     Part A - 25
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         27.2 BellSouth shall in no event be liable to MCIm for any costs
         whatsoever resulting from the presence or release of any environmental
         hazard that BellSouth did not introduce to the affected work location,
         so long as BellSouth's actions do not cause or substantially
         contribute to the release of any Environmental Hazards. MCIm shall, at
         BellSouth's request, indemnify, defend, and hold harmless BellSouth,
         each of its officers, directors and employees from and against any
         losses, damages, claims, demands, suits, liabilities, fines, penalties
         and expenses (including reasonable attorneys' fees) that arise out of
         or result from (i) any environmental hazard that MCIm, its contractors
         or agents introduce to the work locations, or (ii) the presence of
         release of any environmental hazard for which MCIm is responsible under
         applicable law to the extent the release of any Environmental Hazard is
         not caused or substantially contributed to by BellSouth's actions.

SECTION 28. AMENDMENTS AND MODIFICATIONS

No provision of this Agreement shall be deemed waived, amended or modified by
either party unless such a waiver, amendment or modification is in writing,
dated, and signed by both parties.

SECTION 29. SEVERABILITY

Subject to Section 2 - Regulatory Approvals, if any part of this Agreement is
held to be invalid for any reason, such invalidity will affect only the portion
of this Agreement which is invalid. In all other respects this Agreement will
stand as if such invalid provision had not been a part thereof, and the
remainder of the Agreement shall remain in full force and effect.

SECTION 30. HEADINGS NOT CONTROLLING

The headings and numbering of Sections, Parts and Attachments in this Agreement
are for convenience only and shall not be construed to define or limit any of
the terms herein or affect the meaning or interpretation of this Agreement.

SECTION 31. ENTIRE AGREEMENT

This Agreement, including all Parts and Attachments and subordinate documents
attached hereto or referenced herein, all of which are hereby incorporated by
reference herein, constitute the entire matter thereof, and supersede all prior
oral or written agreements, representations, statements, negotiations,
understandings, proposals, and undertakings with respect to the subject matter
thereof.

                                                                     Part A - 26
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement


SECTION 32. COUNTERPARTS

This Agreement may be executed in counterparts. Each counterpart shall be
considered an original and such counterparts shall together constitute one and
the same instrument.

SECTION 33. SUCCESSORS AND ASSIGNS

This Agreement shall be binding upon, and inure to the benefit of, the parties
hereto and their respective successors and permitted assigns.

SECTION 34

The Parties acknowledge that they have incorporated into this Agreement the
provisions listed in Exhibit 2 which were adopted from the arbitrated provisions
contained in the draft agreement between AT&T and BellSouth as reflected in
Order Approving Arbitrated Interconnection Agreement, Docket No. 96-AD-0559, In
the Matter of the Interconnection Agreement Negotiations Between AT&T
Communications of the South Central States, Inc., and BellSouth
Telecommunications, Inc., Pursuant to 47 U.S.C. ss. 252, dated May 8, 1997
("AT&T/BellSouth Agreement"). The Parties agree that if any further order of the
Commission, the Federal Communications Commission or a court of competent
jurisdiction requires or contemplates alteration and/or modification of any of
these arbitrated provisions in the AT&T/BellSouth Agreement, such alterations
and/or modifications shall apply to the corresponding provisions incorporated in
this Agreement effective immediately upon issuance of the court or agency order
requiring alteration and/or modification. In the event of any final order not
stayed requiring or contemplating alteration and/or modification of the
provisions listed in Exhibit 2, the Parties further agree that they will execute
a signed writing amending this Agreement to reflect such alterations and/or
modifications within 30 days of the issuance of any court or agency order
altering and/or modifying the AT&T/BellSouth Agreement, unless a request for
stay of such order is pending or a stay has been granted, regardless of any
intention by either of them to further appeal such order. The Parties further
agree that this paragraph shall not apply to provisions of the AT&T/BellSouth
Agreement, whether arbitrated or negotiated, that have not been listed in any of
the provisions listed in Exhibit 2

SECTION 35  EFFECTIVE DATE

This Agreement shall be deemed Effective when signed by the Parties and approved
by the Mississippi Public Service Commission.

                                                                     Part A - 27
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

IN WITNESS WHEREOF, each of the parties has caused this Agreement to be executed
by its duly authorized representatives.

MCImetro Access Transmission                   BellSouth Telecommunications,
Service, Inc.                                  Inc.


By:                                            By:
      ---------------------------                    ---------------------------

Name:                                          Name:
      ---------------------------                    ---------------------------

Title:                                         Title:
      ---------------------------                    ---------------------------

Date:                                          Date:
      ---------------------------                    ---------------------------

                                                                     Page A - 28
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                                    EXHIBIT 1

                            BONA FIDE REQUEST PROCESS


1.0 Bona Fide Requests are to be used when MCIm requests a change to any
Services and Elements provided hereunder, including features, capabilities, or
functionality.

1.1 A Bona Fide Request shall be submitted in writing by MCIm and shall
specifically identify the required service date, technical requirements, space
requirements and/or such specifications that clearly define the request such
that BellSouth has sufficient information to analyze and prepare a response.
Such a request also shall include, MCIm's designation of the request as being
(i) pursuant to the Telecommunications Act of 1996 or (ii) pursuant to the needs
of the business.

1.2 Although not expected to do so, MCIm may cancel, without penalty, a Bona
Fide Request in writing at any time. BellSouth will then cease analysis of the
request.

1.3 Within two (2) business days of its receipt, BellSouth shall acknowledge in
writing, the receipt of the Bona Fide Request and identify a single point of
contact and any additional information needed to process the request.

1.4 Except under extraordinary circumstances, within thirty (30) days of its
receipt of a Bona Fide Request, BellSouth shall provide to MCIm a preliminary
analysis of the Bona Fide Request. The preliminary analysis will include
BellSouth's proposed price (plus or minus 25 percent) and state whether
BellSouth can meet MCIm's requirements, the requested availability date, or, if
BellSouth cannot meet such date, provide an alternative proposed date together
with a detailed explanation as to why BellSouth is not able to meet MCIm's
requested availability date. BellSouth also shall indicate in this analysis its
agreement or disagreement with MCIm's designation of the request as being
pursuant to the Act or pursuant to the needs of the business. If BellSouth does
not agree with MCIm's designation, it may utilize the Dispute Resolution Process
provided in this Agreement. In no event, however, shall any such dispute delay
BellSouth's processing of the request. If BellSouth determines that it is not
able to provide MCIm with a preliminary analysis with thirty (30) days of
BellSouth's receipt of a Bone Fide Need request, BellSouth will inform MCIm as
soon as practicable. MCIm and BellSouth will then determine a mutually agreeable
date for receipt of the preliminary analysis.

1.5 As soon as possible, but in no event more than ninety (90) days after
receipt of the request, BellSouth shall provide MCIm with a firm Bona Fide
Request

March 25, 1997                                                       Part A - 29
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

quote which will include at a minimum, the firm availability date, the
applicable rates and the installation intervals, and a binding price quote.

1.6 Unless MCIm agrees otherwise, all proposed prices shall be the pricing
principles of this Agreement, in accordance with the Act, and any applicable FCC
and Commission rules and regulations. Payments for services purchased under a
Bona Fide Request will be made as specified in this Agreement, unless otherwise
agreed to by MCIm.

1.7 Within thirty (30) days after receiving the firm Bona Fide Request quote
from BellSouth, MCIm will notify BellSouth in writing of its acceptance or
rejection of BellSouth's proposal. If at any time an agreement cannot be reached
as to the terms and conditions or price of the request, or if BellSouth responds
that it cannot or will not offer the requested item in the Bona Fide Request and
MCIm deems the item essential to its business operations, and deems BellSouth's
position to be inconsistent with the Act, FCC or Commission regulations and/or
the requirements of this Agreement, the Dispute Resolution Process set forth in
this Agreement may be used by either Party to reach a resolution.


March 25, 1997                                                       Part A - 30
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                                                                    Page 1 of 2
                                    EXHIBIT 2

--------------------------------------------------------------------------------
PART / ATTACHMENT                                  SECTION
--------------------------------------------------------------------------------
A - General Terms & Conditions                     1.2.1 - 1.2.2
--------------------------------------------------------------------------------
A                                                  11-12
--------------------------------------------------------------------------------
A                                                  15.2
--------------------------------------------------------------------------------
A                                                  19
--------------------------------------------------------------------------------
A                                                  20.2
--------------------------------------------------------------------------------
A                                                  22
--------------------------------------------------------------------------------
A                                                  25.1
--------------------------------------------------------------------------------
A                                                  25.7
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
I - Pricing                                        2.1 (Wholesale Discount)
--------------------------------------------------------------------------------
I                                                  Table 1 (Pricing Table)
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
II - Resale                                        2.2
--------------------------------------------------------------------------------
II                                                 2.2.2 (all subsections)
--------------------------------------------------------------------------------
II                                                 2.3.3
--------------------------------------------------------------------------------
II                                                 2.3.4
--------------------------------------------------------------------------------
II                                                 2.3.5 (all subsections)
--------------------------------------------------------------------------------
II                                                 2.3.6 (all subsections)
--------------------------------------------------------------------------------
II                                                 2.3.7
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
III - Network Elements                             2.3
--------------------------------------------------------------------------------
III                                                2.4
--------------------------------------------------------------------------------
III                                                2.7
--------------------------------------------------------------------------------
III                                                4.4.1.1.1
--------------------------------------------------------------------------------
III                                                4.5.4
--------------------------------------------------------------------------------
III                                                4.6.1.1
--------------------------------------------------------------------------------
III                                                7.1.2
--------------------------------------------------------------------------------
III                                                7.2.1.2
--------------------------------------------------------------------------------
III                                                7.2.1.3
--------------------------------------------------------------------------------
III                                                7.2.1.16
--------------------------------------------------------------------------------
III                                                7.2.1.17
--------------------------------------------------------------------------------

                                                                    Page 2 of 2
III                                                7.2.2.2.2
--------------------------------------------------------------------------------
III                                                7.2.2.2.3
--------------------------------------------------------------------------------
III                                                10.1.4.2
--------------------------------------------------------------------------------
III                                                13.4.2.25 (all subsections)
--------------------------------------------------------------------------------
III                                                14.1
--------------------------------------------------------------------------------
III                                                14.2.1.2
--------------------------------------------------------------------------------
III                                                14.2.1.5
--------------------------------------------------------------------------------
III                                                14.2.9.
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

March 25, 1997                                                       Part A - 31
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

--------------------------------------------------------------------------------
PART / ATTACHMENT                              SECTION
--------------------------------------------------------------------------------
IV - Interconnection                           2.2.2.1 - 2.2.2.2
--------------------------------------------------------------------------------
IV                                             2.4.1 - 2.4.3
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
VI - Rights of Way                             1.1.28
--------------------------------------------------------------------------------
VI                                             1.2.6
--------------------------------------------------------------------------------
VI                                             1.2.9.5
--------------------------------------------------------------------------------
VI                                             1.3.6.7
--------------------------------------------------------------------------------
VI                                             1.3.9.3
--------------------------------------------------------------------------------
VI                                             1.3.9.4
--------------------------------------------------------------------------------
VI                                             1.5.2.2
--------------------------------------------------------------------------------
VI                                             1.6.3
--------------------------------------------------------------------------------
VI                                             2 (all subsections)
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
VIII - Business Processes                      2.1.5.3
--------------------------------------------------------------------------------
VIII                                           2.1.5.4
--------------------------------------------------------------------------------
VIII                                           2.2.15.1, 2.2.15.4 - 2.2.15.6
--------------------------------------------------------------------------------
VIII                                           2.3.2.3.1.2
--------------------------------------------------------------------------------
VIII                                           2.3.2.6
--------------------------------------------------------------------------------
VIII                                           2.5 (all subsections)
--------------------------------------------------------------------------------
VIII                                           3.4 (all subsections)
--------------------------------------------------------------------------------
VIII                                           4.1.1.7
--------------------------------------------------------------------------------
VIII                                           4.4 (all subsections)
--------------------------------------------------------------------------------
VIII                                           4.5 (all subsections)
--------------------------------------------------------------------------------
VIII                                           5.1.14
--------------------------------------------------------------------------------
VIII                                           5.4 (all subsections)
--------------------------------------------------------------------------------
VIII                                           6.1.2.1
--------------------------------------------------------------------------------
VIII                                           6.1.2.2
--------------------------------------------------------------------------------
VIII                                           6.1.2.3
--------------------------------------------------------------------------------
VIII                                           6.1.2.3.8
--------------------------------------------------------------------------------
VIII                                           6.1.2.3.9.3
--------------------------------------------------------------------------------
VIII                                           6.1.3.1
--------------------------------------------------------------------------------
VIII                                           6.1.3.2
--------------------------------------------------------------------------------
VIII                                           6.1.3.3
--------------------------------------------------------------------------------
VIII                                           6.1.3.3.2
--------------------------------------------------------------------------------
VIII                                           6.1.3.15
--------------------------------------------------------------------------------
VIII                                           6.1.4.1.1
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
IX - Network Security                          3.1
--------------------------------------------------------------------------------
IX                                             3.1.2 - 3.1.3
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
X - Credits for Performance                    Entire Attachment
Standard Failures
--------------------------------------------------------------------------------

March 25, 1997                                                       Part A - 32
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement








March 25, 1997                                                       Part A - 33
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                             PART B -- DEFINITIONS

"911 SITE ADMINISTRATOR" is a person assigned by MCIm to establish and maintain
E911 service location information for its subscribers.

"911 SERVICE" means a universal telephone number which gives the public direct
access to the Public Safety Answering Point (PSAP). Basic 911 service collects
911 calls from one or more local exchange switches that serve a geographic area.
The calls are then sent to the correct authority designated to receive such
calls.

"ASR" (ACCESS SERVICE REQUEST) means the industry standard forms and supporting
documentation used for ordering Access Services. The ASR may be used to order
trunking and facilities between MCIm and ILEC for Local Interconnection.

"ACCESS SERVICES" refers to interstate and intrastate switched access and
private line transport services.

"ACT" means the Communications Act of 1934 as amended.

"AIN" (ADVANCED INTELLIGENT NETWORK) is a network functionality that permits
specific conditions to be programmed into a switch which, when met, directs the
switch to suspend call processing and to receive special instructions for
further call handling instructions in order to enable carriers to offer advanced
features and services.

"AFFILIATE" is a person that (directly or indirectly) owns or controls, is owned
or controlled by, or is under common ownership or control with, another person.
For the purposes of this paragraph, the term "own" means to own an equity
interest (or the equivalent thereof) of more than 10 percent.

"ALI" (AUTOMATIC LOCATION IDENTIFICATION) is a proprietary database developed
for E911 systems that provides for a visual display of the caller's telephone
number, address and the names of the emergency response agencies that are
responsible for that address. The Alternative Local Exchange Company will
provide ALI record information in National Emergency Number Association (NENA)
Version #2 format. The ALI also shows an Interim Number Portability (INP) number
if applicable.

                                                                       Part B-1
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

"ALI/DMS" (AUTOMATIC LOCATION IDENTIFICATION/DATA MANAGEMENT SYSTEM) means the
emergency service (E911/911) database containing customer location information
(including name, address, telephone number, and sometimes special information
from the local service provider) used to determine to which Public Safety
Answering Point (PSAP) to route the call.

"AMA" means the Automated Message Accounting structure inherent in switch
technology that initially records telecommunication message information. AMA
format is contained in the Automated Message Accounting document, published by
Bellcore as GR-1100-CORE which defines the industry standard for message
recording.

"ANI"  (AUTOMATIC  NUMBER  IDENTIFICATION)  is a  feature  that  identifies  and
displays the number of a telephone that originates a call.

"ARS" (AUTOMATIC ROUTE SELECTION) is a service feature that provides for
automatic selection of the least expensive or most appropriate transmission
facility for each call based on criteria programmed into the system.

"BLVBLI" (Busy LINE VERIFY/BUSY LINE INTERRUPT) means an operator call in which
the end user inquiries as to the busy status of, or requests an interruption of,
a call on an Exchange Service.

"BST" and "BellSouth" both mean BellSouth Telecommunications, Inc.

"CABS" means the Carrier Access Billing System which is defined in a document
prepared under the direction of the Billing Committee of the OBF. The Carrier
Access Billing System document is published by Bellcore in Volumes 1, 1A, 2, 3,
3A, 4 and 5 as Special Reports SR-OPT-001868, SR-OPT-0011869, SR-OPT- 001871,
SR-OPT-001872, SR-OPT-001873, SR-OPT-001874, and SR-OPT-001875, respectively,
and contains the recommended guidelines for the billing of access and other
connectivity services.

"CCS" (COMMON CHANNEL SIGNALING) means a method of digitally transmitting call
set-up and network control data over a digital signaling network fully separate
from the public switched telephone network that carriers the actual call.

                                                                      Part B-2
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

"CLEC" means a Competitive Local Exchange Carrier.

"CPN" (CALLING PARTY NUMBER) is a Common Channel Signaling parameter which
refers to the number transmitted through the network identifying the calling
party.

"CENTRAL OFFICE SWITCH" or "CENTRAL OFFICE" means a switching entity within the
public switched network, including but not limited to end office switches and
tandem office switches. Central office switches may be employed as combination
End Office/Tandem Office Switches (Combination Class 5/Class 4).

"CENTREX" means a Telecommunications Service that uses central office switching
equipment for call routing to handle direct dialing of calls, and to provide
numerous private branch exchange-like features.

"CHARGE NUMBER" is a CCS parameter which refers to the number transmitted
through the network identifying the billing number of the calling party.

"CLASS" (Bellcore Service Mark) -- Set of call-management service features that
utilize the capability to forward a calling party's number between end offices
as part of call setup. Features include Automatic Callback, Automatic Recall,
Caller ID, Call Trace, and Distinctive Ringing.

"COLLOCATION" means the right of MCIm to place equipment of its choice in
BellSouth's central offices or other BellSouth locations as described in the
rules and regulations of the FCC in effect.

"COMBINATIONS" means provision by ILEC of two or more connected Network Elements
ordered by MCIm to provide its telecommunication services in a geographic area
or to a specific customer and that are placed on the same order by MCIm.

"COMMISSION" means the Mississippi Public Service Commission.

"CONDUIT" means a tube or protected pathway that may be used to house
communication or electrical cables. Conduit may be underground or above ground
(for example, inside buildings) and may contain one or more inner ducts.

"CONFIDENTIAL INFORMATION" has that meaning set forth in

                                                                       Part B-3
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

Section 21 of Part A -- General Terms.

"CONTRACT YEAR" means a twelve (12) month period during the term of the contract
commencing on the Effective Date and each anniversary thereof.

"CONTROL OFFICE" is an exchange carrier center or office designated as its
company's single point of contact for the provisioning and maintenance of its
portion of local interconnection arrangements.

"CUSTOM CALLING FEATURES" -- Set of call-management service features available
to residential and single-line business customers including call-waiting,
call-forwarding and three-party calling.

"DBMS" (DATABASE MANAGEMENT SYSTEM) is a computer system used to store, sort,
manipulate and update the data required to provide selective routing and ALI.

"DIRECTORY ASSISTANCE DATABASE" refers to any subscriber recorder used by the
ILEC in its provision of live or automated operator-assisted directory
assistance including but not limited to 411, 555-1212, NPA-555-1212.

"DIRECTORY ASSISTANCE SERVICES" provides Listings to callers. Directory
Assistance Services may include the option to complete the call at the caller's
direction.

"DIRECTORY LISTINGS" refers to subscriber information, including but not limited
to name, address and phone numbers, that is published in any media, including
but not limited to traditional white/yellow page directories, specialty
directories, CD ROM, and other electronic formats.

"DISCLOSER" means that party to this Agreement which has disclosed Confidential
Information to the other party.

"E911" (ENHANCED 911 SERVICE) means a telephone communication service which will
automatically route a call dialed "911" to a designated public safety answering
point (PSAP) attendant and will provide to the attendant the calling party's
telephone number and, when possible, the address from which the call is being
placed and the emergency response agencies responsible for the location from
which the call was dialed.

                                                                       Part B-4
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

"E911 Message Trunk" is a dedicated line, trunk or channel between two central
offices or switching devices which provides a voice and signaling path for E911
calls.

"EIS" (EXPANDED INTERCONNECTION SERVICE) is the collocation arrangement which
ILEC provides in its designated wire centers.

"EMR" means the Exchange Message Record System used among ILECs for exchanging
telecommunications message information for billable, non-billable, sample,
settlement and study data. EMR format is contained in BR-010-200-010 CRIS
Exchange Message Record, published by Bellcore and which defines the industry
standard for exchange message records.

"ESN" (EMERGENCY SERVICE NUMBER) is a number assigned to the ALI and selective
routing databases for all subscriber telephone numbers. The ESN designates a
unique combination of fire, police and emergency medical service response
agencies that serve the address location of each in-service telephone number.

"EFFECTIVE DATE" is the date indicated in Part A on which the Agreement shall
become effective.

"EMERGENCY RESPONSE AGENCY" is a governmental entity authorized to respond to
requests from the public to meet emergencies.

"ENHANCED DIRECTORY ASSISTANCE" refers to directory Assistance services,
including but not limited to reverse search, talking yellow pages, and locator
services.

"ENHANCED WHITE PAGES" means optional features available for White Pages
Directory listings (e.g., bold, all capitals, logos).

"ENHANCED YELLOW PAGES" means optional features available for Yellow Pages
Directory listings (e.g., red type, bold, all capital, additional line of text,
indented).

"ENVIRONMENTAL HAZARD" means (1) a release, discharge, leak, spill or disposal
(collectively referred to hereafter as "release") of HAZARDOUS MATERIALS has
occurred on premises or property that is related to the performance of this
Agreement and that such affected material or media is demonstrated through

                                                                       Part B-5
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

applicable or appropriate testing method to require remediation or removal as
determined by all laws, ordinances, statutes, codes, rules, regulations, orders
and decrees of the United States, the state, county, city or any other political
subdivision in which the release has occurred, and any other political
subdivision in which the release has occurred, and any other political
subdivision, agency, or instrumentality exercising jurisdiction over the
release, including any applicable federal and state case law and common law
interpreting any of the foregoing or (2) any event involving, or exposure to,
HAZARDOUS MATERIALS which poses risks to human health, safety or the environment
(including, without limitation, indoor or outdoor environment(s) and is
regulated under any applicable laws or regulations as described in (1).

"FCC Interconnection Order" is the Federal Communications
Commission's First Report and Order in CC Docket No. 96-98
released August 8, 1996.

"HAZARDOUS MATERIALS" means any hazardous or toxic substance, material or waste
listed in the United States Department of Transportation HAZARDOUS MATERIALS
Table at 49 CFR 172.101; and hazardous substance listed by the Environmental
Protection Agency (EPA) under the Comprehensive Environmental, Response,
Compensation, and Liability Act (CERCLA), 42 U.S.C. sec. 9601, et. seq., as
amended, and found at 40 CFR Part 302; any hazardous waste listed under the
Resource Conservation and Recovery Act (RCRA), 42 U.S.C. sec. 6901, et. seq., as
amended, and found at 40 CFR Part 261; any toxic substance regulated by the
Toxic Substances Control Act, 15 U.S.C. sec. 2601, et. seq., as amended; any
insecticide, fungicide, or rodenticide regulated by the Federal Insecticide,
Fungicide, and Rodenticide Act, 7 U.S.C. sec. 136, et. seq., as amended; and the
following specified substances or materials, that may or may not be regulated by
the above; (1) asbestos or asbestos-containing materials; (2) petroleum or
petroleum-based or derived products or by-product; (3) polychlorinated
biphenyl's (PCBs); and (4) radon."

"ILEC" means the incumbent local exchange carrier.

"INP" (INTERIM NUMBER PORTABILITY) is a service arrangement whereby subscribers
who change local service providers may retain existing telephone numbers when
remaining at their current location or changing their location within the
geographic area serviced by the initial carrier's serving central office.

                                                                       Part B-6
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

"IP"(INTERCONNECTION POINT) is a mutually agreed upon point of demarcation where
the networks of ILEC and MCIm interconnect for the exchange of traffic.

"IXC" (INTEREXCHANGE CARRIER) means a provider of interexchange
telecommunications services.

"LIDB" (LINE INFORMATION DATA BASE(S)) A Service Control Point (SCP) database
that provides for such functions as calling card validation for telephone line
number cards issued by ILECs and other entities and validation for collect and
billed-to-third services.

"MCI" means MCI Telecommunications Corporation.

"MCIm" means MCImetro Access Transmission Services, Inc.

"MCIm 911 DATABASE RECORDS" are the MCIm customer records to be provided by MCIm
to ILEC for inclusion in ILEC's E911 database.

"MECAB" refers to the Multiple Exchange Carrier Access Billing (MECAB) document
prepared by the Billing Committee of the Ordering and Billing Forum (OBF), which
functions under the auspices of the Carrier Liaison Committee (CLC) of the
Alliance for Telecommunications Industry Solutions (ATIS). The MECAB document,
published by Bellcore as Special Report SR-BDS-000983, contains the recommended
guidelines for the billing of an access service provided by two or more LECs
(including a LEG and a CLEC), or by one LEC in two or more states within a
single LATA.

"MECOD" refers to the Multiple Exchange Carriers Ordering and Design (MECOD)
Guidelines for Access Services - Industry Support Interface, a document
developed by the Ordering/Provisioning Committee under the auspices of the
Ordering and Billing Forum (OBF), which functions under the auspices of the
Carrier Liaison Committee (CLC) of the Alliance for Telecommunications Industry
Solutions (ATIS). The MECOD document, published by Bellcore as Special Report SR
STS-002643, establishes recommended guidelines for processing orders for access
service which is to be provided by two or more LECs (including a LEG and a
CLEC). It is published by Bellcore as SRBDS 00983.

"MSAG" (MASTER STREET ADDRESS GUIDE (MSAG)) is a

                                                                       Part B-7
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

database defining the geographic area of an E911 service. It includes an
alphabetical list of the street names, high-low house number ranges, community
names, end emergency service numbers provided by the counties or their agents to
ILEC.

"NANP" means the "North American Numbering Plan," the system or method of
telephone numbering employed in the United States, Canada, and certain Caribbean
countries. It denotes the three digit Numbering Plan Area code and a seven digit
telephone number made up of a three digit Central Office code plus a four digit
station number.

"NENA" (NATIONAL EMERGENCY NUMBER ASSOCIATION (NENA)) is an association with a
mission to foster the technological advancement, availability and implementation
of 911 nationwide.

"NP" (NUMBER PORTABILITY) means the ability of users of telecommunications
services to retain, at the same location, existing telecommunications numbers
without impairment of quality, reliability, or convenience when switching from
one telecommunications carrier to another.

"NPA" (NUMBERING PLAN AREA) (sometimes referred to as an area code). Is the
three digit indicator which is designated by the first three digits of each 10
digit telephone number within the NANP. Each NPA contains 800 possible NXX
Codes. There are two general categories of NPA, "Geographic NPAs" and
"Non-Geographic NPAs." A "Geographic NPA" is associated with a defined
geographic area, and all telephone numbers bearing such NPA are associated with
services provided within that Geographic area. A "Non-Geographic NPA," also
known as a "Service Access Code (SAC Code)" is typically associated with a
specialized telecommunications service which may be provided across multiple
geographic NPA areas; 500, 800, 900, 700, and 888 are examples of Non-Geographic
NPAs.

"NXX,"  "NXX CODE," OR  "CENTRAL  OFFICE  CODE," OR "CO CODE" is the three digit
switch entity  indicator which is defined by the fourth,  fifth and sixth digits
of a 10 digit telephone number within the North America Numbering Plan ("NANP").

"NETWORK ELEMENT" means a facility or equipment used in the provision of a
telecommunications service including all features, functions and capabilities
that are embedded in such facility or equipment.

                                                                       Part B-8
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

"OBF" means the Ordering and Billing Forum, which functions under the auspices
of the Carrier Liaison Committee (CLC) of the Alliance for Telecommunications
Industry Solutions (ATIS).

"OPERATOR SYSTEMS" are network elements that provide operator and automated call
handling with billing, special operator services, subscriber telephone listings
and optional call completion services.

"OPERATOR SERVICES" provides (1) operator handling for call completion (e.g.
collect calls); (2) operator or automated assistance for billing after the
customer has dialed the called number (e.g. credit card calls); and (3) special
operator services (e.g. BLV/ELI, Emergency Agency Call).

"P.01 TRANSMISSION GRADE OF SERVICE (GOS)" means a trunk facility provisioning
standard with the statistical probability of no more than one call in 100
blocked on initial attempt during the average busy hour.

"PLU" (PERCENT LOCAL USAGE) is a calculation which represents the ratio of the
local minutes to the sum of local and intraLATA toll minutes and interLATA
minutes, if any, between exchange carriers sent over Local Interconnection
Trunks. Directory assistance, BLV/BLVI, 900, 976, transiting calls from other
exchange carriers and switched access calls are not included in the calculation
of PLU. "POP" means an IXC's point of presence.

"PSAP" (PUBLIC SAFETY ANSWERING POINT (PSAP) is the public safety communications
center where 911 calls placed by the public for a specific geographic area will
be answered

"POLE ATTACHMENT" means any attachment by a cable television system or provider
of telecommunications service to a pole, duct, conduit, or right-of-way owned or
controlled by a utility.

"PROPRIETARY information" shall have the same meaning as Confidential
Information.

"ROW" (RIGHT OF WAY  (ROW)) is the right to use the land or other  property  of
another party to place poles, conduits,  cables, other structures end equipment,
or to provide passage to access such structures and equipment.

"RATE CENTER" means the geographic point and corresponding geographic area which
are associated with one or more particular

                                                                       Part B-9
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

NPA-NXX codes which have been assigned to ILEC (or MCIm) for its provision of
Basic Exchange Telecommunications Services. The "rate center point" is the
finite geographic point identified by a specific V&H coordinate, which is used
to measure distance-sensitive end user traffic to/from the particular NPA-NXX
designations associated with the specific Rate Center. The "rate center area" is
the exclusive geographic area identified as the area within which ILEC (or MCIm)
will provide Basic Exchange Telecommunications Services bearing the particular
NPA-NXX designations associated with the specific Rate Center. The Rate Center
point must be located within the Rate Center area.

"REAL TIME" means the actual time in which an event takes place, with the
reporting on or the recording of the event simultaneous with its occurrence.

"RECIPIENT"- means that party to this Agreement (a) to which Confidential
Information has been disclosed by the other party or (b) who has obtained
Confidential Information in the course of providing services under this
Agreement.

"RESELLER" is a category of Local Exchange service providers who obtain dial
tone and associated telecommunications services from another provider through
the purchase wholesale priced services for resale to their end user customers.

"ROUTING  POINT" means a location  which ILEC or MCIm has  designated on its own
network as the homing  (routing)  point for  traffic  inbound to Basic  Exchange
Services provided by the ILEC or MCIm which bear a certain NPA-NXX  designation.
The  Routing  Point  is  employed  to  calculate  mileage  measurements  for the
distance-sensitive  transport  element  charges  of  Switched  Access  Services.
Pursuant to Bellcore  Practice BR 795-100-100,  the Routing Point may be an "End
Office" location,  or a "LEC Consortium Point of  Interconnection."  Pursuant to
that same  Bellcore  Practice,  examples of the latter shall be  designated by a
common language  location  identifier (CLLI) code with (x)KD in positions 9, 10,
11, where (x) may by any alphanumeric A-Z or 0-9. The above referenced  Bellcore
document  refers  to  the  Routing  Point  as  the  Rating  Point.   The  Rating
Point/Routing  Point need not be the same as the Rate Center Point,  nor must it
be located  within  the Rate  Center  Area,  but must be in the same LATA as the
NPA-NXX..

"SECAB" means the Small Exchange Carrier Access Billing document prepared by the
Billing Committee of the OBF. The

                                                                      Part B-10
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

Small Exchange Carrier Access Billing document, published by Bellcore as Special
Report SR OPT-001856, contains the recommended guidelines for the billing of
access and other connectivity services.

"SELECTIVE ROUTING" is a service which automatically routes an E911 call to the
PSAP that has jurisdictional responsibility for the service address of the
telephone that dialed 911, irrespective of telephone company exchange or wire
center boundaries.

"SWITCH" -- See Central Office Switch

"TANDEM OFFICE SWITCHES" which are Class 4 switches which are used to connect
and switch trunk circuits between and among end office switches and other
tandems.

"TECHNICALLY FEASIBLE" Interconnection, access to Network Elements, collocation,
and other methods of achieving interconnection or access to Network Elements at
a point in the network shall be deemed technically feasible absent technical or
operational concerns that prevent the fulfillment of a request by a
telecommunications carrier for such interconnection, access, or methods. A
determination of technical feasibility does not include consideration of
economic, accounting, billing, space, or site concerns, except that space and
site concerns may be considered in circumstances where there is no possibility
of expanding the space available. The fact that an incumbent LEC must modify its
facilities or equipment to respond to such request does not determine whether
satisfying such request is technically feasible. An incumbent LEC that claims
that it cannot satisfy such request because of adverse network reliability
impacts must prove to the state Commission by clear and convincing evidence that
such interconnection, access, or methods would result in specific and
significant adverse network reliability impacts.

"TELECOMMUNICATIONS" means the transmission, between or among points specified
by the user, of information of the user's choosing, without change in the form
or content of the information as sent and received.

"TELECOMMUNICATION  SERVICES" means the offering of telecommunications for a fee
directly  to the  public,  or to such  classes  of  users  as to be  effectively
available directly to the public,  regardless of the facilities used. As used in
this definition.

"THOUSANDS BLOCK OF NUMBERS" shall mean 1000 or more

                                                                      Part B-11
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

consecutive numbers beginning and ending on a digit boundary, e.g., 949-1000 to
949-1999.

"TRCO" means Trouble Reporting Control Office.

"VOLUNTARY FEDERAL CUSTOMER FINANCIAL ASSISTANCE PROGRAMS" are
Telecommunications Services provided to low-income subscribers, pursuant to
requirements established by the appropriate state regulatory body.

"WIRE CENTER"- denotes a building or space within a building which serves as an
aggregation point on a given carrier's network, where transmission facilities
and circuits are connected or switched. Wire center can also denote a building
in which one or more central offices, used for the provision of Basic Exchange
Services and access services, are located. However, for purposes of EIC service,
Wire Center shall mean those points eligible for such connections as specified
in the FCC Docket No. 91 - 141, and rules adopted pursuant thereto.

                                                                      Part B-12
<PAGE>

                                                                        Table 2

                              PHYSICAL COLLOCATION

                     (all prices are interim at this time)
--------------------------------------------------------------------------------
Application - Per Arrangement/Per Location-Nonrecurring              $ 3,100.00

Space Preparation Fee - Nonrecurring                                        ICB
Space Construction Fee - Nonrecurring                                $ 3,750.00
Cable Installation - Per Entrance Cable                              $ 2,750.00
Floor Space Zone A, Per Square Foot, Per Month                            $4.28
Floor Space Zone B, Per Square Foot, Per Month                            $4.09
Power Per AMP, Per Month                                                  $3.86
Cable Support Structure, Per Entrance Cable                              $13.35


POT Bay (Optional Point of Termination Bay)
Per 2-Wire Cross - Connect, Per Month                                     $0.18
Per 4-Wire Cross - Connect, Per Month                                     $0.44
Per DS1 Cross - Connect, Per Month                                        $0.44
Per DS3 Cross - Connect, Per Month                                        $3.66


Cross-Connects
2-Wire Analog, Per Month                                                  $0.30
4-Wire Analog, Per Month                                                  $0.50
   Nonrecurring - First/Additional                                        $9.25
DS1, Per Month                                                            $3.07
    Nonrecurring - First/Additional                               $113.75/14.25
DS3, Per Month                                                           $39.64
    Nonrecurring - First/Additional                               $113.75/14.25


Security Escort
Basic - 1st half hour                                                    $41.00
Overtime - 1st half hour                                                 $48.00
Premium - 1st half hour                                                  $55.00


Basic - additional                                                       $25.00
Overtime - additional                                                    $30.00
Premium - additional                                                     $35.00
--------------------------------------------------------------------------------

                              VIRTUAL COLLOCATION
                     (all prices are interim at this time)

Rates tariffed by BellSouth in its FCC Tariff No. 1, Section 20.
<PAGE>

                                                                         Table 3

                                 RIGHTS OF WAY

BellSouth shall provide access to rights-of-way under standard licensing
agreements at rates that are consistent with 47 U.S.C. Section 224(d). MCIm may
file a complaint with the appropriate authority if it believes the rates
provided by BellSouth are not consistent with 47 U.S.C. Section 224(d).
<PAGE>

                                                                         Table 4

                  POLE ATTACHMENTS, CONDUIT AND DUCT OCCUPANCY

BellSouth shall provide access to poles, conduits and ducts, under standard
licensing agreements at rates that are consistent with 47 U.S.C. Section 224(d).
MCIm may file a complaint with the appropriate regulatory authority if it
believes the rates provided by BellSouth are not consistent with 47 U.S.C.
Section 224(d).
<PAGE>

                                                                         Table 5

                           INTERIM NUMBER PORTABILITY

Until a permanent rate and an appropriate cost sharing mechanism are
established, MCIm and BellSouth shall each track the number of interim number
portability arrangements they have provided. Based on the permanent rate, MCIm
and BellSouth will true-up their costs with interest. BellSouth shall provide
cost studies to assist in establishing a permanent rate within six (6) months.
<PAGE>

                                                                        Table 6

                              RECORDED USAGE DATA
                       (Interim Rates subject to True-Up)

--------------------------------------------------------------------------------
Recording Services (only applied to unbundled operator
services messages), per message                                           $.008
--------------------------------------------------------------------------------
Message Distribution, per message                                         $.004
--------------------------------------------------------------------------------
Data Transmission, per message                                            $.001
--------------------------------------------------------------------------------
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                                  ATTACHMENT I

                                 PRICE SCHEDULE

1. General Principles

     1.1 All rates provided under this Agreement are interim, subject to
     true-up, and shall remain in effect until the Commission determines
     otherwise or unless they are not in accordance with all applicable
     provisions of the Act, the Rules and Regulations of the FCC in effect, or
     the Commission's rules and regulations, in which case Part A, Section 2
     shall apply.

     1.2 Except as otherwise specified in this Agreement, the Act or any
     Commission order, each Party shall be responsible for all costs and
     expenses that it incurs to comply with its obligation under this Agreement.

2. Local Service Resale

     The rates that MCIm shall pay to BellSouth for Resale shall be an amount
     equal to BellSouth's tariffed rates for each resold service as reduced by a
     percentage amount equal to the wholesale discount (set forth below in
     section 2.1). If BellSouth reduces such tariffed rates during the term of
     this Agreement, the wholesale discount shall be applied to the reduced
     tariffed rates.

     2.1 The following wholesale discount will apply to all Telecommunications
     Services available for resale in Mississippi:

                     Residential Service: 15.75%
                     Business Service:    15.75%

3. Unbundled Network Elements

     The charges that MCIm shall pay to BellSouth for Network Elements are set
     forth in Table 1 of this Attachment.

4. Ancillary Functions and Supporting Elements

     The interim prices for collocation, AIN and other Ancillary Functions or
     Supporting Elements that MCIm shall pay to BellSouth are set forth in Table
     1 of this Attachment.

5. Recorded Usage Data

                                                               Attachment I - 1
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

     The prices for Recorded Usage data are set forth in Table 1 of this
     Attachment.

6. Inside Wire

     The price of the BellSouth Inside Wire Maintenance Plan purchased by MCIm
     for resale shall not be reduced by the wholesale discount.

7. Interconnection and Reciprocal Compensation

     7.1 Compensation for the exchange of local traffic is set forth in Table 1
     of this Attachment and shall be billed based on per-minutes-of-use and
     shall be measured in accordance with Attachment IV.

     7.2 MCIm may choose to establish trunking to any given end office when
     there is sufficient traffic to route calls directly to such end office. If
     MCIm leases one-way trunks from BellSouth, MCIm will pay the transport
     charges for dedicated or common transport. For two-way trunks the charges
     will be shared equally by both parties.

     7.3 Compensation for the termination of toll traffic and the origination of
     800/888 traffic between the interconnecting parties shall be based on the
     applicable access charges in accordance with FCC Rules and Regulations in
     effect.

     7.4 Where a toll call is completed through BellSouth Mississippi's INP
     arrangement (e.g., remote call forwarding, flexible DID, etc.) to MCIm's
     subscriber, MCIm shall be entitled to applicable access charges in
     accordance with FCC Rules and Regulations.

     7.5 MCIm shall pay a transit rate as set forth in Table 1 of this
     Attachment when MCIm uses a BellSouth access tandem to terminate a call to
     a third party LEC or another local service provider. BellSouth shall pay
     MCIm a transit rate equal to the BellSouth rate referenced above when
     BellSouth uses an MCIm switch to terminate a call to a third party LEC or
     another local service provider.

8. Interim Pricing

     The interim prices referenced above shall be subject to true-up according
     to the following procedures:

     8.1 The interim price shall be trued-up, either up or down, based on final
     prices determined either by further agreement between the Parties,

                                                                Attachment I - 2
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

     or by a final order (including any appeals) of the Commission that meets
     the criteria of 8.3 below. The Parties shall implement the true-up by
     comparing the actual volumes and demand for each item, together with
     interim prices for each item, with the final prices determined for each
     item. Each Party shall keep its own records upon which the true-up can be
     based, and any final payment from one Party to the other shall be in an
     amount agreed upon by the Parties based on such records. In the event of
     any disagreement as between the records or the Parties regarding the amount
     of such true-up, the Parties agree that either Party may submit the matter
     to the Commission pursuant to the Dispute Resolution Procedures set forth
     in Section 23 of Part A of this Agreement.

     8.2 The Parties may continue to negotiate toward final prices, but in the
     event that no such agreement is reached within nine (9) months, either
     Party may petition the Commission to resolve such disputes and to determine
     final prices for each item.

     8.3 A final order of this Commission that forms the basis of a true-up
     shall be the final order as to final prices for unbundled network elements
     in an appropriate generic cost study proceeding, or potentially may be a
     final order in any other Commission proceeding which meets the following
     criteria:

            (i) BellSouth and MCIm are entitled to be a full party to the
            proceeding;

            (ii) It shall apply the provisions of the federal Telecommunications
            Act of 1996, including but not limited to Section 252(d)(1) (which
            contains pricing standards) and all then-effective implementating
            rules and regulations; and

            (iii) It shall include as an issue the geographic deaveraging of
            unbundled element prices, which deaveraged prices, if any, are
            required by said final order, shall form the basis of any true-up.

                                                                Attachment I - 3
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement


                               TABLE OF CONTENTS

                                 ATTACHMENT II
                                  LOCAL RESALE

Section 1. Telecommunications Services Provided for Resale      II-1

Section 2. General Terms and Conditions for Resale              II-2

Section 3. Advanced Intelligent Network                         II-13

Section 4. Service Functions                                    II-14

                                                               Attachment II - i
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                                 ATTACHMENT II

                                  LOCAL RESALE

SECTION 1. TELECOMMUNICATIONS SERVICES PROVIDED FOR RESALE

         1.1 At the request of MCIm, and pursuant to the requirements of the
         Act, MPSC rulings, and FCC Rules and Regulations in effect, BellSouth
         shall make available to MCIm for resale any Telecommunications Service
         that BellSouth currently provides or may offer hereafter. BellSouth
         shall also provide Service Functions, as set forth in this Attachment
         II. The Telecommunications Services and Service Functions provided by
         BellSouth to MCIm pursuant to this Agreement are collectively referred
         to as "Local Resale."

         1.2 To the extent that this Attachment describes services which
         BellSouth shall make available to MCIm for resale pursuant to this
         Agreement, this list of services is neither all inclusive nor
         exclusive. All Telecommunications Services of BellSouth which are to be
         offered for resale are subject to the terms herein, even though they
         are not specifically enumerated or described.

         1.3 FEATURES AND FUNCTIONS SUBJECT TO RESALE. BellSouth agrees to make
         available for resale all features and functions available in connection
         with Telecommunications Services, including but not limited to the
         following:

                Dial tone and ring
                Capability for either dial pulse or touch tone recognition
                Capability to complete calls to any location
                Same extended local calling area
                1+ IntraLATA toll calling
                PIC 1+ service
                CIC dialing (10XXX) Same access to vertical features and
                functions

                                                               Attachment II - 1
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         1.4 BellSouth will provide MCIm with at least the capability to provide
         an MCIm subscriber with the same level of service quality as BellSouth
         provides its own subscribers with respect to all Telecommunications
         Services and shall provide such capability in accordance with the
         relevant requirements of Attachment VIII.

         1.5 The specific business process requirements and systems interface
         requirements are set forth in Attachment VIII.

SECTION 2. GENERAL TERMS AND CONDITIONS FOR RESALE

         2.1 PRICING. The prices charged to MCIm for Local Resale are set forth
         in Attachment I of this Agreement. The resale discount shall apply to
         non-recurring rates of services available for resale.

         2.2 SERVICES AVAILABLE FOR RESALE. MCIm may resell to any and all
         classes of end-users Telecommunications Services obtained from
         BellSouth under this Agreement, except for Lifeline Assistance and
         Link-Up or similar services, and Grandfathered services, which MCIm may
         only resell to those subscribers who are eligible to obtain such
         services from BellSouth. BellSouth will not prohibit, nor impose
         unreasonable or discriminatory conditions or limitations on the resale
         of its Telecommunications Service.

               2.2.1 BellSouth agrees to remove all tariff restrictions
               regarding resale that are inconsistent with the orders of the
               MPSC pertaining to resale.

               2.2.2 RESTRICTIONS ON RESALE With the exception of short-term
               promotions and CSA's (defined below), Lifeline, Link-up, and
               Grandfathered services, BellSouth shall offer for resale at
               wholesale prices all Telecommunications Services, including
               non-recurring services, that BellSouth provides at retail to
               non-telecommunications carriers.

               No terms and conditions, including use and user restrictions,
               shall be applicable to the resale of BellSouth's services except
               for:

                  2.2.2.1 A restriction on cross-class selling

                  2.2.2.2 Reasonable and nondiscriminatory terms, conditions and
                  limitations in the BellSouth tariffs currently applicable or
                  hereafter agreed to be applicable or made applicable by order
                  of the MSPC

                  2.2.2.3 Long term promotions, defined as those promotions

                                                               Attachment II - 2
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  that are offered for more than 90 days, shall be available for
                  resale to the subscribers who would have qualified for the
                  promotional rate if the service were being offered by
                  BellSouth;

                  2.2.2.4 Lifeline service shall be available for resale by MCIm
                  only to those subscribers who meet the qualifications set
                  forth in the applicable State and Federal Regulations.

                  2.2.2.5 Link-up service shall be available for resale by MCIm
                  only to those subscribers who meet the qualifications set
                  forth in the applicable State and Federal Regulations.

                  2.2.2.6 Grandfathered services are available for resale by
                  MCIm only to those subscribers who already have grandfathered
                  status or who may obtain such services from BellSouth.
                  Grandfathered services may not be resold to a new or different
                  group of subscribers that is not eligible to obtain such
                  services from BellSouth.

                  2.2.2.7 Left Blank Intentionally

                  2.2.2.8 Left Blank Intentionally

                  2.2.2.9 Left Blank Intentionally

                  2.2.2.10 Left Blank Intentionally

         2.3 REQUIREMENTS FOR SPECIFIC SERVICES

               2.3.1 MULTISERV(R)REQUIREMENTS

                  2.3.1.1 At MCIm's option, MCIm may purchase MULTISERV(R)
                  services. Where MCIm purchases such MULTISERV services, MCIm
                  may purchase the entire set of features, any single feature or
                  any combination of features which BellSouth has the capability
                  to provide. BellSouth will provide MCIm with the same service
                  levels and features of MULTISERV Service provided by BellSouth
                  to its subscribers. Requests by MCIm for MULTISERV Service and
                  features that are different from what BellSouth provides to
                  its subscribers will be handled under the Bona Fide Request
                  Process. The MULTISERV service provided for resale will meet
                  the following requirements;

                  2.3.1.2 All features and functions of MULTISERV Service,
                  including MULTISERV Management System (CMS), whether

                                                               Attachment II - 3
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  offered under tariff or otherwise, shall be available to MCIm
                  for resale, without any geographic or subscriber class
                  restrictions.

                  2.3.1.3 BellSouth shall make CMS information available to MCIm
                  at the End Office level via an electronic interface as
                  specified in Attachment VIII.

                  2.3.1.4 BellSouth shall provide to MCIm access to information
                  by central office via an electronic interface, relating to all
                  current MULTISERV(R) or MULTISERV-like features and functions
                  offered by BellSouth within ten (10) days of the Effective
                  Date of this Agreement. MCIm can obtain updates to information
                  relating to MULTISERV features and functions as required.

                  2.3.1.5 All service levels and features of MULTISERV Service
                  provided by BellSouth for resale by MCIm shall meet the
                  service requirements set forth in Attachment VIII.

                  2.3.1.6 MCIm may aggregate the MULTISERV local exchange and
                  IntraLATA traffic usage of MCIm subscribers to qualify for
                  volume discounts on the basis of such aggregated usage.

                  2.3.1.7 MCIm may aggregate multiple MCIm subscribers on
                  dedicated access facilities. MCIm may require BellSouth to
                  suppress the need for MCIm subscribers to dial "9" when
                  placing calls outside the MULTISERV System. When dedicated
                  facilities are utilized, BellSouth will provide, upon MCIm's
                  request, station ID or ANI as well as FGD trunking.

                  2.3.1.8 MCIm may use remote call forwarding, or any other
                  method mutually agreed upon, in conjunction with MULTISERV
                  Service to provide service to MCIm local service subscribers
                  residing outside of the geographic territory in which
                  BellSouth provides local exchange service.

                  2.3.1.9 MCIm may purchase any and all levels of MULTISERV
                  Service for resale, without restriction on the maximum number
                  of lines that may be purchased for any one level of service.
                  Where minimum number of line restrictions apply, MCIm may
                  aggregate subscribers to satisfy such restrictions. MCIm shall
                  be permitted to resell MULTISERV to multiple and different
                  subscribers of MCIm for purposes of aggregation; provided,
                  however, that the lines must be aggregated with the
                  MCIm-defined common block.

                                                               Attachment II - 4
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  2.3.1.10 BellSouth shall make available to MCIm for resale
                  intercom calling, at the appropriate discount set forth in
                  Attachment I, among all MCIm subscribers within the same
                  MULTISERV system who utilize resold MULTISERV Service. To the
                  extent that BellSouth offers its own subscribers intercom
                  calling between different MULTISERV systems, BellSouth shall
                  make such calling available to MCIm for resale upon the same
                  terms and conditions at the appropriate discount set forth in
                  Attachment I.

                  2.3.1.11 MCIm may utilize BellSouth's Automatic Route
                  Selection (ARS) service features to provision and route calls
                  from various end users to various Interexchange Carriers (IXC)
                  Networks.

                  2.3.1.12 BellSouth's MULTISERV Service may be used by MCIm to
                  provide Local Service as defined by BellSouth to MCIm's
                  subscribers.

               2.3.2 VOLUNTARY FEDERAL AND STATE SUBSCRIBER FINANCIAL ASSISTANCE
               PROGRAMS

               Local Resale is provided to low-income subscribers, pursuant to
               requirements established by the appropriate state regulatory
               body, include programs such as Voluntary Federal Subscriber
               Financial Assistance Program and Link-Up America. When a
               BellSouth subscriber eligible for the Voluntary Federal
               Subscriber Financial Assistance Program or other similar state
               programs chooses to obtain Local Resale from MCIm, BellSouth
               shall forward all available information regarding such
               subscriber's eligibility to participate in such programs to MCIm
               in accordance with procedures to be mutually established by the
               parties and applicable state and federal law.

               2.3.3 LIFELINE/LINK-UP SERVICE. Lifeline and LinkUp services
               shall be available for resale by MCIm only to those customers who
               meet the qualifications outlined in the means test. The wholesale
               discount shall be applied to the LinkUp and Lifeline services
               purchased by MCIm. BellSouth will then credit MCIm's bill with
               the amount it waives when it serves Lifeline and LinkUp
               customers. BellSouth will then credit MCIm's bill with the
               amount of third party recovery it obtains for that LinkUp and
               Lifeline customer. MCIm agrees to comply with all aspects of the
               FCC's and Mississippi's Orders that implement Lifeline and
               LinkUp services.

                                                               Attachment II - 5
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  2.3.3.1 BellSouth will forward to MCIm, in electronic format,
                  all information regarding a subscriber's program eligibility,
                  status and certification when a BellSouth subscriber currently
                  on any BellSouth telephone assistance program changes service
                  to MCIm as their local exchange carrier. BellSouth will
                  cooperate in obtaining any subsidy associated with a
                  subscriber transfer to MCIm.

               2.3.4 GRANDFATHERED SERVICES. BellSouth shall offer for resale to
               MCIm all grandfathered services. For purposes of this Agreement,
               a grandfathered service is a service that BellSouth offers to
               existing retail subscribers but not to new or different
               subscribers.

               2.3.5 N11 SERVICE

                  2.3.5.1 Until such time as N11 becomes a BellSouth retail
                  service offering and the MPSC authorizes N11 to be made
                  available for resale, N11 is not subject to resale.

                  2.3.5.2 When N11 becomes a retail offering, and the MPSC
                  authorizes N11 to be made available for resale, MCIm shall
                  have the right to resell any N11 service existing as of the
                  Effective Date of the MPSC's authorization. MCIm shall have
                  the right to resell 911 and E911 services.

               2.3.6 CUSTOMER SPECIFIC OFFERINGS INCLUDING CONTRACT SERVICE
               ARRANGEMENTS AND OTHER CUSTOMER SPECIFIC OFFERINGS ("CSAs"). All
               CSAs that are in place as of March 10, 1997, are not required to
               be made available to MCIm by BellSouth for resale purposes. CSAs
               entered into by BellSouth or terminating after March 10, 1997
               shall be subject to resale, at no discount. Upon MCIm's
               identifying to BellSouth a specific CSA, BellSouth shall provide
               MCIm a copy of that CSA within 10 (ten) business days of MCIm's
               request.

                  2.3.6.1 For purposes of thisAgreement, a BellSouth promotion
                  will be considered "short-term" if: the promotion is offered
                  to subscribers for a period of 90 days or less, and is not
                  used to evade the wholesale rate obligation to MCIm, for
                  example, by offering a sequential series of 90 - day or less
                  promotional rates to BellSouth subscribers.

                  2.3.6.2 BellSouth shall make short-term promotions available
                  for resale by MCIm at the lesser of the promotional rate or
                  the

                                                               Attachment II - 6
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  retail rate less the wholesale discount. BellSouth shall make
                  all other promotions available to MCIm at the promotional rate
                  reduced by the wholesale discount rate.

                  2.3.6.3 MCIm shall offer a promotion obtained from BellSouth
                  to customers who would qualify for the promotion if they
                  received it directly from BellSouth; however, MCIm shall
                  otherwise remain free to package and price the resold
                  promotion, other than a short term promotion as defined above,
                  without restriction. A BellSouth promotion for a particular
                  service shall not limit MCIm's ability to obtain that service
                  at the normal rate less the wholesale discount and resell it
                  without regard to subscribers' eligibility for the promotion.

                  2.3.6.4 Special Arrangements shall be available for resale, at
                  the same terms and conditions offered to BellSouth's end
                  users, and in accordance with State and FCC Rules and
                  Regulations. Special Arrangements shall be made available for
                  resale at the price of the Special Arrangement less the
                  wholesale discount.

               2.3.7 DISCOUNT PLANS AND SERVICES. BellSouth shall offer for
               resale all tariffed Discount Plans and Services in accordance
               with State and FCC Rules and Regulations. Discount plans and
               services shall be made available at the tariffed rate less the
               wholesale discount.

               2.3.8 INSIDE WIRE MAINTENANCE SERVICe. BellSouth shall offer for
               resale inside wire maintenance service at the rates set forth in
               Attachment I.

               2.3.9 Pay Phone Service

         BellSouth shall make available to MCIm for resale, at charges set forth
         in Attachment I, all payphone local services, features and
         functionalities that it provides to its own pay phone operations or to
         independent pay phone owners. At a minimum the following Pay Phone
         Services shall be included: Coin Line (currently sold as SmartLine),
         COCOT Line Coin (currently sold as Independent Payphone Provider (IPP)
         Line), and COCOT Line Coinless (currently sold as IPP Line Coinless).
         BellSouth should provide the services and features listed below at the
         same level and standards as BellSouth provides for its own or an
         affiliate's pay phone operations. The following features are currently
         available with these pay phone services and shall be available to MCIm:

         Pay Phone Service

                                                               Attachment II - 7
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  o Billed Number Screening
                  o Originating line screening
                  o Ability to "freeze" PIC selection
                  o One bill per line
                  o Point of demarcation at the Network Interface location
                  o Detailed billing showing all 1+ traffic in EMR format and
                    transferred to MCIm via NDM or whatever industry standard
                    may be developed
                  o Wire Maintenance option
                  o Touchtone service
                  o Option for listed or non-listed numbers
                  o Access to 911 service
                  o One directory per line
                  o Access to ANI information Line and/or station monitoring and
                    diagnostic routines.

                    The following features shall be made available to MCIm when
                    BellSouth provides them to its own pay phone operations or
                    to independent pay phone owners:

                  o Option to block all 1+ calls to international destinations.
                  o IntraLATA Call Timing
                  o Option of one-way or two-way service on line
                  o Originating line screening
                  o MCIm rate tables for local and intraLATA service
                  o Flat rate service based on rate groups
                  o MCIm resale line incoming/outgoing screening
                  o Blocking for 1+900, N11, 976, 7 digit local
                  o Option to block all 1+700 and 1+500 calls
                  o Line side supervision option
                  o Ability to keep existing serving telephone numbers if
                    cutover to MCIm
                  o Far end disconnect recognition
                  o Call timing
                  o Same call restrictions as available on BellSouth phones for
                    interLATA, international, intraLATA, and local calling
                  o Option to have enclosure installed with set
                  o Install the station to at least BellSouth standards
                  o Station or enclosure equipment should only bear the name/
                    brand designated by MCIm on the order form
                  o Provide option for use of "bright station technology
                    including debit cards
                  o Provide revenue, maintenance, collection reports as
                    specified by MCIm on order form on a periodic basis in paper
                    or electronic formation
                  o Blocking of inbound international toll calls
                  o Point of demarcation at the set location
                  o Provide service restoration per MCIm's Performance
                    standards

                                                               Attachment II - 8
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  o Service outage transfers to MCIm help center
                  o Single point of Contact for bills and orders dedicated to
                    Public
                  o Access to MCIm Directory Assistance
                  o Access to MCIm's Network Access Interrupt
                  o Use MCIm branded invoice
                  o Provide all information requested to ensure MCIm can bill
                    for access line
                  o Provide all information requested to ensure MCIm can bill
                    for usage on the line
                  o All calls originating from stations serviced by these lines
                    should be routed to MCI long distance lines
                  o Provide the same monitoring and diagnostic routines on the
                    line as BellSouth would on its own facilities
                  o Ordering per Performance Standards ordered by the Commission
                    or agreed to by the parties
                  o Call Transfer per Performance Standards ordered by the
                  o Commission or agreed to by the parties
                  o Billing per Performance Standards ordered by the Commission
                    or agreed to by the parties
                  o PIC per Performance Standards ordered by the Commission or
                    agreed to by the parties

                  In addition to the above, the following are specifically for
                  coin lines:

                  o Access to all CO intelligence required to perform answer
                    detection, coin collection, coin return, and disconnect*
                  o Option of measured service
                  o Ability to block any 1+ service that cannot be rated by the
                    coin circuits/TSPS/OSPS*
                  o Option to have BellSouth technicians collect, count, and
                    deposit vault contents on behalf of MCIm
                  o Monitor vault contents for slugs and spurious non US
                    currency or theft and notify MCIm of discrepancies

                         2.3.9.1 BellSouth shall offer for resale at a minimum,
                         the following Coin Line features with its resold Coin
                         Line service:

                         Access to all CO intelligence required to perform
                            answer detection, coin collection, coin return, and
                            disconnect
                         Answer Detection
                         Option to block all 1+ calls to international
                            destinations IntraLATA Call Timing
                            Option of one-way or two-way service on line
                            Coin Refund and Repair Referral Service

                                                               Attachment II - 9
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                            The following features shall be made available to
                         MCIm when BellSouth provides them to its own pay phone
                         operations or to independent pay phone owners:

                         Flat Rate Service
                         Originating line screening
                         MCIm rate tables for local and intraLATA service
                         BellSouth Central Office Intelligence for rating and
                         other functions
                         Option of measured service
                         Ability to block any 1+ service that cannot be rated by
                         the coin circuits/ TSPS/OSPS
                         Protect against clip on fraud
                         Protect against blue box fraud

                         2.3.9.2 BellSouth shall offer for resale, at a minimum,
                         the following features with its COCOT Line Coin and
                         COCOT Line Coinless services:

                         Flat rate or measured rate whichever is offered to
                            BellSouth's IPP Customers
                         Ability to keep existing service telephone numbers if
                            cutover to MCIm Resale Line

                            The following features shall be made available to
                         MCIm when BellSouth provides them to its own pay phone
                         operations or to independent pay phone owners:

                         Originating line screening
                         Two-way service option
                         Flat rate service based on rate groups
                         Option of one-way service on the line
                         Option of measured service
                         Ability to keep existing serving telephone numbers if
                            cutover to MCIm resale line incoming/outgoing
                            screening
                         Provision of Information Digit 29
                         Provision of International Toll Denial Recognition Tone

                         2.3.9.3 BellSouth shall offer for resale, at a minimum,
                         the features with its following COCOT Line Coin
                         service:

                         Blocking for 1+ international, 10XXXX1 + international,
                         101XXXX1 + international, 1+900, N111, 976

                                                              Attachment II - 10
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                            The following features shall be made available to
                         MCIm when BellSouth provides them to its own pay phone
                         operations or to independent pay phone owners:

                         Option to block all 1-700 and 1-500 calls Line side
                         supervision option

                         2.3.9.4 BellSouth shall offer for resale, at a minimum,
                         the following features with its COCOT Line Coinless
                         service:

                         Blocking for 1 + international, 10XXXX1 +
                         international, 101XXXX1 + International, 1+900, N11,
                         976, 7 or 10 digit local, 1 + DDD

                         2.3.9.5 BellSouth shall offer for resale, at a minimum,
                         the following features with its SemiPublic Coin
                         service:

                         Ability to keep existing serving telephone numbers if
                         cutover to MCIm
                         Touch-tone Service
                         Option for listed, nonlisted, or non published numbers
                         Provision 911 service
                         Access to ANI information
                         Access to all CO intelligence required to perform
                            answer supervision, coin collect, coin return and
                            disconnect
                         Ability to keep existing serving telephone numbers if
                            cutover to MCIm required to perform answer
                            supervision, collect and refund
                         Far end disconnect recognition
                         Call timing
                         PIC protection for all 1+ local, interLATA, and
                            intraLATA traffic
                         Same call restrictions as available on BellSouth phones
                         for interLATA, international, intraLATA, and local
                         calling
                         One bill per line
                         Detailed billing showing all 1+ traffic in paper or
                         electronic format
                         Option to have enclosure installed with set
                         One directory per line installed
                         Install the station to at least BellSouth standards
                         Ability to block any 1+ service that cannot be rated by
                            the coin circuits

                            The following features shall be made available to
                         MCIm when BellSouth provides them to its own pay phone
                         operations or to independent pay phone owners:

                                                              Attachment II - 11
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  Option to block all 1+ international calls
                  Option of one-way or two-way service Wire Maintenance option
                  Ability to block any 1+ service that cannot be rated by the
                     coin circuits/ TSPS/OSPS
                  Use of MCIm rate tables for local and intraLATA service
                  Option to have BellSouth technicians collect, count, and
                     deposit vault contents on behalf of MCIm
                  Monitor vault contents for slugs and spurious non US currency
                     or theft and notify MCIm of discrepancies
                  Station or enclosure equipment should only bear the name/brand
                     designated by MCIm on the order form
                  Protect against clip on fraud
                  Protect against red box fraud
                  Protect against blue box fraud
                  Provide option for use of "bright" station technology
                     including debit cards
                  Provide revenue, maintenance, collection reports as specified
                     by MCIm on order form on a periodic basis in paper or
                     electronic format
                  Blocking of inbound international calls
                  Point of demarcation at the set location
                  Provide service restoration per MCIm's Performance Standards
                  Service outage transfers to MCIm help center
                  Special screen codes unique to MCIm and/or its subscribers
                  Single point of Contact for bills and orders dedicated to
                  Public Access to MCIm Directory Assistance
                  Access to MCIm's Network Access Interrupt
                  Access to ANI Information
                  Provide all information requested to ensure MCIm can bill for
                     access line
                  Provide all information requested to ensure MCIm can bill for
                     usage on the line
                  All calls originating from stations serviced by these lines
                     should be routed to MCIm lines, except where designated
                  Provide the same monitoring and diagnostic routines on the
                     line as BellSouth would on its own facilities
                  Provide installation intervals per MCIm Performance Standards
                  Ordering per MCIm Performance Standards
                  Call Transfer per MCIm Performance Standards
                  Billing per MCIm Performance Standards
                  PIC per MCIm Performance Standards
                                                              Attachment II - 12
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         2.3.10 VOICE MAIL SERVICE

                  2.3.10.1 MCIm shall have the right to resell BellSouth Voice
                  Mail services.

                  2.3.10.2 Where available to BellSouth's end users, BellSouth
                  shall provide the following features and capabilities to allow
                  for voice mail services:

                  SMDI-E (Station Message Desk Interface-Enhanced)
                  SMDI, Station Message Desk Interface
                  Message Waiting Indicator ("MWI") stutter dialtone and message
                     waiting light feature capabilities
                  CF-B/DA (Call Forward on Busy/Don't Answer)
                  CF/B (Call Forward on Busy)
                  CF/DA (Call Forward Don't Answer)


         2.3.11 HOSPITALITY SERVICE

                  2.3.11.1 BellSouth shall provide all blocking, screening, and
                  all other applicable functions available for hospitality
                  lines.

         2.3.12 TELEPHONE LINE NUMBER CALLING CARDS. Effective thirty (30) days
         after the date of an end-user's subscription to MCIm service or within
         24 hours after MCIm has notified BellSouth that it has replaced the
         subscriber's calling card, whichever is earlier, BellSouth will
         terminate its existing telephone line number-based calling cards and
         remove any BellSouth-assigned Telephone Line Calling Card Number
         (including area code) ("TLN") from the LIDB. MCIm may issue a new
         telephone calling card to such subscriber, utilizing the same TLN, and
         MCIm shall have the right to enter such TLN in LIDB for calling card
         validation purposes via the service order process. BellSouth will
         direct-bill each subscriber on the subscriber's final bill. BellSouth
         will coordinate the disconnection of subscriber's calling cards with
         MCIm to ensure that there is no time that a subscriber is without a
         calling card.

SECTION 3. ADVANCED INTELLIGENT NETWORK

               3.1.1 MCIm may purchase at the discount set forth in Attachment I
               any Advanced Intelligent Network (AIN") Telecommunications
               Services which BellSouth offers at retail, for resale to
               subscribers who are not carriers.

                                                              Attachment II - 13
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

SECTION 4. SERVICE FUNCTIONS

         4.1 BellSouth shall provide MCIm with theinformation MCIm will need to
         certify subscribers as exempt from charges (including taxes), or
         eligible for reduced charges associated with providing services,
         including but not limited to handicapped individuals, and certain
         governmental bodies and public institutions and shall not bill MCIm for
         such services.

         4.2 BellSouth shall provide MCIm with appropriate notification of all
         area transfers with line level detail one hundred twenty (120) days
         before service transfer, and will also notify MCIm within one hundred
         twenty (120) days before such change of any LATA boundary changes or
         within the timeframe required by an approving regulatory body, if any.

         4.3 BellSouth will work cooperatively with MCIm in practices and
         procedures regarding the handling of law enforcement and service
         annoyance calls.


                                                              Attachment II - 14
<PAGE>

        MCIm - BellSouth Mississippi Interconnection Agreement Attachment


                                TABLE OF CONTENTS

                                 ATTACHMENT III
                                NETWORK ELEMENTS

Section 1.        Introduction                                         III - 1

Section 2.        Unbundled Network Elements                           III - 1

Section 3.        Standards for Network Elements                       III - 3

Section 4.        Loop                                                 III - 4

Section 5.        Left Blank Intentionally

Section 6.        Left Blank Intentionally

Section 7.        Local Switching                                      III - 18

Section 8.        Operator Systems                                     III - 26

Section 9.        Common Transport                                     III - 26

Section 10.       Dedicated Transport                                  III - 29

Section 11.       Signaling Link Transport                             III - 39

Section 12.       Signaling Transfer Points (STPs)                     III - 41

Section 13.       Service Control Points/Databases                     III - 46

Section 14.       Tandem Switching                                     III - 58

Section 15.       Additional Requirements                              III - 61

Section 16.       Basic 911 and E911                                   III - 102

Section 17.       Directory Assistance Data                            III - 102

                                                              Attachment III - i
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                                 ATTACHMENT III

                                NETWORK ELEMENTS

SECTION 1.  INTRODUCTION

BellSouth shall provide unbundled Network Elements in accordance with this
Agreement, FCC Rules and Regulations. The price for each Network Element is set
forth in Attachment I of this Agreement. Except as otherwise set forth in this
Attachment, MCIm may order Network Elements as of the Effective Date.

SECTION 2.  UNBUNDLED NETWORK ELEMENTS

         2.1  BellSouth shall offer Network Elements to MCIm on an unbundled
         basis on rates, terms and conditions that are just, reasonable, and
         non-discriminatory in accordance with the terms and conditions of this
         Agreement.

         2.2  BellSouth shall permit MCIm to connect MCIm's facilities or
         facilities provided to MCIm by third parties with each of BellSouth's
         unbundled Network Elements at any point designated by MCIm that is
         Technically Feasible.

         2.3  MCIm may use one or more Network Elements to provide any feature,
         function, capability, or service option that such Network Element(s) is
         capable of providing or any feature, function, capability, or service
         option that is described in the technical references identified herein;
         provided, however, that when MCIm recombines unbundled BellSouth
         Elements to create services identical to BellSouth's retail offerings,
         the prices charged to MCIm for the rebundled services shall be computed
         at BellSouth's retail price less the wholesale discount rate, and
         shall be offered under the same terms and conditions as BellSouth
         offers the service. MCIm will be deemed to be "recombining unbundled
         elements to create services identical to BellSouth's retail offerings"
         when the service offered by MCIm contains the functions, features and
         attributes of a retail service offering that is the subject of a
         properly filed and approved BellSouth tariff. Furthermore, services
         offered by MCIm shall not be considered "identical" when MCIm utilizes
         its own switching or other substantive functionality or capability in
         combination with unbundled Elements in order to produce a service
         offering. For example, MCIm's provisioning of purely ancillary
         functions or capabilities, such as operator services, Caller ID, Call
         Waiting, etc., in combination with unbundled BellSouth network
         elements, shall not constitute substantive functionality or capability
         for purposes of determining whether MCIm is providing services
         identical to a BellSouth retail offering.

                                                              Attachment III - 1
<PAGE>

           MCIm-BellSouth Mississippi Interconnection Agreement

                  2.3.1    MCIm may, at its option, designate any Technically
                  Feasible method of access to unbundled elements, including
                  access methods currently or previously in use.

         2.4  Subject to Section 2.3, BellSouth shall offer each Network Element
         individually and in combination with any other Network Element or
         Network Elements in order to permit MCIm to provide Telecommunications
         Services to its subscribers.

         2.5  For each Network Element, BellSouth shall provide a demarcation
         point (e.g., at a Digital Signal Cross Connect, Light Guide Cross
         Connect panel or a Main Distribution Frame) and, if necessary, access
         to such demarcation point, which MCIm agrees is suitable. However,
         where BellSouth provides combined Network Elements at MCIm's
         direction, no demarcation point shall exist between such contiguous
         Network Elements.

         2.6  With respect to Network Elements and services in existence as of
         the Effective Date of this Agreement, charges in Attachment I are
         inclusive and no other charges apply, including but not limited to any
         other consideration for connecting any Network Element(s) with other
         Network Element(s). BellSouth and MCIm agree to attempt in good faith
         to resolve any alleged errors or omissions in Attachment I.

         2.7  This Attachment describes the initial set of Network Elements
         which MCIm and BellSouth have identified as of the effective date of
         this agreement:

                  Loop
                  Network Interface Device
                  Distribution (Subject to BFR process in Part A or this
                  Agreement)
                  Local Switching
                  Operator Systems
                  Common Transport
                  Dedicated Transport
                  Signaling Link Transport
                  Signaling Transfer Points
                  Service Control Points/Databases
                  Tandem Switching
                  911 Directory Assistance
                  Loop
                  Concentrator/Multiplexer (Subject to BFR process in Part A of
                      this Agreement)
                  AIN Capabilities

                                                              Attachment III - 2
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         2.8  MCIm and BellSouth agree that the Network Elements identified in
         this Attachment are not all possible Network Elements.

         2.9  MCIm may identify additional or revised Network Elements as
         necessary to provide telecommunications services to its subscribers, to
         improve network or service efficiencies or to accommodate changing
         technologies, subscriber demand, or other requirements.

         MCIm will request such Network Elements in accordance with the bona
         fide request process described in Section 24 of Part A. Additionally,
         if BellSouth provides any Network Element that is not identified in
         this Agreement, to itself, to its own subscribers, to a BellSouth
         Affiliate or to any other entity, BellSouth shall make available the
         same Network Element to MCIm on terms and conditions no less favorable
         to MCIm than those provided to itself or to any other party, at charges
         set forth in Attachment I.

SECTION 3.  STANDARDS FOR NETWORK ELEMENTS

         3.1  Each Network Element shall be furnished at a service level equal
         to or better than the requirements set forth in the technical
         references referenced in the following, as well as any performance or
         other requirements, identified herein. In the event Bell Communications
         Research, Inc. ("Bellcore"), or industry standard (e.g., American
         National Standards Institute ("ANSI") technical reference or a more
         recent version of such reference sets forth a different requirement,
         MCIm may elect, where Technically Feasible, that such standard shall
         apply.

         3.2  If one or more of the requirements set forth in this Agreement
         with respect to BellSouth' s obligations to MCI are in conflict, MCIm
         shall elect which requirement shall apply.

         3.3  Each Network Element provided by BellSouth to MCIm shall be at
         least equal in the quality of design, performance, features, functions,
         capabilities and other characteristics, including but not limited to
         levels and types of redundant equipment and facilities for power,
         diversity and security, that BellSouth provides to itself, BellSouth's
         own subscribers, to a BellSouth Affiliate or to any other entity.

                  3.3.1    BellSouth shall provide to MCIm, upon request,
                  engineering, design, performance and other network data
                  sufficient for MCIm to determine that the requirements of this
                  Section 3 are being met. In the event that such data indicates
                  that the requirements of this Section 3 are not being met,
                  BellSouth shall, within ten (10) days, cure any design,
                  performance or other deficiency, or, if the failure is not

                                                              Attachment III - 3
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  susceptible to cure within ten (10) days shall commence and
                  continue its best efforts to correct such failure as soon as
                  possible, and provide new data sufficient for MCIm to
                  determine that such deficiencies have been cured.

                  3.3.2    BellSouth agrees to work cooperatively with MCIm to
                  provide Network Elements that will meet MCIm's needs in
                  providing services to its subscribers.

         3.4  Unless otherwise requested by MCIm, each Network Element and the
         connections between Network Elements provided by BellSouth to MCIm
         shall be made available to MCIm on a priority basis, at any Technically
         Feasible point, that is equal to or better than the priorities that
         BellSouth provides to itself, BellSouth's own BellSouth subscribers, to
         a BellSouth Affiliate or to any other entity.

SECTION 4.  LOOP

         4.1  DEFINITION

                  4.1.1    A loop is a transmission facility between a
                  distribution frame [cross-connect], or its equivalent, in a
                  BellSouth central office or wire center, and the network
                  interface device at a subscriber' s premises, to which MCIm's
                  granted exclusive use. This includes, but is not limited to
                  two-wire and four-wire analog voice-grade loops, and two-wire
                  and four-wire loops that are conditioned to transmit the
                  digital signals needed to provide ISDN, ADSL, HDSL, and
                  DS1-level signals. A loop may be composed of the following
                  components:

                           Loop Concentrator / Multiplexer
                           Loop Feeder
                           Network Interface Device (NID)
                           Distribution

                  4.1.2    If BellSouth uses Integrated Digital Loop Carrier
                  (IDLCs) systems to provide the local loop, BellSouth will make
                  alternate arrangements, equal in quality, to permit MCIm to
                  order a contiguous unbundled local loop at no additional cost
                  to MCIm except where the absence of existing facilities
                  necessitates special construction.

         4.2. TECHNICAL REQUIREMENTS

         Subdivided to each component as detailed below.

         4.3  INTERFACE REQUIREMENTS

                                                              Attachment III - 4
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         Subdivided to each component as detailed below.

         4.4  LOOP COMPONENTS

                  4.4.1    LOOP CONCENTRATOR/MULTIPLEXER

                           4.4.1.1  DEFINITION:

                                    4.4.1.1.1  The Loop Concentrator/Multiplexer
                                    is the Network Element that:(1) aggregates
                                    lower bit rate or bandwidth signals to
                                    higher bit rate or bandwidth signals
                                    (multiplexing); (2) disaggregates higher bit
                                    rate or bandwidth signals to lower bit rate
                                    or bandwidth signals (demultiplexing); (3)
                                    aggregates a specified number of signals or
                                    channels to fewer channels (concentrating);
                                    (4)performs signal conversion, including
                                    encoding of signals (e.g., analog to digital
                                    and digital to analog signal conversion);
                                    and (5) in some instances performs
                                    electrical to optical (E/O) conversion. Any
                                    request by MCIm for unbundling the Loop
                                    Concentrator/Multiplexer will be made
                                    pursuant to the Bona Fide Request Process
                                    identified in Part A of this Agreement.

                                    4.4.1.1.2  The Loop Concentrator/Multiplexer
                                    function may be provided through a Digital
                                    Loop Carrier (DLC) system, channel bank,
                                    multiplexer or other equipment at which
                                    traffic is encoded and decoded, multiplexed
                                    and demultiplexed, or concentrated.

                           4.4.1.2  TECHNICAL REQUIREMENTS

                                    4.4.1.2.1  The Loop Concentrator/Multiplexer
                                    shall be capable of performing its functions
                                    on the signals for the following services,
                                    including but not limited to, (as needed by
                                    MCIm to provide end-to-end service
                                    capability to its subscriber):

                                         4.4.1.2.1.1  two-wire & four-wire
                                         analog voice grade loops;

                                         4.4.1.2.1.2  two-wire & four-wire loops
                                         that are conditioned to transmit the
                                         digital signals needed to provide
                                         services such as ISDN, ADSL, HDSL, and
                                         DS1-level signals.

                                                              Attachment III - 5
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         4.4.1.2.1.3  4-wire digital data
                                         (2.4Kbps through 64Kbps and n times
                                         64Kbps (where n (less than) 24);

                                         4.4.1.2.1.4  DS3 rate private lines;

                                         4.4.1.2.1.5 Optical SONET rate private
                                         lines;

                                    4.4.1.2.2  The Loop Concentrator/Multiplexer
                                    shall perform the following functions as
                                    appropriate:

                                         4.4.1.2.2.1  Analog to digital signal
                                         conversion of both incoming and
                                         outgoing (upstream and downstream)
                                         analog signals;

                                         4.4.1.2.2.2 Multiplexing of the
                                         individual digital signals up to higher
                                         transmission bit rate signals (e.g.,
                                         DS0, DS1, DS3, or optical SONET rates)
                                         for transport to the BellSouth central
                                         office through the Loop Feeder; and

                                         4.4.1.2.2.3 Concentration of end-user
                                         subscriber signals onto fewer channels
                                         of a Loop Feeder (The concentration
                                         ratio shall be as specified by MCIm).

                                    4.4.1.2.3  BellSouth shall provide power for
                                    the Loop Concentrator /Multiplexer, through
                                    a non-interruptible source if the function
                                    is performed in a central office, or from a
                                    commercial AC power source with battery
                                    backup if the equipment is located outside a
                                    central office. Such power shall also adhere
                                    to the requirements stated herein.

                                    4.4.1.2.4  The Loop Concentrator/Multiplexer
                                    shall be provided to MCIm in accordance with
                                    the following Technical References:

                                         4.4.1.2.4.1  Bellcore TR-NWT-000057,
                                         Functional Criteria for Digital Loop
                                         Carrier Systems, Issue 2, January 1993.

                                         4.4.1.2.4.2  Bellcore TR-NWT-000393,
                                         Generic Requirements for ISDN Basic
                                         Access Digital Subscriber Lines.

                                                              Attachment III - 6
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         4.4.1.2.4.3  ANSI T1.106 - 1988,
                                         American National Standard for
                                         Telecommunications - Digital Hierarchy
                                         - Optical Interface Specifications
                                         (Single Mode).

                                         4.4.1.2.4.4  ANSI T1.105-1995,
                                         American National Standard for
                                         Telecommunications - Synchronous
                                         Optical Network (SONET) - Basic
                                         Description including Multiplex
                                         Structure, Rates and Formats.

                                         4.4.1.2.4.5  ANSI T1.102-1993, American
                                         National Standard for
                                         Telecommunications - Digital Hierarchy
                                         - Electrical Interfaces.

                                         4.4.1.2.4.6  ANSI T1.403-1989, American
                                         National Standard for
                                         Telecommunications - Carrier to
                                         Subscriber Installation, DS1 Metallic
                                         Interface Specification.

                                         4.4.1.2.4.7  Bellcore GR-253-CORE,
                                         Synchronous Optical Network Systems
                                         (SONET), Common Generic Criteria..

                                         4.4.1.2.4.8  Bellcore TR-TSY-000008,
                                         Digital Interface Between the SLC 96
                                         Digital Loop Carrier System and a Local
                                         Digital Switch, Issue 2, August 1987.

                                         4.4.1.2.4.9  Bellcore TR-NWT-000303,
                                         Integrated Digital Loop Carrier System
                                         Generic Requirements, Objectives and
                                         Interface, Issue 2, December 1992; Rev.
                                         1, December 1993; Supplement 1,
                                         December 1993.

                                         4.4.1.2.4.10 Bellcore TR-TSY-000673,
                                         Operations Systems Interface for an
                                         IDLC System, (LSSGR) FSD 20-02-2100,
                                         Issue 1, September 1989.

                                         4.4.1.2.4.11 Bellcore Integrated
                                         Digital Loop Carrier System Generic
                                         Requirements, Objectives and Interface,
                                         GR-303-CORE, Issue 1, September 1995.

                                                              Attachment III - 7
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           4.4.1.3  REQUIREMENTS FOR AN INTELLIGENT LOOP
                           CONCENTRATOR/ MULTIPLEXER

                                    4.4.1.3.1  In addition to the basic
                                    functions described above for the Loop
                                    Concentrator/Multiplexer, the Intelligent
                                    Loop Concentrator/Multiplexer (IC/M)shall
                                    provide facility grooming, facility test
                                    functions, format conversion and signaling
                                    conversion as appropriate.

                                    4.4.1.3.2  The underlying equipment that
                                    provides such IC/M function shall
                                    continuously monitor protected circuit packs
                                    and redundant common equipment.

                                    4.4.1.3.3  The underlying equipment that
                                    provides such IC/M function shall
                                    automatically switch to a protection circuit
                                    pack on detection of a failure or
                                    degradation of normal operation.

                                    4.4.1.3.4  The underlying equipment that
                                    provides such IC/M function shall be
                                    equipped with a redundant power supply or a
                                    battery back-up.

                                    4.4.1.3.5  At MCIm's option, BellSouth shall
                                    provide MCIm with real time performance
                                    monitoring and alarm data on IC/M elements
                                    that may affect MCIm's traffic. This
                                    includes IC/M hardware alarm data and
                                    facility alarm data on the underlying device
                                    that provides such IC/M function.

                                    4.4.1.3.6  At MCIm's option, BellSouth shall
                                    provide MCIm with real time ability to
                                    initiate tests on the underlying device that
                                    provides such IC/M function integrated test
                                    equipment as well as other integrated
                                    functionality for routine testing and fault
                                    isolation.

                           4.4.1.4  INTERFACE REQUIREMENTS

                                    4.4.1.4.1  The Loop Concentrator/Multiplexer
                                    shall meet the following interface
                                    requirements, as appropriate for the
                                    configuration that MCIm designates:

                                    4.4.1.4.2  The Loop Concentrator/Multiplexer
                                    shall provide an analog voice frequency
                                    copper twisted pair interface at the serving
                                    wire center, as described in the references
                                    in Section 4.4.1.2.4.

                                                              Attachment III - 8
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    4.4.1.4.3  The Loop Concentrator/Multiplexer
                                    shall provide digital 4-wire electrical
                                    interfaces at the serving wire center, as
                                    described in the references in Section
                                    4.4.1.2.4.

                                    4.4.1.4.4  The Loop Concentrator/Multiplexer
                                    shall provide optical SONET interfaces at
                                    rates of OC-3, OC-12, OC-48, and OC-N, N as
                                    described in the references in Section
                                    4.4.1.2.4.

                                    4.4.1.4.5  The Loop Concentrator/Multiplexer
                                    shall provide the Bellcore TR-303 DS1 level
                                    interface at the serving wire center. Loop
                                    Concentrator/ Multiplexer shall provide
                                    Bellcore TR-08 modes 1&2 DS1 interfaces when
                                    designated by MCIm. Such interface
                                    requirements are specified in the references
                                    in Section 4.4.1.2.4.

                           4.4.1.5  The Intelligent Loop
                           Concentrator/Multiplexer shall be provided to MCIm in
                           accordance with the Technical References set forth in
                           Sections 4.4.1.2.4.8 through 4.4.1.2.4.11 above.

                  4.4.2    LOOP FEEDER

                           4.4.2.1  DEFINITION:

                                    4.4.2.1.1  The Loop Feeder provides
                                    connectivity between (1) a Feeder
                                    Distribution Interface (FDI) associated with
                                    Loop Distribution and a termination point
                                    appropriate for the media in a central
                                    office, or (2) a Loop
                                    Concentrator/Multiplexer provided in a
                                    remote terminal and a termination point
                                    appropriate for the media in a central
                                    office. BellSouth shall provide MCIm
                                    physical access to the FDI, and the right to
                                    connect, the Loop Feeder to the FDI.

                                    4.4.2.1.2  The physical medium of the Loop
                                    Feeder may be copper twisted pair, or single
                                    or multi-mode fiber or other technologies as
                                    designated by MCIm. In certain cases, MCIm
                                    will require a copper twisted pair loop even
                                    in instances where the medium of the Loop
                                    Feeder for services that BellSouth offers is
                                    other than a copper facility.

                           4.4.2.2  REQUIREMENTS FOR LOOP FEEDER

                                                              Attachment III - 9
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    4.4.2.2.1  The Loop Feeder shall be capable
                                    of transmitting analog voice frequency,
                                    basic rate ISDN, digital data, or analog
                                    radio frequency signals as appropriate.

                                    4.4.2.2.2  BellSouth shall provide
                                    appropriate power for all active elements in
                                    the Loop Feeder. BellSouth will provide
                                    appropriate power from a central office
                                    source, or from a commercial AC source with
                                    rectifiers for AC to DC conversion and
                                    8-hour battery back-up when the equipment is
                                    located in an outside plant Remote Terminal
                                    (RT).

                           4.4.2.3  ADDITIONAL REQUIREMENTS FOR SPECIAL COPPER
                           LOOP FEEDER MEDIUM

                           In addition to requirements set forth in Section 4.2
                           (above), MCIm may require BellSouth to provide copper
                           twisted pair Loop Feeder which is unfettered by any
                           intervening equipment (e.g. filters, load coils, and
                           range extenders), so that MCIm can use these Loop
                           Feeders for a variety of services by attaching
                           appropriate terminal equipment at the ends.

                           4.4.2.4  ADDITIONAL TECHNICAL REQUIREMENTS FOR DS1
                           CONDITIONED LOOP FEEDER

                           In addition to the requirements set forth in Section
                           4.4.2.2 above, MCIm may designate that the Loop
                           Feeder be conditioned to transport a DS1 signal. The
                           requirements for such transport are defined in the
                           references below in Section 4.4.2.6.

                           4.4.2.5  ADDITIONAL TECHNICAL REQUIREMENTS FOR
                           OPTICAL LOOP FEEDER

                           In addition to the requirements set forth in Section
                           4.4.2.2 above, MCIm may designate that Loop Feeder
                           will transport DS3 and OCn (where n is defined in the
                           technical reference in Section 4.4.1.2.4.4. The
                           requirements for such transport are defined in the
                           references below in Section 4.4.2.6.

                           4.4.2.6  BellSouth shall offer Loop Feeder in
                           accordance with the requirements set forth in the
                           following Technical References:

                                                             Attachment III - 10
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    4.4.2.6.1  Bellcore Technical Requirement
                                    TR-NWT-000499, Issue 5, December 1993,
                                    section 7 for DS1 interfaces; and,

                                    4.4.2.6.2  Bellcore TR-NWT-000057,
                                    Functional Criteria for Digital Loop Carrier
                                    Systems, Issue 2, January 1993.

                                    4.4.2.6.3  Bellcore TR-NWT-000393, Generic
                                    Requirements for ISDN Basic Access Digital
                                    Subscriber Lines.

                                    4.4.2.6.4  ANSI T1.106-1988, American
                                    National Standard for Telecommunications -
                                    Digital Hierarchy - Optical Interface
                                    Specifications (Single Mode).

                                    4.4.2.6.5  ANSI T1.105-1995, American
                                    National Standard for Telecommunications -
                                    Synchronous Optical Network (SONET) - Basic
                                    Description including Multiplex Structure,
                                    Rates and Formats.

                                    4.4.2.6.6  ANSI T1.102-1993, American
                                    National Standard for Telecommunications -
                                    Digital Hierarchy - Electrical Interfaces.

                                    4.4.2.6.7  ANSI T1.403-1989, American
                                    National Standard for Telecommunications -
                                    Carrier to Subscriber Installation, DS1
                                    Metallic Interface Specification

                                    4.4.2.6.8  Bellcore GR-253-CORE, Synchronous
                                    Optical Network Systems (SONET), Common
                                    Generic Criteria.

                           4.4.2.7  INTERFACE REQUIREMENTS

                                    4.4.2.7.1  The Loop Feeder point of
                                    termination (POT) within a BellSouth central
                                    office will be as follows:

                                         4.4.2.7.1.1  Copper twisted pairs shall
                                         terminate on the MDF;

                                         4.4.2.7.1.2  DS1 Loop Feeder shall
                                         terminate on a DSX1, DCS1/0 or DCS3/1;
                                         and

                                         4.4.2.7.1.3  Fiber Optic cable shall
                                         terminate on a LGX.

                                                             Attachment III - 11
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    4.4.2.7.2  Loop Feeder shall be equal to or
                                    better than each of the applicable interface
                                    requirements set forth in the following
                                    technical references:

                                         4.4.2.7.2.1  Bellcore TR-TSY-000008,
                                         Digital Interface Between the SLC 96
                                         Digital Loop Carrier System and a Local
                                         Digital Switch, Issue 2. August 1987.

                                         4.4.2.7.2.2  Bellcore TR-NWT-000303,
                                         Integrated Digital Loop Carrier System
                                         Generic Requirements, Objectives and
                                         Interface, Issue 2, December 19921-
                                         Rev. 1, December 1993-1 Supplement 1,
                                         December 1993.

                                         4.4.2.7.2.3  Bellcore Integrated
                                         Digital Loop Carrier System Generic
                                         Requirements, Objectives and Interface,
                                         GR-303-CORE, Issue 1, September 1995.

         4.5  NETWORK INTERFACE DEVICE

                  4.5.1    DEFINITION:

                           4.5.1.1  The Network Interface Device (NID) is a
                           single-line termination device or that portion of a
                           multiple-line termination device required to
                           terminate a single line or circuit. The function of
                           the NID is to establish the network demarcation point
                           between a carrier and its subscriber. The NID
                           features two independent chambers or divisions which
                           separate the service provider's network from the
                           subscriber's inside wiring. Each chamber or division
                           contains the appropriate connection points or posts
                           to which the service provider, and the subscriber
                           each make their connections.

                           4.5.1.2  With respect to multiple-line termination
                           devices, MCIm shall specify the quantity of NIDs it
                           requires within such device.

                           4.5.1.3  Figure 1 shows a schematic of a NID.

                                                             Attachment III - 12
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

[GRAPHIC OMITTED]

                      FIGURE 1 - NETWORK INTERFACE DEVICE

                  4.5.2    TECHNICAL REQUIREMENTS

                           4.5.2.1  The BellSouth Network Interface Device shall
                           provide a clean, accessible point of connection for
                           the inside wiring for MCIm's Distribution Media via
                           MCIm's NID and shall maintain a connection to ground
                           that meets the requirements set forth below.

                           4.5.2.2  The NID shall be capable of transferring
                           electrical analog or digital signals between the
                           subscriber's inside wiring for MCIm's Distribution
                           Media via MCIm's NID.

                           4.5.2.3  All NID posts or connecting points shall be
                           in place, secure, usable and free of any rust or
                           corrosion. The protective ground connection shall
                           exist and be properly installed. The ground wire
                           shall be free of rust or corrosion and have
                           continuity relative to ground.

                           4.5.2.4  The NID shall be capable of withstanding all
                           normal local environmental variations.

                           4.5.2.5  Where the NID is not located in a larger,
                           secure cabinet or closet, the NID shall be protected
                           from physical vandalism. The NID shall be physically
                           accessible to MCIm designated personnel. In cases
                           where entrance to the subscriber premises is required
                           to give access to the NID, MCIm shall obtain entrance
                           permission directly from the subscriber.

                                                             Attachment III - 13
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           4.5.2.6  BellSouth shall offer the NID together with,
                           and separately from the Distribution Media component
                           of Loop Distribution.

                  4.5.3    INTERFACE REQUIREMENTS

                           4.5.3.1  The NID shall be the interface to
                           subscribers' premises wiring for all loop
                           technologies.

                           4.5.3.2  The NID shall be equal to or better than all
                           of the industry standards for NIDs set forth in the
                           following technical references:

                                    4.5.3.2.1  Bellcore Technical Advisory
                                    TA-TSY-000120 "Subscriber Premises or
                                    Network Ground Wire";

                                    4.5.3.2.2  Bellcore Generic Requirement
                                    GR-49-CORE "Generic Requirements for Outdoor
                                    Telephone Network Interface Devices";

                                    4.5.3.2.3  Bellcore Technical Requirement
                                    TR-NWT-00239 "Indoor Telephone Network
                                    Interfaces";

                                    4.5.3.2.4  Bellcore Technical Requirement
                                    TR-NWT-000937 "Generic Requirements for
                                    Outdoor and Indoor Building Entrance"; and,

                                    4.5.3.2.5  Bellcore Technical Requirement
                                    TR-NWT-0001 3 "Generic Requirements for
                                    Network Inside Wiring."

                  4.5.4    Responsibilities of The Parties for Conditions of
                  Access And Attachment To NIDs. BellSouth shall allow MCIm to
                  access the customer's inside wiring. Such access may take
                  place through either of the following: 1) allow MCIm to use
                  any existing capacity on BellSouth's NID; or, 2) allow MCIm
                  to connect its NID to BellSouth's NID in adherence with FCC
                  rules regarding a NID to NID arrangement.

         4.6  DISTRIBUTION

                  4.6.1    DEFINITION:

                           4.6.1.1  Distribution is a Network Element that
                           provides connectivity between the NID component of
                           Loop Distribution and the terminal block on the
                           subscriber-side of a Feeder

                                                             Attachment III - 14
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           Distribution Interface (FDI). The FDI is a device
                           that terminates the Distribution Media and the Loop
                           Feeder, and cross-connects them in order to provide a
                           continuous transmission path between the NID and a
                           telephone company central office. There are three
                           basic types of feeder-distribution connection: (I)
                           multiple (splicing of multiple distribution pairs
                           onto one feeder pair); (ii) dedicated ("home run");
                           and (iii) interfaced ("cross-connected"). While older
                           plant uses multiple and dedicated approaches, newer
                           plant and all plant that uses DLC or other pair-gain
                           technology necessarily uses the interfaced approach.
                           The feeder-distribution interface (FDI) in the
                           interfaced design makes use of a manual
                           cross-connection, typically housed inside an outside
                           plant device ("green box") or in a vault or manhole.
                           Any request by MCIm for unbundling of Distribution
                           Media will be made pursuant to the Bona Fide Request
                           Process identified in Part A of this Agreement.

                           4.6.1.2  The Distribution may be copper twisted pair,
                           coax cable, single or multi-mode fiber optic cable or
                           other technologies. A combination that includes two
                           or more of these media is also possible. In certain
                           cases, MCIm shall require a copper twisted pair
                           Distribution even in instances where the Distribution
                           for services that BellSouth offers is other than a
                           copper facility.

                  4.6.2    REQUIREMENTS FOR ALL DISTRIBUTION

                           4.6.2.1  Distribution shall be capable of
                           transmitting signals for the following services (as
                           requested by MCIm):

                                    4.6.2.1.1  Two-wire & four-wire analog voice
                                    grade loops;

                                    4.6.2.1.2  Two-wire & four-wire loops that
                                    are conditioned to transmit the digital
                                    signals needed to provide services such as
                                    ISDN, ADSL, HDSL, and DS1-level signals.

                           4.6.2.2  Distribution shall transmit all signaling
                           messages or tones. Where the Distribution includes
                           any active elements that terminate any of the
                           signaling messages or tones, these messages or tones
                           shall be reproduced by the Distribution at the
                           interfaces to an adjacent Network Element in a format
                           that maintains the integrity of the signaling
                           messages or tones.

                                                             Attachment III - 15
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           4.6.2.3  Distribution shall support functions
                           associated with provisioning, maintenance and testing
                           of the Distribution itself, as well as provide
                           necessary access to provisioning, maintenance and
                           testing functions for Network Elements to which it is
                           associated.

                           4.6.2.4  Where possible, Distribution shall provide
                           performance monitoring of the Distribution itself, as
                           well as provide necessary access for performance
                           monitoring for Network Elements to which it is
                           associated.

                           4.6.2.5 Distribution shall be equal to or better than
                           all of the applicable requirements set forth in the
                           following technical references:

                                    4.6.2.5.1  Bellcore TR-TSY-000057,
                                    "Functional Criteria for Digital Loop
                                    Carrier Systems", and,

                                    4.6.2.5.2  Bellcore TR-NWT-000393, "Generic
                                    Requirements for ISDN Basic Access Digital
                                    Subscriber Lines."

                           4.6.2.6  BellSouth shall provide MCIm with physical
                           access to, and the right to connect to, the FDI.

                           4.6.2.7  BellSouth shall offer Distribution together
                           with, and separately from the NID component of Loop
                           Distribution.

                  4.6.3    ADDITIONAL REQUIREMENTS FOR SPECIAL COPPER
                  DISTRIBUTION

                  In addition to Distribution that supports the requirements in
                  Section 6.2. may designate Distribution to be copper twisted
                  pair which are unfettered by any intervening equipment (e.g.,
                  filters, load coils, range extenders) so that MCIm can use
                  these loops for a variety of services by attaching appropriate
                  terminal equipment at the ends.

                  4.6.4    ADDITIONAL REQUIREMENTS FOR FIBER DISTRIBUTION

                  Fiber optic cable Distribution shall be capable of
                  transmitting signals for the following services in addition to
                  the ones under Section 6.2.1 above:

                           4.6.4.1  DS3 rate private line service;

                                                             Attachment III - 16
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           4.6.4.2  Optical SONET OCn rate private lines (where
                           n is defined in the technical reference in Section
                           4.4.1.2.4.4; and

                           4.6.4.3  Analog Radio Frequency based services (e.g.,
                           Cable Television (CATV)).

                  4.6.5    ADDITIONAL REQUIREMENTS FOR COAXIAL CABLE
                  DISTRIBUTION

                  Coaxial Cable (coax) Distribution shall be capable of
                  transmitting signals for the following services in addition to
                  the ones under Section 6.2.1 above:

                           4.6.5.1  Broadband data, either one way or
                           bi-directional, symmetric or asymmetric, at rates
                           between 1.5 Mb/s and 45 Mb/s; and

                           4.6.5.2  Analog Radio Frequency based services (e.g.,
                           CATV).

                  4.6.6    INTERFACE REQUIREMENTS

                           4.6.6.1  Signal transfers between the Distribution
                           and the NID and an adjacent Network Element shall
                           have levels of degradation that are within the
                           performance requirements set forth in Section 15.2 of
                           this Attachment III.

                           4.6.6.2  Distribution shall be equal to or better
                           than each of the applicable interface requirements
                           set forth in the following technical references:

                                    4.6.6.2.1  Bellcore TR-NWT-000049, "Generic
                                    Requirements for Outdoor Telephone Network
                                    Interface Devices," Issued December 1,1994;

                                    4.6.6.2.2  Bellcore TR-NWT-000057,
                                    "Functional Criteria for Digital Loop
                                    Carrier Systems," Issued January 2, 1993;

                                    4.6.6.2.3  Bellcore TR-NWT-000393, "Generic
                                    Requirements for ISDN Basic Access Digital
                                    Subscriber Lines";

                                    4.6.6.2.4  Bellcore TR-NWT-000253, SONET
                                    Transport Systems: Common Criteria (A module
                                    of TSGR, FR-NWT- 000440), Issue 2, December
                                    1991;

                                                             Attachment III - 17
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

SECTION 5 - Left blank intentionally

SECTION 6 - Left blank intentionally

SECTION 7 - LOCAL SWITCHING

         7.1  DEFINITION

                  7.1.1    Local Switching is the Network Element that provides
                  the functionality required to connect the appropriate lines or
                  trunks wired to the Main Distributing Frame (MDF) or Digital
                  Cross Connect (DSX) panel to a desired line or trunk. The
                  desired connection path for each call type will vary by
                  subscriber and will be specified by MCIm as a routing scenario
                  that will be implemented in advance as part of or after the
                  purchases of the unbundled local switching. Such functionality
                  shall include all of the features, functions, and capabilities
                  that the underlying BellSouth switch that is providing such
                  Local Switching function is capable of providing, including
                  but not limited to: line signaling and signaling software,
                  digit reception, dialed number translations, call screening,
                  routing, recording, call supervision, dial tone, switching,
                  telephone number provisioning, announcements, calling features
                  and capabilities (including call processing), MULTISERV, or
                  MULTISERV-like services, Automatic Call Distributor (ACD),
                  Carrier pre-subscription (e.g., long distance carrier,
                  intraLATA toll), Carrier Identification Code (CIC) portability
                  capabilities, testing and other operational features inherent
                  to the switch and switch software. It also provides access to
                  transport, signaling (ISDN User Part (ISUP) and Transaction
                  Capabilities Application Part (TCAP), and platforms such as
                  adjuncts, Public Safety Systems (911), operator services,
                  directory services and Advanced Intelligent Network (AIN).
                  Remote Switching Module functionality is included in the Local
                  Switching function. Local Switching shall also be capable of
                  routing local, intraLATA, interLATA, calls to international
                  subscriber's preferred carrier, call features (e.g., call
                  forwarding) and MULTISERV capabilities.

                  7.1.2    Local Switching, including the ability to route to
                  MCIm's transport facilities, dedicated facilities and systems,
                  shall be unbundled from all other unbundled Network Elements,
                  i.e., Operator Systems, Common Transport, and Dedicated
                  Transport. BellSouth shall provide MCIm with selective routing
                  via Line Class Codes. Further, MCIm and BellSouth shall
                  continue to work with the appropriate industry groups to
                  develop a long term solution for selective routing.

         7.2. TECHNICAL REQUIREMENTS

                                                             Attachment III - 18
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  7.2.1    Local Switching shall be equal to or better than the
                  requirements for Local Switching set forth in Bellcore's Local
                  Switching Systems General Requirements (FR-NWT-000064).

                           7.2.1.1  BellSouth shall route calls to the
                           appropriate trunk or lines for call origination or
                           termination.

                           7.2.1.2  Subject to section 7.1.2, above, BellSouth
                           shall route calls on a per line or per screening
                           class basis to (1) BellSouth platforms providing
                           Network Elements or additional requirements, (2) MCIm
                           designated platforms, or (3) third party platforms.

                           7.2.1.3  Subject to section 7.1.2, above, BellSouth
                           shall provide recorded announcements as designated by
                           MCIm and call progress tones to alert callers of call
                           progress and disposition. If BellSouth cannot provide
                           branded messages upon MCIm's request, BellSouth
                           shall revert to generic branding for all local
                           exchange service providers, including itself.

                           7.2.1.4  BellSouth shall change a subscriber from
                           BellSouth's services to MCIm's services without loss
                           of feature functionality, unless expressly agreed
                           otherwise by MCIm.

                           7.2.1.5  BellSouth shall perform routine testing
                           (e.g., Mechanized Loop Tests (MLT) and test calls
                           such as 105, 107 and 108 type calls) and fault
                           isolation on a schedule designated by MCIm.

                           7.2.1.6  BellSouth shall repair and restore any
                           equipment or any other maintainable component that
                           may adversely impact MCIm's use of unbundled Local
                           Switching.

                           7.2.1.7  BellSouth shall control congestion points
                           such as mass calling events, and network routing
                           abnormalities, using capabilities such as Automatic
                           Call Gapping, Automatic Congestion Control (e.g.
                           choke trunk groups), and Network Routing Overflow.
                           Application of such control shall be competitively
                           neutral and not favor any user of unbundled switching
                           or BellSouth.

                           7.2.1.8  BellSouth shall perform manual call trace as
                           designated by MCIm and permit subscriber originated
                           call trace.

                                                             Attachment III - 19
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           7.2.1.9  BellSouth shall record all billable events,
                           involving usage of the element, and send the
                           appropriate recording data to MCIm as outlined in
                           Attachment VIII.

                           7.2.1.10 For Local Switching used as 911 Tandems,
                           BellSouth shall allow interconnection from MCIm local
                           switching elements and BellSouth shall route the
                           calls to the appropriate Public Safety Access Point
                           (PSAP).

                           7.2.1.11 Where BellSouth provides the following
                           special services, it shall provide to MCIm:

                                    7.2.1.11.1 Essential Service Lines;

                                    7.2.1.11.2 Telephone Service Prioritization;

                                    7.2.1.11.3 Related services for handicapped;

                                    7.2.1.11.4 Soft dial tone where required by
                                    law. Where BellSouth provides soft dial
                                    tone, it shall do so on a
                                    competitively-neutral basis.

                                    7.2.1.11.5 Any other service required by law
                                    or regulation.

                           7.2.1.12 BellSouth shall provide Switching Service
                           Point (SSP) capabilities and signaling software to
                           interconnect the signaling links destined to the
                           Signaling Transfer Point Switch (STPs). In the event
                           that Local Switching is provided out of a switch
                           without SS7 capability, the Tandem shall provide this
                           capability as discussed in the section on Tandem
                           Switching. These capabilities shall adhere to
                           Bellcore specifications TCAP (GR-1432- CORE), ISUP
                           (GR-905-CORE), Call Management (GR-1429- CORE),
                           Switched Fractional DS1 (GR-1357-CORE), Toll Free
                           Service (GR-1428-CORE), Calling Name (GR-1597-CORE),
                           Line Information Database (GR-954-CORE), and Advanced
                           Intelligent Network (GR-2863-CORE).

                           7.2.1.13 BellSouth shall provide interfaces to
                           adjuncts through industry standard and Bellcore
                           interfaces. These adjuncts can include, but are not
                           limited to, Service Node, Service Circuit Node, Voice
                           Mail and Automatic Call Distributors. Examples of
                           existing interfaces are ANSI ISDN standards Q.931 and
                           Q.932.

                           7.2.1.14 BellSouth shall provide performance data
                           regarding a

                                                             Attachment III - 20
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           subscriber line, traffic characteristics or other
                           measurable elements to MCIm, upon MCIm's request.

                           7.2.1.15 BellSouth shall offer all Local Switching
                           features that are Technically Feasible and provide
                           feature offerings at parity to those provided by
                           BellSouth to itself or any other party. Such feature
                           offerings shall include but are not limited to:

                                    7.2.1.15.1 Basic and primary rate ISDN;

                                    7.2.1.15.2 Residential features;

                                    7.2.1.15.3 Custom Local Area Signaling
                                    Services (CLASS/LASS);

                                    7.2.1.15.4 Custom Calling Features;

                                    7.2.1.15.5 MULTISERV (including equivalent
                                    administrative capabilities, such as
                                    subscriber accessible reconfiguration and
                                    detailed message recording); and

                                    7.2.1.15.6 Advanced intelligent network
                                    triggers supporting MCIm, and BellSouth
                                    service applications, in BellSouth's SCPs.
                                    BellSouth shall offer to MCIm all AIN
                                    triggers currently available to BellSouth
                                    for offering AIN-based services in
                                    accordance with applicable Bellcore
                                    technical references:

                                         7.2.1.15.6.1 Off-Hook Immediate;

                                         7.2.1.15.6.2 Off-Hook Delay;

                                         7.2.1.15.6.3 Termination Attempt;

                                         7.2.1.15.6.4 3/6/10;

                                         7.2.1.15.6.5 Feature Code Dialing;

                                         7.2.1.15.6.6 Custom Dialing Plan(s)
                                         including 555 services; and

                                         7.2.1.15.7 When the following triggers
                                         are supported by BellSouth, BellSouth
                                         shall make said triggers available to
                                         MCIm:

                                                             Attachment III - 21
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         7.2.1.15.7.1 Private EAMF Trunk;

                                         7.2.1.15.7.2 Shared Interoffice Trunk
                                         (EAMF, SS7);

                                         7.2.1.15.7.3 N11;

                                         7.2.1.15.7.4 Automatic Route Selection.

                           7.2.1.16 Subject to section 7.1.2, above, BellSouth
                           shall assign each MCIm subscriber line the class of
                           service designated by MCIm using line class codes,
                           and shall route directory assistance calls from MCIm
                           subscribers as directed by MCIm at MCIm's option.
                           This includes each of the following call types:

                                    7.2.1.16.1 O+/O- calls

                                    7.2.1.16.2 911 calls

                                    7.2.1.16.3 411/DA calls

                                    7.2.1.16.4 InterLATA calls specific to PIC
                                    or regardless of PIC

                                    7.2.1.16.5 IntraLATA calls specific to PIC
                                    or regardless of PIC

                                    7.2.1.16.6 800/888 calls, prior to database
                                    query

                                    7.1.2.16.7 Call forwarding of any type
                                    supported on the switch, to a line or a
                                    trunk

                                    7.1.2.16.8 Any other customized routing that
                                    may be supported by the BellSouth switch

                           7.2.1.17 Subject to section 7.1.2, above, BellSouth
                           shall assign each MCIm subscriber line the class of
                           services designated by MCIm using line class codes
                           and shall route operator calls from MCIm subscribers
                           as directed by MCIm at MCIm's option. For example,
                           BellSouth may translate 0- and 0+ intraLATA traffic,
                           and route the call through appropriate trunks to an
                           MCIm Operator Services Position System (OSPS). Calls
                           from Local Switching must pass the ANI-II digits
                           unchanged.

                                                             Attachment III - 22
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           7.2.1.18 If an MCIm subscriber subscribes to MCIm
                           provided voice mail and messaging services, BellSouth
                           shall redirect incoming calls to the MCIm system
                           based upon presubscribed service arrangements (e.g.,
                           busy, don't answer, number of rings). In addition,
                           BellSouth shall provide a Standard Message Desk
                           Interface-Enhanced (SMDI-E) interface to the MCIm
                           system. BellSouth shall support the Inter-switch
                           Voice Messaging Service (IVMS) capability.

                           7.2.1.19 Local Switching shall be offered in
                           accordance with the requirements of the following
                           technical references and their future releases:

                                    7.2.1.19.1 GR-1298-CORE, AIN Switching
                                    System Generic Requirements;

                                    7.2.1.19.2 GR-1299-CORE, AIN Switch-Service
                                    Control Point (SCP)/Adjunct Interface
                                    Generic Requirements;

                                    7.2.1.19.3 TR-NWT-001284, AIN 0.1 Switching
                                    System Generic Requirements;

                                    7.2.1.19.4 SR-NWT-002247, AIN Release 1
                                    Update.

                  7.2.2    INTERFACE REQUIREMENTS

                           7.2.2.1  BellSouth shall provide the following
                           interfaces to loops:

                                    7.2.2.1.1  Standard Tip/Ring interface
                                    including loopstart or groundstart, on-hook
                                    signaling (e.g., for calling number, calling
                                    name and message waiting lamp);

                                    7.2.2.1.2  Coin phone signaling;

                                    7.2.2.1.3  Basic Rate Interface ISDN
                                    adhering to ANSI standards Q.931, Q.932 and
                                    appropriate Bellcore Technical Requirements;

                                    7.2.2.1.4  Two-wire analog interface to PBX
                                    to include reverse battery, E&M, wink start
                                    and DID;

                                    7.2.2.1.5  Four-wire analog interface to PBX
                                    to include reverse battery, E&M, wink start
                                    and DID;

                                                             Attachment III - 23
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    7.2.2.1.6  Four-wire DS1 interface to PBX or
                                    subscriber provided equipment
                                    (e.g.,computers and voice response systems);

                                    7.2.2.1.7  Primary Rate ISDN to PBX adhering
                                    to ANSI standards Q.931, Q.932 and
                                    appropriate Bellcore Technical Requirements;

                                    7.2.2.1.8  Switched Fractional DS1 with
                                    capabilities to configure Nx64 channels
                                    (where N ` 1 to 24); and

                                    7.2.2.1.9  Loops adhering to Bellcore
                                    TR-NWT-08 and TR-NWT-303 specifications to
                                    interconnect Digital Loop Carriers.

                           7.2.2.2  BellSouth shall provide access to the
                           following but not limited to:

                                    7.2.2.2.1  SS7 Signaling Network or
                                    Multi-Frequency trunking if requested by
                                    MCIm;

                                    7.2.2.2.2  Subject to section 7.1.2, above,
                                    interface to MCIm operator services systems
                                    or Operator Services through appropriate
                                    trunk interconnections for the system; and

                                    7.2.2.2.3  Subject to section 7.1.2, above,
                                    interface to MCIm directory assistance
                                    services through the MCIm switched network
                                    or to Directory Services through the
                                    appropriate trunk interconnections for the
                                    system; and 950 access or other MCIm
                                    required access to interexchange carriers as
                                    requested through appropriate trunk
                                    interfaces.

         7.3  INTEGRATED SERVICES DIGITAL NETWORK (ISDN)

                  7.3.1    Integrated Services Digital Network (ISDN) is defined
                  in two variations. The first variation is Basic Rate ISDN
                  (BRI). BRI consists of 2 Bearer (B) Channels and one Data (D)
                  Channel. The second variation is Primary Rate ISDN (PRI). PRI
                  consists of 23 B Channels and one D Channel. Both BRI and PRI
                  B Channels may be used for voice, Circuit Switched Data (CSD)
                  or Packet Switched Data (PSD). The BRI D Channel may be used
                  for call related signaling, non-call related signaling or
                  packet switched data. The PRI D Channel may be

                                                              Attachment III -24
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  used for call related signaling.

                  7.3.2    TECHNICAL REQUIREMENTS ISDN

                           7.3.2.1  BellSouth shall offer Data Switching
                           providing ISDN that, at a minimum:

                           7.3.2.2  Provide integrated Packet handling
                           capabilities;

                           7.3.2.3  Allow for full 2B+D Channel functionality
                           for BRI; and

                           7.3.2.4  Allow for full 23B+D Channel functionality
                           for PRI.

                           7.3.2.5  Each B Channel shall allow for voice, 64
                           Kbps CSD, and PSD of 128 logical channels at minimum
                           speeds of 19 Kbps throughput of each logical channel
                           up to the total capacity of the B Channel.

                           7.3.2.6  Each B Channel shall provide capabilities
                           for alternate voice and data on a per call basis.

                           7.3.2.7  The BRI D Channel shall allow for call
                           associated signaling, non-call associated signaling
                           and PSD of 16 logical channels at minimum speeds of
                           9.6 Kbps throughput of each logical channel up to the
                           total capacity of the D channel.

                           7.3.2.8  The PRI D Channel shall allow for call
                           associated signaling.

                  7.3.3    INTERFACE REQUIREMENTS ISDN

                           7.3.3.1  BellSouth shall provide the BRI U interface
                           using 2-wire copper loops in accordance with
                           TR-NWT-000393, January 1991, Generic Requirements for
                           ISDN Basic Access Digital Subscriber Lines.

                           7.3.3.2  BellSouth shall provide the BRI interface
                           using Digital Subscriber Loops adhering to Bellcore
                           TR-NWT-303 specifications to interconnect Digital
                           Loop Carriers.

                           7.3.3.3 BellSouth shall offer PSD interfaces adhering
                           to the X.25, X.75 and X.75' ANSI and Bellcore
                           requirements.

                           7.3.3.4 BellSouth shall offer PSD trunk interfaces
                           operating at 56 Kbps.

                                                             Attachment III - 25
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

SECTION 8.  OPERATOR SYSTEMS

See Attachment VIII, Section 6.1.2 Directory Assistance Service and 6.1.3
Operator Service.

SECTION 9.  COMMON TRANSPORT

         9.1  DEFINITION

         Common Transport is an interoffice transmission path between BellSouth
         Network Elements (illustrated in Figure 2) shared by carriers. Where
         BellSouth Network Elements are connected by intra-office wiring, such
         wiring is provided as a part of the Network Elements and is not Common
         Transport. BellSouth shall offer Common Transport as of the effective
         date of the agreement, at DS0, DS1, DS3, STS-1 or higher transmission
         bit rate circuits. Common Transport consists of BellSouth inter-office
         transport facilities and is distinct and separate from local switching.

FIGURE 2              [GRAPHIC OMITTED}

         9.2  TECHNICAL REQUIREMENTS

                  9.2.1    BellSouth shall be responsible for the engineering,
                  provisioning, and maintenance of the underlying equipment and
                  facilities that are used to provide Common Transport.

                  9.2.2    At a minimum, Common Transport shall meet all of the
                  requirements set forth in the following technical references
                  (as applicable for the transport technology being used):

                  9.2.3.    ANSI T1.101-1994, American National Standard for
                  Telecommunications - Synchronization Interface Standard
                  Performance and Availability;

                           9.2.3.1  ANSI T1.102-1993, American National Standard
                           for Telecommunications - Digital Hierarchy -
                           Electrical Interfaces;

                           9.2.3.2  ANSI T1.102.01-199x, American National
                           Standard for Telecommunications - Digital Hierarchy -
                           VT1.5;

                                                             Attachment III - 26
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           9.2.3.3  ANSI T1.105-1995, American National Standard
                           for Telecommunications - Synchronous Optical Network
                           (SONET) - Basic Description including Multiplex
                           Structure, Rates and Formats;

                           9.2.3.4  ANSI T1.105.01-1995, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) Automatic Protection Switching;

                           9.2.3.5  ANSI T1.105.02-1995, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) - Payload Mappings;

                           9.2.3.6  ANSI T1.105.03-1994, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) - Jitter at Network Interfaces;

                           9.2.3.7  ANSI T1.105.03a-1995, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) - Jitter at Network Interfaces - DS1
                           Supplement;

                           9.2.3.8  ANSI T1.105.05-1994, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) - Tandem Connection;

                           9.2.3.9  ANSI T1.105.06-199x, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) - Physical Layer Specifications;

                           9.2.3.10 ANSI T1.105.07-199x, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) - Sub STS-1 Interface Rates and
                           Formats;

                           9.2.3.11 ANSI T1.105.09-199x, American National
                           Standard for Telecommunications - Synchronous Optical
                           Network (SONET) - Network Element Timing and
                           Synchronization;

                           9.2.3.12 ANSI T1.106-1988, American National Standard
                           for Telecommunications - Digital Hierarchy - Optical
                           Interface Specifications (Single Mode);

                           9.2.3.13 ANSI T1.107-1988, American National Standard
                           for Telecommunications - Digital Hierarchy - Formats
                           Specifications;

                                                             Attachment III - 27
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           9.2.3.14 ANSI T1.107a-1990-American National Standard
                           for Telecommunications - Digital Hierarchy -
                           Supplement Formats Specifications; (DS3 Format
                           Applications);

                           9.2.3.15 ANSI T1.107b-1991 -American National
                           Standard for Telecommunications - Digital Hierarchy -
                           Supplement to Formats Specifications;

                           9.2.3.16 ANSI T1.117-1991, American National Standard
                           for Telecommunications - Digital Hierarchy - Optical
                           Interface Specifications (SONET) (Single Mode - Short
                           Reach);

                           9.2.3.17 ANSI T1.403-1989, Carrier to Subscriber
                           Installation, DS1 Metallic Interface Specification;

                           9.2.3.18 ANSI T1.404-1994, Network-to-Subscriber
                           Installation - DS3 Metallic Interface Specification;

                           9.2.3.19 ITU Recommendation G.707, Network node
                           interface for the synchronous digital hierarchy
                           (SDH);

                           9.2.3.20 ITU Recommendation G.704, Synchronous frame
                           structures used at 1544, 6312, 2048, 8488 and 44736
                           kbit/s hierarchical levels;

                           9.2.3.21 Bellcore FR-440 and TR-NWT-000499, Transport
                           Systems Generic Requirements (TSGR): Common
                           Requirements;

                           9.2.3.22 Bellcore GR-820-CORE, Generic Transmission
                           Surveillance: DS1 & DS3 Performance;

                           9.2.3.23 Bellcore GR-253-CORE, Synchronous Optical
                           Network Systems (SONET); Common Generic Criteria;

                           9.2.3.24 Bellcore TR-NWT 000507, Transmission,
                           Section 7, Issue 5 (Bellcore, December 1993). (A
                           module of LSSGR, FR-NWT- 000064.);

                           9.2.3.25 Bellcore TR-NWT-000776, Network Interface
                           Description for ISDN Subscriber Access;

                           9.2.3.26 Bellcore TR-INS-000342, High-Capacity
                           Digital Special Access Service-Transmission Parameter
                           Limits and Interface Combinations, Issue 1 February
                           1991;

                                                             Attachment III - 28
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           9.2.3.27 Bellcore ST-TEC-000052, Telecommunications
                           Transmission Engineering Textbook, Volume 2:
                           Facilities, Third Edition, Issue I May 1989;

                           9.2.3.28 Bellcore ST-TEC-000051, Telecommunications
                           Transmission Engineering Textbook Volume 1:
                           Principles, Third Edition. Issue 1 August 1987;

SECTION 10. DEDICATED TRANSPORT

         10.1 DEFINITION

                  10.1.1   Dedicated Transport is an interoffice transmission
                  path between MCIm designated locations to which MCIm is
                  granted exclusive use. Such locations may include BellSouth
                  central offices or other locations, MCIm network components,
                  other carrier network components, or subscriber premises.
                  Dedicated Transport is depicted below in Figure 3.

                               [GRAPHIC OMITTED]

                                    FIGURE 3

                  10.1.2   BellSouth shall offer Dedicated Transport in each of
                  the following manners:

                           10.1.2.1 As capacity on a shared facility.

                           10.1.2.2 As a circuit (e.g., DS1, DS3, STS-1)
                           dedicated to MCIm.

                           10.1.2.3 As a system (i.e., the equipment and
                           facilities used to provide Dedicated Transport such
                           as SONET ring) dedicated to MCIm.

                  10.1.3   When Dedicated Transport is provided as a circuit or
                  as capacity on a shared facility, it shall include (as
                  appropriate):

                           10.1.3.1 Multiplexing functionality;

                                                             Attachment III - 29
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           10.1.3.2 Grooming functionality; and,

                           10.1.3.3 Redundant equipment and facilities necessary
                           to support protection and restoration.

                  10.1.4   When Dedicated Transport is provided as a system it
                  shall include:

                           10.1.4.1 Transmission equipment such as multiplexers,
                           line terminating equipment, amplifiers, and
                           regenerators;

                           10.1.4.2 Inter-office transmission facilities such as
                           optical fiber, lit fiber, copper twisted pair, and
                           coaxial cable;

                           10.1.4.3 Redundant equipment and facilities necessary
                           to support protection and restoration; and,

                           10.1.4.4 Dedicated Transport includes the Digital
                           Cross-Connect System (DCS) functionality as an
                           option. DCS is described below in Section 10.5.

         10.2 TECHNICAL REQUIREMENTS -

         This Section sets forth technical requirements for all Dedicated
         Transport.

                  10.2.1   When BellSouth provides Dedicated Transport as a
                  circuit or a system, the entire designated transmission
                  circuit or system (e.g., DS1, DS3, STS-1) shall be dedicated
                  to MCIm designated traffic.

                  10.2.2   BellSouth shall offer Dedicated Transport using
                  currently available technologies including, but not limited
                  to, DS1 and DS3 transport systems, SONET (or SDH)
                  Bi-directional Line Switched Rings, SONET (or SDH)
                  Unidirectional Path Switched Rings, and SONET (or SDH)
                  point-to-point transport systems (including linear add-drop
                  systems), at all available transmission bit rates.

                  10.2.3   When requested by MCIm, Dedicated Transport shall
                  provide physical diversity. Physical diversity means that two
                  circuits are provisioned in such a way that no single failure
                  of facilities or equipment will cause a failure on both
                  circuits.

                  10.2.4   When physical diversity is requested by MCIm,
                  BellSouth shall provide the maximum feasible physical
                  separation between transmission paths for all facilities and
                  equipment (unless otherwise

                                                             Attachment III - 30
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  agreed by MCIm).

                  10.2.5   Upon MCIm's request, BellSouth shall provide real
                  time and continuous remote access to performance monitoring
                  and alarm data affecting, or potentially affecting, MCIm's
                  traffic.

                  10.2.6   BellSouth shall offer the following interface
                  transmission rates for Dedicated Transport:

                           10.2.6.1 DS1 (Extended SuperFrame - ESF/B8ZS, D4, and
                           unframed applications shall be provided);

                           10.2.6.2 DS3 (C-bit Parity, M13, and unframed
                           applications shall be provided);

                           10.2.6.3 SONET standard interface rates in accordance
                           with ANSI T1.105 and ANSI T1.105.07 and physical
                           interfaces per ANSI T1.106.06 (including referenced
                           interfaces). In particular, VT1.5 based STS-1s will
                           be the interface at an MCIm service node.

                           10.2.6.4 SDH Standard interface rates in accordance
                           with International Telecommunications Union (ITU)
                           Recommendation G.707 and Plesiochronous Digital
                           Hierarchy (PDH) rates per ITU Recommendation G.704.

                  10.2.7   BellSouth shall provide cross-office wiring up to a
                  suitable Point of Termination (POT) between Dedicated
                  Transport and MCIm designated equipment. BellSouth shall
                  provide the following equipment for the physical POT:

                           10.2.7.1 DSX1 for DS1s or VT1.5s;

                           10.2.7.2 DSX3 for DS3s or STS-1s; and

                           10.2.7.3 LGX for optical signals (e.g., OC-3 and
                           OC-12).

                  10.2.8   Left Blank Intentionally

                  10.2.9   For Dedicated Transport provided as a system,
                  BellSouth shall design the system (including but not limited
                  to facility routing and termination points) according to MCIm
                  specifications where the MCIm specifications are available.
                  Those MCIm specifications not available shall be addressed via
                  the bona fide request process.

                                                             Attachment III - 31
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    10.2.10    Upon MCIm's request, BellSouth
                                    shall provide MCIm with electronic
                                    provisioning control of an MCIm specified
                                    Dedicated Transport on SONET rings. As
                                    system development allows, either initiated
                                    by BellSouth or via the bona fide request
                                    process, BellSouth shall provide electronic
                                    provisioning control of linear transport
                                    systems.

                                    10.2.11    BellSouth shall offer Dedicated
                                    Transport together with and separately from
                                    DCS.

         10.3 TECHNICAL REQUIREMENTS FOR DEDICATED TRANSPORT USING SONET
         TECHNOLOGY

         This Section sets forth additional technical requirements for Dedicated
         Transport using SONET technology including rings, point-to-point
         systems, and linear add-drop systems.

                  10.3.1   All SONET Dedicated Transport provided as a system
                  shall:

                           10.3.1.1 Be synchronized from both a primary and
                           secondary Stratum 1 level timing source.

                           10.3.1.2 Provide SONET standard interfaces which
                           properly interwork with SONET standard equipment from
                           other vendors. This includes, but is not limited to,
                           SONET standard Section, Line and Path performance
                           monitoring, maintenance signals, alarms, and data
                           channels.

                           10.3.1.3 Provide Data Communications Channel (DCC) or
                           equivalent connectivity through the SONET transport
                           system. Dedicated Transport provided over a SONET
                           transport system shall be capable of routing DCC
                           messages between MCIm and SONET network components
                           connected to the Dedicated Transport. For example, if
                           MCIm leases a SONET ring from BellSouth, that ring
                           shall support DCC message routing between MCIm and
                           SONET network components connected to the ring.

                           10.3.1.4 Support the following performance
                           requirements for each circuit (STS-1, DS1, DS3,
                           etc.):

                                    10.3.1.4.1 No more than 10 Errored Seconds
                                    Per Day (Errored Seconds are defined in the
                                    technical reference at Section 10.4.5); and

                                                             Attachment III - 32
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    10.3.1.4.2 No more than 1 Severely Errored
                                    Second Per Day (Severely Errored Seconds are
                                    defined in the technical reference at
                                    Section 10.4.5).

                  10.3.2   SONET rings shall:

                           10.3.2.1 Be provisioned on physically diverse fiber
                           optic cables (including separate building entrances
                           where available and diversely routed intraoffice
                           wiring). "Diversely routed" shall be interpreted as
                           the maximum feasible physical separation between
                           transmission paths, unless otherwise agreed by MCIm.

                           10.3.2.2 Support dual ring interworking per SONET
                           Standards.

                           10.3.2.3 Where Technically Feasible, provide the
                           necessary redundancy in optics, electronics, and
                           transmission paths (including intra-office wiring)
                           such that no single failure will cause a service
                           interruption.

                           10.3.2.4 Provide the ability to disable ring
                           protection switching at MCIm's direction (selective
                           protection lock-out). This requirement applies to
                           line switched rings only. The only exceptions to this
                           requirement shall be BellSouth SONET equipment in use
                           as of the Effective Date which lacks that
                           functionality.

                           10.3.2.5 Provide the ability to use the protection
                           channels to carry traffic (extra traffic). This
                           requirement applies to line switched rings only. The
                           only exceptions to this requirement shall be
                           BellSouth SONET equipment in use as of the Effective
                           Date which lacks that functionality.

                           10.3.2.6 Provide 50 millisecond restoration unless a
                           ring protection delay is set to accommodate dual ring
                           interworking schemes.

                           10.3.2.7 Have settable ring protection switching
                           thresholds that shall be set in accordance with
                           MCIm's specifications.

                           10.3.2.8 Provide revertive protection switching with
                           a settable wait to restore delay with a default
                           setting of 5 minutes. This requirement applies to
                           line switched rings only.

                           10.3.2.9 Provide non-revertive protection switching.
                           This requirement applies to path switched rings only.

                                                            Attachment III - 33
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           10.3.2.10 Adhere to the following availability
                           requirements, where availability is defined in the
                           technical reference set forth in Section 10.4.5.

                                   10.3.2.10.1 No more than 0.25 minutes of
                                   unavailability month; and

                                   10.3.2.10.2 No more than 0.5 minutes of
                                   unavailability per year.

         10.4 At a minimum, Dedicated Transport shall meet each of the
         requirements set forth in Section 9.2.3 and in the following technical
         references.

                  10.4.1   ANSI T1.105.04-1995, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET) -
                  Data Communication Channel Protocols and Architectures;

                  10.4.2   ANSI T1.119-1994, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET) -
                  Operations, Administration, Maintenance, and Provisioning
                  (OAM&P) Communications;

                  10.4.3   ANSI T1.119.01-1995, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET)
                  Operations, Administration, Maintenance, and Provisioning
                  (OAM&P) Communications Protection Switching Fragment;

                  10.4.4   ANSI T1.119.02-199x, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET)
                  Operations, Administration, Maintenance, and Provisioning
                  (OAM&P) Communications Performance Monitoring Fragment;

                  10.4.5   ANSI T1.231-1993 -American National Standard for
                  Telecommunications - Digital Hierarchy - Layer 1 In-Service
                  Digital Transmission Performance Monitoring.

         10.5 DIGITAL CROSS-CONNECT SYSTEM (DCS)

                  10.5.1   DEFINITION:

                           10.5.1.1 DCS provides automated cross connection of
                           Digital Signal level 0 (DS0) or higher transmission
                           bit rate digital channels within physical interface
                           facilities. Types of DCSs

                                                                 Attachment - 34
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           include but are not limited to DCS 1/0s, DCS 3/1s,
                           and DCS 3/3s, where the nomenclature 1/0 denotes
                           interfaces typically at the DS1 rate or greater with
                           cross- connection typically at the DS0 rate. This
                           same nomenclature, at the appropriate rate
                           substitution, extends to the other types of DCSs
                           specifically cited as 3/1 and 3/3. Types of DCSs that
                           cross-connect Synchronous Transport Signal level 1
                           (STS-1 s) or other Synchronous Optical Network
                           (SONET) signals (e.g., STS-3) are also DCSs, although
                           not denoted by this same type of nomenclature. DCS
                           may provide the functionality of more than one of the
                           aforementioned DCS types (e.g., DCS 3/3/1 which
                           combines functionality of DCS 3/3 and DCS 3/1). For
                           such DCSs, the requirements will be, at least, the
                           aggregation of requirements on the "component" DCSs.

                           10.5.1.2 In locations where automated cross
                           connection capability does not exist, DCS will be
                           defined as the combination of the functionality
                           provided by a Digital Signal Cross-Connect (DSX) or
                           Light Guide Cross-Connect (LGX) patch panels and D4
                           channel banks or other DS0 and above multiplexing
                           equipment used to provide the function of a manual
                           cross connection.

                           10.5.1.3 Interconnection between a DSX or LGX, to a
                           switch, another cross-connect, or other service
                           platform device, is included as part of DCS.

         10.6 DCS TECHNICAL REQUIREMENTS

                  10.6.1   DCS shall provide completed end-to-end cross
                  connection of the channels designated by MCIm.

                  10.6.2   Where Technically Feasible, DCS shall perform
                  facility grooming, multipoint bridging, one-way broadcast,
                  two-way broadcast, and facility test functions.

                  10.6.3   DCS shall provide multiplexing, format conversion,
                  signaling conversion, or other functions.

                  10.6.4   The end-to-end cross connection assignment shall be
                  input to the underlying device used to provide DCS from an
                  operator at a terminal or via an intermediate system. The
                  cross connection assignment shall remain in effect whether or
                  not the circuit is in use.

                  10.6.5   BellSouth shall continue to administer and maintain
                  DCS,

                                                             Attachment III - 35
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  including updates to the control software to current available
                  releases.

                  10.6.6   BellSouth shall provide various types of Digital
                  Cross-Connect Systems including:

                           10.6.6.1 DS0 cross-connects (typically termed DCS
                           1/0);

                           10.6.6.2 DS1/VT1.5 (Virtual Tributaries at the
                           1.5Mbps rate) cross-connects (typically termed DCS
                           3/1);

                           10.6.6.3 DS3 cross-connects (typically termed DCS
                           3/3);

                           10.6.6.4 STS-1 cross-connects; and

                           10.6.6.5 Other Technically Feasible cross-connects
                           designated by MCIm.

                  10.6.7   BellSouth shall provide an automated interface which
                  allows real time configuration and reconfiguration of the
                  channels between the physical interfaces.

                  10.6.8   Left Blank Intentionally

                  10.6.9   DCS shall continuously monitor protected circuit
                  packs and redundant common equipment.

                  10.6.10  DCS shall automatically switch to a protection
                  circuit pack on detection of a failure or degradation of
                  normal operation.

                  10.6.11  The underlying equipment used to provide DCS shall be
                  equipped with a redundant power supply or a battery back-up.

                  10.6.12  BellSouth shall make available to MCIm spare
                  facilities and equipment necessary for provisioning repairs,
                  and to meet MCIm's maintenance standards as specified in the
                  Provisioning and Maintenance sections.

                  10.6.13  At MCIm's option, BellSouth shall provide MCIm with
                  real time performance monitoring and alarm data on the signals
                  and the components of the underlying equipment used to provide
                  DCS that actually impact MCIm's services.

                  10.6.14  Where Technically Feasible, at MCIm's option,
                  BellSouth shall provide MCIm with real time ability to
                  initiate tests on integrated equipment used to test the
                  signals and the underlying equipment used

                                                             Attachment III - 36
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  to provide DCS, as well as other integrated functionality for
                  routine testing and fault isolation.

                  10.6.15  Where Technically Feasible, DCS shall provide SONET
                  to asynchronous gateway functionality (e.g., STS-1 to DS1 or
                  STS-1 to DS3).

                  10.6.16  Where Technically Feasible, DCS shall perform optical
                  to electrical conversion where the underlying equipment used
                  to provide DCS contains optical interfaces or terminations
                  (e.g., Optical Carrier level 3, i.e., OC-3, interfaces on a
                  DCS 3/1).

                  10.6.17  Where Technically Feasible, DCS shall have SONET ring
                  terminal functionality where the underlying equipment used to
                  provide DCS acts as a terminal on a SONET ring.

                  10.6.18  Where Technically Feasible, DCS shall provide
                  multipoint bridging of multiple channels to other DCSs. MCIm
                  may designate multipoint bridging to be one-way broadcast from
                  a single master to multiple tributaries, or two-way broadcast
                  between a single master and multiple tributaries.

                  10.6.19  Where Technically Feasible, DCS shall multiplex lower
                  speed channels onto a higher speed interface and demultiplex
                  higher speed channels onto lower speed interfaces as
                  designated by MCIm.

         10.7 DCS INTERFACE REQUIREMENTS

                  10.7.1   BellSouth shall provide physical interfaces on DS0,
                  DS1, and VT1.5 channel cross-connect devices at the DS1 rate
                  or higher. In all such cases, these interfaces shall be in
                  compliance with applicable Bellcore, ANSI, ITU, and MCIm
                  standards.

                  10.7.2   BellSouth shall provide physical interfaces on DS3
                  channel cross-connect devices at the DS3 rate or higher. In
                  all such cases, these interfaces shall be in compliance with
                  applicable Bellcore, ANSI, ITU, and MCIm standards.

                  10.7.3   BellSouth shall provide physical interfaces on STS-1
                  cross-connect devices at the OC-3 rate or higher. In all such
                  cases, these interfaces shall be in compliance with applicable
                  Bellcore, ANSI, ITU, and MCIm standards.

                  10.7.4   Interfaces on all other cross-connect devices shall
                  be in compliance with applicable Bellcore, ANSI, ITU, and MCIm
                  standards.

                                                             Attachment III - 37
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         10.8 DCS shall, at a minimum, meet all the requirements set forth in
         the following technical references:

                  10.8.1   ANSI T1.102-1993, American National Standard for
                  Telecommunications - Digital Hierarchy - Electrical
                  Interfaces;

                  10.8.2   ANSI T1.102.01-199x, American National Standard for
                  Telecommunications - Digital Hierarchy - VT1.5;

                  10.8.3   ANSI T1.105-1995, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET) -
                  Basic Description including Multiplex Structure, Rates and
                  Formats;

                  10.8.4   ANSI T1.105.03-1994, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET) -
                  Jitter at Network Interfaces;

                  10.8.5   ANSI T1.105.03a-1995, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET):
                  Jitter at Network Interfaces - DS1 Supplement;

                  10.8.6   ANSI T1.105.06-199x, American National Standard for
                  Telecommunications - Synchronous Optical Network (SONET) -
                  Physical Layer Specifications;

                  10.8.7   ANSI T1.106-1988, American National Standard for
                  Telecommunications - Digital Hierarchy - Optical Interface
                  Specifications (Single Mode);

                  10.8.8   ANSI T1.107-1988, American National Standard for
                  Telecommunications - Digital Hierarchy - Formats
                  Specifications;

                  10.8.9   ANSI T1.107a-1990, American National Standard for
                  Telecommunications - Digital Hierarchy - Supplement to Formats
                  Specifications (DS3 Format Applications);

                  10.8.10  ANSI T1.107b-1991, American National Standard for
                  Telecommunications - Digital Hierarchy - Supplement to Formats
                  Specifications;

                  10.8.11  ANSI T1.117-1991, American National Standard for
                  Telecommunications - Digital Hierarchy - Optical Interface
                  Specifications (SONET) (Single Mode - Short Reach);

                                                             Attachment III - 38
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  10.8.12  ANSI T1.403-1989, Carrier to Subscriber Installation,
                  DS1 Metallic Interface Specification:

                  10.8.13 ANSI T1.404-1994, Network-to-Subscriber Installation -
                  DS3 Metallic Interface Specification;

                  10.8.14  FR-440 and TR-NWT-000499, Transport Systems Generic
                  Requirements (TSGR): Common Requirements;

                  10.8.15  GR-820-CORE, Generic Transmission Surveillance: DS1 &
                  DS3 Performance;

                  10.8.16  GR-253-CORE, Synchronous Optical Network Systems
                  (SONET); Common Generic Criteria; and

                  10.8.17  TR-NWT-000776, Network Interface Description for ISDN
                  Subscriber Access.

SECTION 11. SIGNALING LINK TRANSPORT -

         11.1 DEFINITION

         Signaling Link Transport is a set of two or four dedicated 56 Kbps
         transmission paths between MCIm-designated Signaling Points of
         Interconnection (SPOI) that provides appropriate physical diversity and
         a cross connect at a BellSouth STP site.

         11.2 TECHNICAL REQUIREMENTS

                  11.2.1   Signaling Link Transport shall consist of full duplex
                  mode 56 Kbps transmission paths.

                  11.2.2   Of the various options available, Signaling Link
                  Transport shall perform in the following two ways:

                           11.2.2.1 As an "A-link" which is a connection between
                           a switch or SCP and a home Signaling Transfer Point
                           Switch (STPs) pair; and

                           11.2.2.2 As a "D-link" which is a connection between
                           two STPs pairs in different company networks (e.g.,
                           between two STPs pairs for two Competitive Local
                           Exchange Carriers (CLECs)).

                  11.2.3   Signaling Link Transport shall consist of two or more
                  signaling link layers as follows:

                                                             Attachment III - 39
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           11.2.3.1 An A-link layer shall consist of two links.

                           11.2.3.2 A D-link layer shall consist of four links.

                  11.2.4   A signaling link layer shall satisfy a performance
                  objective such that:

                           11.2.4.1 There shall be no more than two minutes down
                           time per year for an A-link layer, and 11.2.4.2 There
                           shall be negligible (less than 2 seconds) down time
                           per year for a D-link layer.

                  11.2.5   A signaling link layer shall satisfy interoffice and
                  intraoffice diversity of facilities and equipment, such that:
                  11.2.5.1 No single failure of facilities or equipment causes
                  the failure of both links in an A-link layer (i.e., the links
                  should be provided on a minimum of two separate physical paths
                  end-to-end); and 11.2.5.2 No two concurrent failures of
                  facilities or equipment shall cause the failure of all four
                  links in a D-link layer (i.e., the links should be provided on
                  a minimum of three separate physical paths end-to-end).

         11.3 INTERFACE REQUIREMENTS

                  11.3.1   There shall be a DS1 (1.544 Mbps) interface at the
                  MCIm-designated SPOIs. Each 56 Kbps transmission path shall
                  appear as a DS0 channel within the DS1 interface.

SECTION 12. SIGNALING TRANSFER POINTS (STPS)

         12.1 DEFINITION

         Signaling Transfer Points (STPs) provide functionality that enable the
         exchange of SS7 messages among and between switching elements, database
         elements and signaling transfer points. Figure 4 depicts Signaling
         Transfer Points.

                                                             Attachment III - 40
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                               [GRAPHIC OMITTED]

                                    FIGURE 4

         12.2 TECHNICAL REQUIREMENTS

                  12.2.1   STPs shall provide access to all other Network
                  Elements connected to the BellSouth SS7 network. These
                  include:

                           12.2.1.1 BellSouth Local Switching or Tandem
                           Switching;

                           12.2.1.2 BellSouth Service Control Points/DataBases;

                           12.2.1.3 Third-party local or tandem switching
                           systems; and

                           12.2.1.4 Third-party-provided STPs.

                  12.2.2   The connectivity provided by STPs shall fully support
                  the functions of all other Network Elements connected to
                  BellSouth's SS7 network. This explicitly includes the use of
                  BellSouth's SS7 network to convey messages which neither
                  originate nor terminate at a signaling end point directly
                  connected to the BellSouth SS7 network (i.e., transit
                  messages). When the BellSouth SS7 network is used to convey
                  transit messages, there shall be no alteration of the
                  Integrated Services Digital Network User Part (ISDNUP) or
                  Transaction Capabilities Application Part (TCAP) user data
                  that constitutes the content of the message.

                                                             Attachment III - 41
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  12.2.3   If a BellSouth tandem switch routes calling traffic,
                  based on dialed or translated digits, on SS7 trunks between an
                  MCIm local switch and third party local switch, BellSouth's
                  SS7 network shall convey the TCAP messages that are necessary
                  to provide Call Management features (Automatic Callback,
                  Automatic Recall, and Screening List Editing) between the MCIm
                  local STPs and the STPs that provide connectivity with the
                  third party local switch, even if the third party local switch
                  is not directly connected to BellSouth's STPs.

                  12.2.4   STPs shall provide all functions of the MTP as
                  specified in ANSI T1.111 (Reference 12.5.2). This includes:

                           12.2.4.1 Signaling Data Link functions, as specified
                           in ANSI T1.111.2;

                           12.2.4.2 Signaling Link functions, as specified in
                           ANSI T1.111.3; and

                           12.2.4.3 Signaling Network Management functions, as
                           specified in ANSI T1.111.4.

                  12.2.5   STPs shall provide all functions of the SCCP
                  necessary for Class 0 (basic connectionless) service, as
                  specified in ANSI T1.112 (Reference 12.5.4). In particular,
                  this includes Global Title Translation (GTT) and SCCP
                  Management procedures, as specified in T1.112.4.

                  12.2.6   In cases where the destination signaling point is a
                  BellSouth local or tandem switching system or data base, or is
                  an MCIm or third party local or tandem switching system
                  directly connected to BellSouth's SS7 network, BellSouth STPs
                  shall perform final GTT of messages to the destination and
                  SCCP Subsystem Management of the destination. In all other
                  cases, STPs shall perform intermediate GTT of messages to a
                  gateway pair of STPs in an SS7 network connected with the
                  BellSouth SS7 network, and shall not perform SCCP Subsystem
                  Management of the destination.

                  12.2.7   STPs shall also provide the capability to route SCCP
                  messages based on ISNI, as specified in ANSI T1.118 (Reference
                  12.5.7), when this capability becomes available on BellSouth
                  STPs.

                  12.2.8   STPs shall provide all functions of the OMAP commonly
                  provided by STPs, as specified in the reference in Section
                  12.5.6. Upon MCIm request, BellSouth will identify the
                  switches in which OMAP functionality is available. This
                  includes:

                           12.2.8.1 MTP Routing Verification Test (MRVT); and,

                                                             Attachment III - 42
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           12.2.8.2 SCCP Routing Verification Test (SRVT).

                  12.2.9   In cases where the destination signaling point is a
                  BellSouth local or tandem switching system or DB, or is an
                  MCIm or third party local or tandem switching system directly
                  connected to the BellSouth SS7 network, STPs shall perform
                  MRVT and SRVT to the destination signaling point. In all other
                  cases, STPs shall perform MRVT and SRVT to a gateway pair of
                  STPs in an SS7 network connected with the BellSouth SS7
                  network. This requirement shall be superseded by the
                  specifications for Internetwork MRVT and SRVT if and when
                  these become approved ANSI standards and available
                  capabilities of BellSouth STPs, and when mutually agreed upon
                  by MCIm and BellSouth.

                  12.2.10  STPs shall be equal to or better than the following
                  performance requirements:

                           12.2.10.1 MTP Performance, as specified in ANSI
                           T1.111.6; and

                           12.2.10.2 SCCP Performance, as specified in ANSI
                           T1.112.5.

         12.3 INTERFACE REQUIREMENTS

                  12.3.1   BellSouth shall provide the following STPs options to
                  connect MCIm or MCIm-designated local switching systems or
                  STPs to the BellSouth SS7 network:

                           12.3.1.1 An A-link interface from MCIm local
                           switching systems; and,

                  12.3.2   Each type of interface shall be provided by one or
                  more sets (layers) of signaling links, as follows:

                           12.3.2.1 An A-link layer shall consist of two links,
                           as depicted in Figure 6.

                                                             Attachment III - 43
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                               [GRAPHIC OMITTED]

                           FIGURE 6. A-LINK INTERFACE

                  12.3.3   The Signaling point of Interconnection (SPOI) for
                  each link shall be located at a cross-connect element, such as
                  a DSX-1, in the Central Office (CO) where the BellSouth STPs
                  is located. There shall be a DSl or higher rate transport
                  interface at each of the SPOIs. Each signaling link shall
                  appear as a DS0 channel within the DS1 or higher rate
                  interface. BellSouth shall offer higher rate DS1 signaling for
                  interconnecting MCIm local switching systems or STPs with
                  BellSouth STPs as soon as these become approved ANSI standards
                  and available capabilities of BellSouth STPs. MCIm and
                  BellSouth shall cooperate to establish mutually agreed upon
                  SPOIs.

                  12.3.4   BellSouth shall provide MTP and SCCP protocol
                  interfaces that shall conform to all sections relevant to the
                  MTP or SCCP in the following specifications:

                           12.3.4.1 Bellcore GR-905-CORE, Common Channel
                           Signaling Network Interface Specification (CCSNIS)
                           Supporting Network Interconnection, Message Transfer
                           Part (MTP), and Integrated Services Digital Network
                           User Part (ISDNUP); and

                           12.3.4.2 Bellcore GR-1432-CORE, CCS Network Interface
                           Specification (CCSNIS) Supporting Signaling
                           Connection Control Part (SCCP) and Transaction
                           Capabilities Application Part (TCAP).

         12.4 MESSAGE SCREENING

                  12.4.1   BellSouth shall set message screening parameters so
                  as to accept messages from MCIm local or tandem switching
                  systems destined to any signaling point in the BellSouth SS7
                  network with

                                                             Attachment III - 44
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  which the MCIm switching system has a legitimate signaling
                  relation.

                  12.4.2   BellSouth shall set message screening parameters so
                  as to accept messages from MCIm local or tandem switching
                  systems destined to any signaling point or network
                  interconnected to the BellSouth SS7 network with which the
                  MCIm switching system has a legitimate signaling relation.

                  12.4.3   BellSouth shall set message screening parameters so
                  as to accept messages destined to an MCIm local or tandem
                  switching system from any signaling point or network
                  interconnected to the BellSouth SS7 network with which the
                  MCIm switching system has a legitimate signaling relation.

                  12.4.4   BellSouth shall set message screening parameters so
                  as to accept and send messages destined to an MCIm SCP from
                  any signaling point or network interconnected to the BellSouth
                  SS7 network with which the MCIm SCP has a legitimate signaling
                  relation.

         12.5 STP REQUIREMENTS

                  12.5.1   STPs shall be equal to or better than all of the
                  requirements for STPs set forth in the following technical
                  references:

                  12.5.2   ANSI T1.111-1992 American National Standard for
                  Telecommunications - Signaling System Number 7 (SS7) - Message
                  Transfer Part (MTP);

                  12.5.3   ANSI T1.111A-1994 American National Standard for
                  Telecommunications - Signaling System Number 7 (SS7) - Message
                  Transfer Part (MTP) Supplement;

                  12.5.4   ANSI T1.112-1992 American National, Standard for
                  Telecommunications - Signaling System Number 7 (SS7) -
                  Signaling Connection Control Part (SCCP);

                  12.5.5   ANSI T1.115-1990 American National Standard for
                  Telecommunications - Signaling System Number 7 (SS7) -
                  Monitoring and Measurements for Networks;

                  12.5.6   ANSI T1.116-1990 American National Standard for
                  Telecommunications - Signaling System Number 7 (SS7) -
                  Operations, Maintenance and Administration Part (OMAP);

                  12.5.7   ANSI T1.118-1992 American National Standard for

                                                             Attachment III - 45
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  Telecommunications - Signaling System Number 7 (SS7) -
                  Intermediate Signaling Network Identification (ISNI);

                  12.5.8   Bellcore GR-905-CORE, Common Channel Signaling
                  Network Interface Specification (CCSNIS) Supporting Network
                  Interconnection, Message Transfer Part (MTP), and Integrated
                  Services Digital Network User Part (ISDNUP); and

                  12.5.9   Bellcore GR-1432-CORE, CCS Network Interface
                  Specification (CCSNIS) Supporting Signaling Connection Control
                  Part (SCCP) and Transaction Capabilities Application Part
                  (TCAP).

SECTION 13. SERVICE CONTROL POINTS/DATABASES

         13.1 DEFINITION

                  13.1.1   Databases are the Network Elements that provide the
                  functionality for storage of, access to, and manipulation of
                  information required to offer a particular service and/or
                  capability. Databases include, but are not limited to: Number
                  Portability, LIDB, Toll Free Number Database, Automatic
                  Location Identification/Data Management System, and AIN.

                  13.1.2   A Service Control Point (SCP) is a specific type of
                  Database Network Element functionality deployed in a Signaling
                  System 7 (SS7) network that executes service application logic
                  in response to SS7 queries sent to it by a switching system
                  also connected to the SS7 network. SCPs also provide
                  operational interfaces to allow for provisioning,
                  administration and maintenance of subscriber data and service
                  application data. (e.g., an 800 database stores subscriber
                  record data that provides information necessary to route 800
                  calls).

         13.2 TECHNICAL REQUIREMENTS FOR SCPS/DATABASES

         Requirements for SCPs/Databases within this section address storage of
         information, access to information (e.g. signaling protocols, response
         times), and administration of information (e.g., provisioning,
         administration, and maintenance). All SCPs/Databases shall be provided
         to MCIm in accordance with the following requirements, except where
         such a requirement is superseded by specific requirements set forth in
         Subsections 13.3 through 13.7:

                  13.2.1   BellSouth shall provide physical interconnection to
                  SCPs through the SS7 network and protocols, as specified in
                  Section 12 of this Attachment, with TCAP as the application
                  layer protocol.

                                                             Attachment III - 46
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  13.2.2   BellSouth shall provide physical interconnection to
                  databases via industry standard interfaces and protocols
                  (e.g., ISDN and X.25).

                  13.2.3   The reliability of interconnection options shall be
                  consistent with requirements for diversity and survivability
                  as specified in Section 12 of this Attachment (which applies
                  to both SS7 and non-SS7 interfaces).

                  13.2.4   Database functionality shall be unavailable a maximum
                  of 30 minutes per year.

                  13.2.5   BellSouth shall provide Database provisioning
                  consistent with the provisioning requirements of this
                  Agreement (e.g., data required, edits, acknowledgments, data
                  format and transmission medium and notification of order
                  completion).

                  13.2.6   The operational interface provided by BellSouth shall
                  complete Database transactions (i.e., add, modify, delete) for
                  MCIm subscriber records stored in BellSouth databases within
                  an interval at parity with BellSouth' s own provisioning
                  schedule..

                  13.2.7   BellSouth shall provide Database maintenance
                  consistent with the maintenance requirements as specified in
                  this Agreement (e.g., notification of BellSouth Network
                  Affecting Events, testing, dispatch schedule and measurement
                  and exception reports).

                  13.2.8   BellSouth shall provide billing and recording
                  information to track database usage consistent with
                  connectivity billing and recording requirements as specified
                  in this Agreement (e.g., recorded message format and content,
                  timeliness of feed, data format and transmission medium).

                  13.2.9   BellSouth shall provide SCPs/Databases in accordance
                  with the physical security requirements specified in this
                  Agreement.

                  13.2.10  BellSouth shall provide SCPs/Databases in accordance
                  with the logical security requirements specified in this
                  Agreement.

         13.3 NUMBER PORTABILITY DATABASE

         Permanent Number Portability (PNP) is currently being worked in
         industry forums. The results of these forums will dictate the industry
         direction of PNP. BellSouth and MCIm agree to implement PNP as directed
         by the FCC as a result of final, nonappealable orders in FCC Docket
         95-116 and the

                                                             Attachment III - 47
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         appropriate industry forums.

         13.4 LINE INFORMATION DATABASE (LIDB)

         This Subsection 13.4 defines and sets forth additional requirements for
         the Line Information Database. This Subsection 13.4 supplements the
         requirements of Subsection 13.2 and 13.7.

                  13.4.1   DEFINITION

                  The Line Information Database (LIDB) is a transaction-oriented
                  database accessible through Common Channel Signaling (CCS)
                  networks. It contains records associated with subscriber Line
                  Numbers and Special Billing Numbers (in accordance with the
                  requirements in the technical reference in Section 13.7.5).
                  LIDB accepts queries from other Network Elements, or MCIm' s
                  network, and provides appropriate responses. The query
                  originator need not be the owner of LIDB data. LIDB queries
                  include functions such as screening billed numbers that
                  provides the ability to accept Collect or Third Number Billing
                  calls and validation of Telephone Line Number based
                  non-proprietary calling cards. The interface for the LIDB
                  functionality is the interface between the BellSouth CCS
                  network and other CCS networks. LIDB also interfaces to
                  administrative systems. The administrative system interface
                  provides Work Centers with an interface to LIDB for functions
                  such as provisioning, auditing of data, access to LIDB
                  measurements and reports.

                  13.4.2   TECHNICAL REQUIREMENTS

                           13.4.2.1 Prior to the availability of a long-term
                           solution for Number Portability, BellSouth shall
                           enable MCIm to store in BellSouth's LIDB any
                           subscriber Line Number or Special Billing Number
                           record, (in accordance with the technical reference
                           in Section 13.7.5) whether ported or not, for which
                           the NPA-NXX or NXX-0/lXX Group is supported by that
                           LIDB.

                                    13.4.2.1.1 MCIm agrees that it will accept
                                    responsibility for telecommunications
                                    services billed by BellSouth for its billing
                                    and collection customers for MCIm's end
                                    user accounts which are resident in LIDB
                                    pursuant to this Agreement. MCIm authorizes
                                    BellSouth to place such charges on MCIm's
                                    bill from BellSouth and agrees that it shall
                                    pay such charges. Charges for which MCIm
                                    hereby takes responsibility include, but are
                                    not limited to, collect and third number
                                    calls.

                                                             Attachment III - 48
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    13.4.2.1.2 Charges for such services shall
                                    appear on a separate BellSouth bill page
                                    identified with the name of the entity for
                                    which BellSouth is billing the charge.

                                    13.4.2.1.3 MCIm shall have the
                                    responsibility to render a billing statement
                                    to its end users for these charges, but
                                    MCIm's obligation to pay BellSouth for the
                                    charges billed shall be independent of
                                    whether MCIm is able or not to collect from
                                    MCIm's end users.

                                    13.4.2.1.4 BellSouth shall not become
                                    involved in any disputes between MCIm and
                                    the entities for which BellSouth performs
                                    billing and collection. BellSouth will not
                                    issue adjustments for charges billed on
                                    behalf of an entity to MCIm. It shall be the
                                    responsibility of MCIm and the other entity
                                    to negotiate and arrange for any appropriate
                                    adjustments.

                           13.4.2.2 Prior to the availability of a long-term
                           solution for Number Portability, BellSouth shall
                           enable MCIm to store in BellSouth's LIDB any
                           subscriber Line Number or Special Billing Number (in
                           accordance with the technical reference in Section
                           13.7.5) record, whether ported or not, and NPA-NXX
                           and NXX-0/IXX Group Records, belonging to an NPA-NXX
                           or NXX-0/IXX owned by MCIm.

                           13.4.2.3 Prior to the availability of a long-term
                           solution for Number Portability, BellSouth shall
                           enable MCIm to store in BellSouth's LIDB any
                           subscriber Line Number or Special Billing Number (in
                           accordance with the technical reference in Section
                           13.7.5) record, whether ported or not, regardless of
                           the number's NPA-NXX or NXX-0/lXX.

                           13.4.2.4 BellSouth shall perform the following LIDB
                           functions (i.e., processing of the following query
                           types as defined in the technical reference in
                           Section 13.7.5) for MCIm's subscriber records in
                           LIDB:

                                    13.4.2.4.1 Billed Number Screening (provides
                                    information such as whether the Billed
                                    Number may accept Collect or Third Number
                                    Billing calls); and

                                    13.4.2.4.2 Nonproprietary Calling Card
                                    Validation.

                                                             Attachment III - 49
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           13.4.2.5 BellSouth shall process MCIm's subscriber
                           records in LIDB at least at parity with BellSouth
                           subscriber records, with respect to other LIDB
                           functions (as defined in the technical reference in
                           Section 13.5). BellSouth shall indicate to MCIm what
                           additional functions (if any) are performed by LIDB
                           in their network.

                           13.4.2.6 Within two (2) weeks after a request by
                           MCIm, BellSouth shall provide MCIm with a list of the
                           subscriber data items which MCIm would have to
                           provide in order to support each required LIDB
                           function. The list shall indicate which data items
                           are essential to LIDB function, and which are
                           required only to support certain services. For each
                           data item, the list shall show the data formats, the
                           acceptable values of the data item and the meaning of
                           those values.

                           13.4.2.7 BellSouth shall provide LIDB systems for
                           which operating deficiencies that would result in
                           calls being blocked, shall not exceed 30 minutes per
                           year.

                           13.4.2.8 BellSouth shall provide LIDB systems for
                           which operating deficiencies that would not result in
                           calls being blocked shall not exceed 12 hours per
                           year.

                           13.4.2.9 BellSouth shall provide LIDB systems for
                           which the LIDB function shall be in overload
                           (degraded performance in accordance with the
                           technical reference in Section 13.7.5) no more than
                           12 hours per year. Such deficiency period is in
                           addition to the periods specified in Sections
                           13.4.2.7 and 13.4.2.8 above.

                           13.4.2.10 BellSouth shall provide MCIm with the
                           capability to provision (e.g., to add, update, and
                           delete) NPA-NXX and NXX-0/IXX Group Records, and
                           Line Number and Special Billing Number Records,
                           associated with MCIm subscribers, directly into
                           BellSouth's LIDB provisioning (i.e. service order)
                           process.

                           13.4.2.11 Unless directed otherwise by MCIm, in the
                           event that end user subscribers change their local
                           service provider, BellSouth shall maintain subscriber
                           data (for line numbers, card numbers, and for any
                           other types of data maintained in LIDB) so that such
                           subscribers shall not experience any interruption of
                           service due to the lack of such maintenance of
                           subscriber data. In the event that end user
                           subscribers change their local service provider,
                           BellSouth shall use its best efforts to avoid

                                                             Attachment III - 50
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           service interruption in those situations where
                           BellSouth has control over additions and deletions in
                           the database as LIDB provider.

                           13.4.2.12 All additions, updates and deletions of
                           MCIm data to the LIDB shall be solely at the
                           direction of MCIm.

                           13.4.2.13 BellSouth shall provide, at parity,
                           priority updates to LIDB for MCIm data upon MCIm's
                           request (e.g., to support fraud protection).

                           13.4.2.14 BellSouth shall provide MCIm reports of all
                           MCIm data in LIDB.

                           13.4.2.15 Pursuant to BellSouth procedures, BellSouth
                           shall provide LIDB systems such that no more than
                           0.01% of MCIm subscriber records will be missing from
                           LIDB, as measured by MCIm audits.

                           13.4.2.16 BellSouth shall perform backup and recovery
                           of all of MCIm's data in LIDB at parity, including
                           sending to LIDB all changes made since the date of
                           the most recent backup copy.

                           13.4.2.17 BellSouth shall provide to MCIm access to
                           LIDB measurements and reports at least at parity with
                           the capability BellSouth has for its own subscriber
                           records and that BellSouth provides to any other
                           party.

                           13.4.2.18 BellSouth shall provide MCIm with LIDB
                           reports of data which are missing or contain errors,
                           as well as any misroute errors, within the time
                           period reasonably negotiated between MCIm and
                           BellSouth.

                           13.4.2.19 BellSouth shall prevent any access to or
                           use of MCIm data in LIDB by BellSouth personnel or by
                           any other party that is not authorized by MCIm in
                           writing.

                           13.4.2.20 BellSouth shall provide MCIm performance of
                           the LIDB Data Screening function, which allows a LIDB
                           to completely or partially deny specific query
                           originators access to LIDB data owned by specific
                           data owners, (in accordance with the technical
                           reference in Section 13.7.5) for Subscriber Data that
                           is part of an NPA-NXX or NXX-0/IXX wholly or
                           partially owned by MCIm at least at parity with
                           BellSouth Subscriber Data. BellSouth shall obtain
                           from MCIm the screening

                                                              Attachment II - 51
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           information associated with LIDB Data Screening of
                           MCIm data in accordance with this requirement.

                           13.4.2.21 BellSouth shall accept queries to LIDB
                           associated with MCIm subscriber records, and shall
                           return responses in accordance with the requirements
                           of this Section 13.

                           13.4.2.22 BellSouth shall provide mean processing
                           time at the LIDB within 0.50 seconds under normal
                           conditions as defined in the technical reference in
                           Section 13.7.5.

                           13.4.2.23 BellSouth shall provide processing time at
                           the LIDB within 1 second for 99% of all messages
                           under normal conditions as defined in the technical
                           reference in Section 13.7.5.

                           13.4.2.24 BellSouth shall provide 99.9 % of all LIDB
                           queries in a round trip response within 2 seconds.

                           13.4.2.25 LIDB PERFORMANCE MEASUREMENTs: BellSouth
                           shall provide LIDB performance that complies with the
                           following standards:

                                    13.4.2.25.1 BellSouth shall provide
                                    processing time at the Line Information Data
                                    Base ("LIDB") within I second for 99% of all
                                    messages under normal conditions as defined
                                    in the technical references in Section 13 of
                                    Attachment III.

                                    13.4.2.25.2 BellSouth shall provide 99.9 %
                                    of all LIDB queries in a round trip within 2
                                    seconds as defined in the technical
                                    references in Section 13 of Attachment III.

                                    13.4.2.25.3 Once appropriate data can be
                                    derived from LIDB, BellSouth shall measure
                                    the following:

                                         13.4.2.25.3.1 There shall be at least a
                                         99.9.% reply rate to all query
                                         attempts.

                                         13.4.2.25.3.2 Queries shall time out at
                                         LIDB no more than 0.1% of the time.

                                         13.4.2.25.3.3 Group troubles shall
                                         occur for no more than 1% of all
                                         LIDB queries. Group troubles include
                                         responses other than:

                                                             Attachment III - 52
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         13.4.2.25.3.3.1 Missing Group - The
                                         group is not defined in LIBD (when
                                         reply is returned "vacant" but there is
                                         no active record for the 6-digit
                                         NPA-NXX group.)

                                         13.4.2.25.3.3.2 Vacant Code - When a
                                         6-digit NPA-NXX is defined as vacant in
                                         LIDB but no active line is associated
                                         with that NPA-NXX code.

                                         13.4.2.25.3.4 Once MCIm requests LIDB
                                         screening pursuant to Section 13 of
                                         Attachment III, the Parties shall
                                         negotiate the appropriate performance
                                         standard for defects in LIDB Data
                                         Screening of responses.

                           13.4.2.26 BellSouth shall provide data in LIDB
                           replies with no more than 2% unexpected data values.
                           Per BellCore document SR334, because the majority of
                           the error (i.e., fraud attempts, customer or operator
                           misdialing, and CPE malfunctions are beyond the LIDB
                           owner, Unexpected Data Value - PIN Mismatch should
                           not be considered measurement of BellSouth LIDB
                           quality. However, should this value exceed 2% MCIm
                           and BellSouth will jointly agree if and when root
                           cause analysis is necessary.

                  13.4.3   INTERFACE REQUIREMENTS -

                  BellSouth shall offer LIDB in accordance with the requirements
                  of this subsection 13.4.3.

                           13.4.3.1 The interface to LIDB shall be in accordance
                           with the technical reference in Section 13.7.3.

                           13.4.3.2 The CCS interface to LIDB shall be the
                           standard interface described in Section 13.7.3.

                           13.4.3.3 The LIDB Data Base interpretation of the
                           ANSI-TCAP messages shall comply with the technical
                           reference in Section 13.7.4. Global Title Translation
                           shall be maintained in the signaling network in order
                           to support signaling network routing to the LIDB.

                                                             Attachment III - 53
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         13.5 TOLL FREE NUMBER DATABASE

         The Toll Free Number Database is a SCP that provides functionality
         necessary for toll free (e.g., 800 and 888) number services by
         providing routing information and additional so-called vertical
         features during call set-up in response to queries from SSPs. This
         Subsection 13.5 supplements the requirements of Subsection 13.2 and
         13.7. BellSouth shall provide the Toll Free Number Database in
         accordance with the following:

                  13.5.1   TECHNICAL REQUIREMENTS

                           13.5.1.1 BellSouth shall make the BellSouth Toll Free
                           Number Database available for MCIm to query, from
                           MCIm's designated switch including BellSouth
                           unbundled local switching, with a toll-free number
                           and originating information.

                           13.5.1.2 The Toll Free Number Database shall return
                           carrier identification and, where applicable, the
                           queried toll free number, translated numbers and
                           instructions as it would in response to a query from
                           a BellSouth switch.

                           13.5.1.3 The SCP shall also provide, at MCIm's
                           option, such additional features as described in
                           SR-TSV-002275 (BOC Notes on the BellSouth Networks,
                           SR-TSV-002275, Issue 2, (Bellcore, April 1994)) as
                           are available to BellSouth. These may include but are
                           not limited to:

                                    13.5.1.3.1 Network Management;

                                    13.5.1.3.2 Subscriber Sample Collection, at
                                    charges set forth in Attachment I; and

                                    13.5.1.3.3 Service Maintenance.

                  13.5.2   INTERFACE REQUIREMENTS

                  The signaling interface between the MCIm or other local switch
                  and the Toll-Free Number database shall use the TCAP protocol
                  as specified in the technical reference in Section 13.7.1,
                  together with the signaling network interface as specified in
                  the technical reference in Sections 13.7.2 and 13.7.6.

         13.6 AUTOMATIC LOCATION IDENTIFICATION/DATA MANAGEMENT SYSTEM (ALI/DMS)

                                                             Attachment III - 54
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         The ALI/DMS Database contains subscriber information (including name,
         address, telephone information, and sometimes special information from
         the local service provider or subscriber) used to determine to which
         Public Safety Answering Point (PSAP) to route the call. The ALI/DMS
         database is used to provide more routing flexibility for E911 calls
         than Basic 911. This Subsection 13.6 supplements the requirements of
         Subsection 13.7.2 and 13.7.6. BellSouth shall provide the Emergency
         Services Database in accordance with the following:

                  13.6.1   TECHNICAL REQUIREMENTS

                           13.6.1.1 BellSouth shall offer MCIm a data link to
                           the ALI/DMS database or permit MCIm to provide its
                           own data link to the ALI/DMS database.

                           BellSouth shall provide error reports from the
                           ALI/DMS data base to MCIm after MCIm inputs
                           information into the ALI/DMS data base. Alternately,
                           MCIm may utilize BellSouth to enter through the
                           service order process subscriber information into the
                           data base on a demand basis, and validate subscriber
                           information on a demand basis.

                           13.6.1.2 The ALI/DMS database shall contain the
                           following subscriber information:

                                    13.6.1.2.1 Name;

                                    13.6.1.2.2 Address;

                                    13.6.1.2.3 Telephone number; and

                                    13.6.1.2.4 Other information as BellSouth
                                    deems appropriate

                           13.6.1.3 When BellSouth is responsible for
                           administering the ALI/DMS database in its entirety,
                           ported number NXXs entries for the ported numbers
                           should be maintained unless MCIm requests otherwise
                           and shall be updated if MCIm requests.

                           13.6.1.4 When Remote Call Forwarding (RCF) is used to
                           provide number portability to the local subscriber
                           and a remark or other appropriate field information
                           is available in the database, the shadow or
                           "forwarded-to" number and an indication that the
                           number is ported shall be added to the subscriber
                           record.

                                                             Attachment III - 55
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           13.6.1.5 If BellSouth is responsible for configuring
                           PSAP features for cases when the PSAP or BellSouth
                           supports an ISDN interface) it shall ensure that
                           CLASS Automatic Recall (Call Return) is not used to
                           call back to the ported number.

                  13.6.2   INTERFACE REQUIREMENTS -

                           13.6.2.1 The interface between the E911 Switch or
                           Tandem and the ALI/DMS database for MCIm subscribers
                           shall meet industry standards.

         13.7 Where Technically Feasible, SCPs/Databases shall be equal to or
         better than all of the requirements for SCPs/Databases set forth in the
         following technical references:

                  13.7.1   GR-246-CORE, Bell Communications Research
                  Specification of Signaling System Number 7, ISSUE 1 (Bellcore,
                  December 199);

                  13.7.2   GR-1432-CORE, CCS Network Interface Specification
                  (CCSNIS) Supporting Signaling Connection Control Part (SCCP)
                  and Transaction Capabilities Application Part (TCAP).
                  (Bellcore, March 1994);

                  13.7.3   GR-954-CORE, CCS Network Interface Specification
                  (CCSNIS) Supporting Line Information Database (LIDB) Service
                  6, Issue 1, Rev. 1 (Bellcore, October 1995);

                  13.7.4   GR-1149-CORE, OSSGR Section 10: System Interfaces,
                  Issue 1 (Bellcore, October 1995) (Replaces TR-NWT-001149);

                  13.7.5   GR-1158-CORE, OSSGR Section 22.3: Line Information
                  Database 6, Issue (Bellcore, October 1995)

                  13.7.6   GR-1428-CORE, CCS Network Interface Specification
                  (CCSNIS) Supporting Toll Free Service (Bellcore, May 1995);
                  and

                  13.7.7   "Bellcore Special Report SR-TSV-002275, IBOC Notes on
                  the LEC Networks - Signaling".

         13.8 ADVANCED INTELLIGENT NETWORK (AIN) ACCESS, SERVICE CREATION
         ENVIRONMENT AND SERVICE MANAGEMENT SYSTEM (SCE/SMS) ADVANCED
         INTELLIGENT NETWORK ACCESS

                  13.8.1   BellSouth will make all BellSouth SCP-based AIN
                  retail

                                                             Attachment III - 56
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  services available for resale to MCIm. MCIm will be given the
                  opportunity to develop competitive AIN 0.1 service
                  applications via unbundled access to BellSouth's SCE/SMS.
                  Where Technically Feasible, access to BellSouth resold
                  services and MCIm created services may be supported from both
                  MCIm and BellSouth local switches.

                  13.8.2   SCE/SMS AIN Access shall provide MCIm the ability to
                  create service applications utilizing BellSouth AIN 0.1
                  service creation tools and deploy those applications via the
                  BellSouth SMS to the BellSouth SCPs. Through traditional
                  mechanisms, MCIm will be supported in provisioning switch
                  triggers in BellSouth local switches which will access these
                  applications. AIN SCE/SMS service development capabilities
                  provided to MCIm will provide the same AIN 0.1 service
                  development opportunities as presented to BellSouth in
                  utilization of its basic AIN programmability tools (DesignEdge
                  service). See Figure 7 below.

                           13.8.2.1 BellSouth will participate in standards
                           bodies actively pursuing SMS/SCE standards. If
                           standards are adopted in this area, BellSouth will
                           seek to evolve its AIN SMS/SCE access toward such
                           standards.

                               [GRAPHIC OMITTED]

                                    FIGURE 7

                  13.8.3   BellSouth's SCE/SMS offering shall provide access to
                  SCE

                                                             Attachment III - 57
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  hardware, software, testing and technical support (e.g., help
                  desk, system administrator) resources available to MCIm on a
                  reasonable basis. Scheduling procedures shall provide MCIm
                  equal priority access to these resources.

                  13.8.4   AIN access BellSouth shall allow for multi-user
                  access with proper source code management and other logical
                  security functions as specified in the Security section of
                  this Agreement.

                  13.8.5   The BellSouth SCP shall partition and protect MCIm
                  service logic and data from unauthorized access, execution or
                  other types of compromise.

                  13.8.6   When MCI selects SCE/SMS AIN access, BellSouth shall
                  provide adequate training, documentation, and technical
                  support of MCIm development staff to reasonably expect
                  successful application development. Such training shall
                  address use of SCE/SMS AIN access and administrative
                  functions, but will not include support for creation of a
                  specific service application.

                  13.8.7   BellSouth will provide a secure controlled access
                  environment in association with its internal utilization of
                  AIN components. When MCIm utilizes BellSouth's SCE/SMS, AIN
                  Access will be provided via remote data connections (e.g.,
                  dial up, LAN, WAN) to published specifications.

                  13.8.8   When MCIm selects SCE/SMS AIN Access, BellSouth shall
                  allow MCIm to download data forms and/or tables to the
                  BellSouth SCP via the BellSouth SMS without intervention from
                  BellSouth (e.g., service customization and subscriber
                  subscription). 13.8.9 BellSouth shall offer, through the
                  SCE/SMS AIN Access, access to the SCPs/Databases for control
                  of MCIm end user functionality.

SECTION 14. TANDEM SWITCHING

         14.1 DEFINITION

         Tandem Switching is the function that establishes a communications path
         between two switching offices through a third switching office (the
         tandem switch). BellSouth shall provide MCIm with selective routing via
         Line Class Codes. Further, MCIm and BellSouth shall continue to work
         with the appropriate industry groups to develop a long term solution
         for selective routing.

                                                             Attachment III - 58
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         14.2 TECHNICAL REQUIREMENTS

                  14.2.1   Tandem Switching shall have the same capabilities or
                  equivalent capabilities as those described in Bell
                  Communications Research TR-TSY-000540 Issue 2R2, Tandem
                  Supplement, 6/l/90. The requirements for Tandem Switching
                  include, but are not limited to, the following:

                           14.2.1.1 Tandem Switching shall provide signaling to
                           establish a tandem connection;

                           14.2.1.2 Subject to section 14.1, above, Tandem
                           Switching shall provide screening and routing as
                           designated by MCIm;

                           14.2.1.3 Tandem Switching shall provide recording of
                           all billable events designated by MCIm;

                           14.2.1.4 When Technically Feasible, and requested via
                           BFR by MCIm, Tandem Switching shall provide Advanced
                           Intelligent Network triggers supporting AIN features;

                           14.2.1.5 Subject to section 14.1, above, Tandem
                           Switching shall provide connectivity to Operator
                           Systems as designated by MCIm;

                           14.2.1.6 Tandem Switching shall provide access to
                           Toll Free number portability database as designated
                           by MCIm;

                           14.2.1.7 Tandem Switching shall provide all trunk
                           interconnections discussed under the "Network
                           Interconnection" section (e.g., SS7, MF, DTMF, Dial
                           Pulse, PRI-ISDN, DID, and CAMA-ANI (if appropriate
                           for 911));

                           14.2.1.8 Tandem Switching shall provide connectivity
                           to PSAPs where 911 solutions are deployed and the
                           tandem is used for 911; and

                           14.2.1.9 Tandem Switching shall provide connectivity
                           to transit traffic to and from other carriers.

                  14.2.2   Tandem Switching shall accept connections (including
                  the necessary signaling and trunking interconnections) between
                  end offices, other tandems, IECs, ICOs, CAPs and CLEC
                  switches.

                                                             Attachment III - 59
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  14.2.3   Tandem Switching shall provide local tandeming
                  functionality between two end offices including two offices
                  belonging to different CLEC's (e.g., between an MCIm end
                  office and the end office of another CLEC).

                  14.2.4   Tandem Switching shall preserve CLASS/LASS features
                  and Caller ID as traffic is processed. Additional signaling
                  information and requirements are provided in Section 12.

                  14.2.5   Tandem Switching shall record billable events and
                  send them to the area billing centers designated by MCIm.
                  Billing requirements are specified in Attachment 8 of this
                  Agreement.

                  14.2.6   Upon reasonable request, BellSouth shall perform
                  routine testing and fault isolation on the underlying switch
                  that is providing Tandem Switching and all its
                  interconnections. When requested by MCIm, the results and
                  reports of the testing shall be made immediately available to
                  MCIm.

                  14.2.7   When requested by MCIm, BellSouth shall provide
                  performance data regarding traffic characteristics or other
                  measurable elements to MCIm for review.

                  14.2.8   Tandem Switching shall be capable of controlling
                  congestion using capabilities such as Automatic Congestion
                  Control (e.g. choke trunk groups) and Network Routing
                  Overflow. Congestion control provided or imposed on MCIm
                  traffic shall be at parity with controls being provided or
                  imposed on BellSouth traffic (e.g., BellSouth shall not block
                  MCIm traffic in a discriminatory manner.

                  14.2.9   Subject to section 14.1, above, Tandem Switching
                  shall route calls to BellSouth or MClm endpoints or platforms
                  (e.g., operator services and PSAPs) on a per call basis as
                  designated by MClm. Detailed primary and overflow routing
                  plans for all interfaces available within the BellSouth
                  switching network shall be mutually agreed to by MClm and
                  BellSouth. Such plans shall meet reasonable MCIm requirements
                  for routing calls through the local network.

                  14.2.10  Tandem Switching shall process originating toll-free
                  traffic received from an MCIm local switch.

                  14.2.11  In support of AIN triggers and features, Tandem
                  Switching, when Technically Feasible and requested via BFR by
                  MCIm, shall provide SSP capabilities when these capabilities
                  are not available from the Local Switching Network Element.

                                                             Attachment III - 60
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  14.2.12  The Local Switching and Tandem Switching functions
                  may be combined in an office. If this is done, both Local
                  Switching and Tandem switching shall provide all of the
                  functionality required of each of those Network Elements in
                  this Agreement.

         14.3 INTERFACE REQUIREMENTS

                  14.3.1   Tandem Switching shall provide interconnection to the
                  E911 PSAP where the underlying Tandem is acting as the E911
                  Tandem.

                  14.3.2   Tandem Switching shall interconnect, with direct
                  trunks, to all carriers with which BellSouth interconnects.

                  14.3.3   BellSouth shall provide all signaling necessary to
                  provide Tandem Switching with no loss of feature
                  functionality.

                  14.3.4   Tandem Switching shall interconnect with MCIm's
                  switch, using two-way trunks, for traffic that is transiting
                  via the BellSouth network to interLATA or intraLATA carriers.
                  At MCIm's request, Tandem Switching shall record and keep
                  records of traffic for billing.

                  14.3.5   Tandem Switching shall provide an alternate final
                  routing pattern for MCIm traffic overflowing from direct end
                  office high usage trunk groups.

         14.4 Tandem Switching shall meet or exceed (i.e., be more favorable to
         MCIm) each of the requirements for Tandem Switching set forth in the
         following technical references:

                  14.4.1   Bell Communications Research TR-TSY-000540 Issue 2R2,
                  Tandem Supplement, 6/l/90;

                  14.4.2   GR-905-CORE covering CCSNIS;

                  14.4.3   GR-1429-CORE for call management features; and
                  GR-2863-CORE and GR-2902-CORE covering CCS AIN
                  interconnection.

SECTION 15. ADDITIONAL REQUIREMENTS

This Section 15 of Attachment III sets forth the additional requirements for
unbundled Network Elements which BellSouth agrees to offer to MCIm under this
Agreement.

         15.1 COOPERATIVE TESTING

                                                             Attachment III - 61
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  15.1.1   DEFINITION

                  Cooperative Testing means that BellSouth shall cooperate with
                  MCIm upon request or as needed to (1) ensure that the Network
                  Elements and Ancillary Functions and additional requirements
                  being provided to MCIm by BellSouth are in compliance with the
                  requirements of this Agreement, (2) test the overall
                  functionality of various Network Elements and Ancillary
                  Functions provided by BellSouth to MCIm in combination with
                  each other or in combination with other equipment and
                  facilities provided by MCIm or third parties, and (3) ensure
                  that all operational interfaces and processes are in place and
                  functioning properly and efficiently for the provisioning and
                  maintenance of Network Elements and Ancillary Functions and so
                  that all appropriate billing data can be provided to MCIm.

                  15.1.2   REQUIREMENTS

                  Within ninety (90) days of the Effective Date of this
                  Agreement, MCIm and BellSouth will agree upon a process to
                  resolve technical issues relating to interconnection of MCIm's
                  network to BellSouth's network and Network Elements and
                  Ancillary Functions. The agreed upon process shall include
                  procedures for escalating disputes and unresolved issues up
                  through higher levels of each company's management. If MCIm
                  and BellSouth do not reach agreement on such a process within
                  ninety (90) days, any issues that have not been resolved by
                  the parties with respect to such process shall be submitted to
                  the procedures set forth in Part A Section 23 of this
                  Agreement unless both parties agree to extend the time to
                  reach agreement on such issues.

                           15.1.2.1 BellSouth shall provide MCIm access for
                           testing at any interface between a BellSouth Network
                           Element or combinations and MCIm equipment or
                           facilities. Such test access shall be sufficient to
                           ensure that the applicable requirements can be tested
                           by MCIm. This access shall be available seven (7)
                           days per week, 24 hours per day.

                           15.1.2.2 MCIm may test any interfaces, Network
                           Elements or Ancillary Functions and additional
                           requirements provided by BellSouth pursuant to this
                           Agreement.

                           15.1.2.3 BellSouth shall provide engineering data as
                           requested by MCIm for the loop components as set
                           forth in Sections 2, 3 and 4 of this Attachment which
                           MCIm may desire to test. Such

                                                             Attachment III - 62
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           data shall include equipment engineering and cable
                           specifications, signaling and transmission path data.

                           15.1.2.4 Upon MCIm's request, to the extent required
                           by applicable Commission orders or by subsequent
                           agreement, BellSouth shall provide to MCIm any office
                           records, central office layout and design records and
                           drawings, system engineering and other applicable
                           documentation pertaining to a Network Element or
                           Ancillary Function or the underlying equipment that
                           is then providing a Network Element or Ancillary
                           Function to MCIm.

                           15.1.2.5 BellSouth shall provide to MCIm upon
                           request, all applicable test results, from BellSouth
                           testing activities on a Network Element or Ancillary
                           Function or Additional Requirement or the underlying
                           equipment providing a Network Element or Ancillary
                           Function or Additional Requirements. MCIm may review
                           such testing results and may notify BellSouth of any
                           deficiencies that are detected.

                           15.1.2.6 BellSouth shall temporarily provision MCIm
                           designated Local Switching. Within ninety (90) days
                           of the Effective Date of this Agreement, MCIm and
                           BellSouth shall mutually agree on the procedures to
                           be established between BellSouth and MCIm to expedite
                           such provisioning processes for feature testing.

                           15.1.2.7 Upon MCIm's request, BellSouth shall provide
                           technical staff to meet with MCIm representatives to
                           provide required support for Cooperative Testing.

                           15.1.2.8 Dedicated Transport and Loop Feeder may
                           experience alarm conditions due to in-progress tests.
                           BellSouth shall not remove such facilities from
                           service without obtaining MCIm's prior approval.

                           15.1.2.9 BellSouth shall get acceptance from MCIm
                           prior to conducting tests or maintenance procedures
                           on Network Elements or Ancillary Functions or on the
                           underlying equipment that is then providing a Network
                           Element or Ancillary Function, that may cause a
                           service interruption or degradation of service

                           15.1.2.10 BellSouth shall provide a single point of
                           contact to MCIm that is available 7 days per week, 24
                           hours per day for trouble status, sectionalization,
                           resolution, escalation, and

                                                             Attachment III - 63
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           closure. Such staff shall be adequately skilled to
                           allow expeditious problem resolution.

                           15.1.2.11 BellSouth shall provide to MCIm electronic
                           access to 105 responders, 100-type test lines, or
                           102-type test lines associated with any circuits
                           under test.

                           15.1.2.12 BellSouth shall participate in Cooperative
                           Testing with MCIm upon MCIm's request to test any
                           operational interface or process used to provide
                           Network Elements, Ancillary Functions or Services to
                           MCIm.

                           15.1.2.13 MCIm and BellSouth shall endeavor to
                           complete Cooperative Testing as stated in Attachment
                           8.

                           15.1.2.14 BellSouth shall participate in Cooperative
                           Testing requested by MCIm whenever it is deemed
                           necessary by MCIm to insure service performance,
                           reliability and subscriber erviceability.

                           15.1.2.15 MCIm may accept or reject the Network
                           Element ordered by MCIm if, upon completion of
                           cooperative acceptance testing, the tested Network
                           Element does not meet the requirements stated herein.

                           15.1.2.16 BellSouth shall provide real-time, remote
                           data access, where available to performance
                           monitoring and alarm data on events affecting (or
                           potentially affecting) MCIm's traffic on BellSouth' s
                           network elements.

         15.2 PERFORMANCE

                  15.2.1   SCOPE

                  This section addresses performance requirements for Network
                  Elements and Ancillary Functions to provide local service. It
                  includes requirements for the reliability and availability of
                  Network Elements and Ancillary Functions, and quality
                  parameters such as transmission quality (analog and digital),
                  and speed (or delay). In addition, an overview of service
                  performance requirements is given. These requirements shall
                  apply to the extent they are in conformance with, and
                  applicable to BellSouth under, accepted industry standards,
                  and MCI may request more stringent performance standards, if
                  Technically Feasible, via the bona fide request process.

                                                             Attachment III - 64
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           15.2.1.1 The General Performance Requirements in this
                           section apply to all aspects of Network Elements and
                           Ancillary Functions. Additional requirements are
                           given in this performance section and in the
                           individual Network Elements sections.

                           15.2.1.2 BellSouth shall work cooperatively with MCIm
                           to determine appropriate performance allocations
                           across Network Elements.

                  15.2.3   BellSouth shall provide performance equal to or
                  better than all of the requirements set forth in the following
                  technical references:

                           15.2.3.1 BELL COMMUNICATIONS RESEARCH, INC. DOCUMENTS

                                    15.2.3.1.1 FR-64, LATA Switching Systems
                                    Generic Requirements (LSSGR). This document
                                    contains 117 Technical References and
                                    Generic Requirements. Sections provide the
                                    requirements for local switching systems
                                    (also referred to as end offices) that serve
                                    subscribers' lines. Some modules of the
                                    LSSGR are also referenced separately in this
                                    document.

                                    15.2.3.1.2 TR-NWT-000499, Issue 5, Rev 1,
                                    April 1992, Transport Systems Generic
                                    Requirements (TSGR): Common Requirements.

                                    15.2.3.1.3 TR-NWT-000418, Issue 2, December
                                    1992, Generic Reliability Assurance
                                    Requirements For Fiber Optic Transport
                                    Systems.

                                    15.2.3.1.4 TR-NWT-000057, Issue 2, January
                                    1993, Functional Criteria for Digital Loop
                                    Carriers Systems.

                                    15.2.3.1.5 TR-NWT-000507, Issue 5, December
                                    1993, LSSGR - Transmission, Section 7.

                                    15.2.3.1.6 GR-303-CORE, Issue 1, September
                                    1995, Integrated Digital Loop Carrier System
                                    Generic Requirements, Objectives, and
                                    Interface.

                                    15.2.3.1.7 GR-334-CORE, Issue 1, June 1994,
                                    Switched Access Service: Transmission
                                    Parameter Limits and Interface Combinations.

                                                             Attachment III - 65
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    15.2.3.1.8 TR-NWT-000335, Issue 3, May 1993,
                                    Voice Grade Special Access Services -
                                    Transmission Parameter Limits and Interface
                                    Combinations.

                                    15.2.3.1.9 TR-TSY-000529, Issue 2, July
                                    1987, Public Safety - LSSGR.

                                    15.2.3.1.10 GR-1158-CORE, Issue 2, October
                                    1995, OSSGR Section 22.3: Line Information
                                    Database.

                                    15.2.3.1.11 TR-TSY-000511, Issue 2, July
                                    1987, Service Standards, a Module (Section
                                    11) of LATA Switching Systems Generic
                                    Requirements (LSSGR, FR-NWT-000064).

                                    15.2.3.1.12 TR-NWT-000393, January 1991,
                                    Generic Requirements for ISDN Basic Access
                                    Digital Subscriber Lines.

                                    15.2.3.1.13 TR-NWT-000909, December 1991,
                                    Generic Requirements and Objectives for
                                    Fiber In The Loop Systems.

                                    15.2.3.1.14 TR-NWT-000505, Issue 3, May
                                    1991, LSSGR Section 5, Call Processing.

                                    15.2.3.1.15 FR-NWT-000271, 1993, Operator
                                    Services Systems Generic Requirements
                                    (OSSGR).

                                    15.2.3.1.16 TR-NWT-001156, Issue 2, July
                                    1993, OSSGR Operator Services Systems
                                    Generic Requirements, Section 21, Operator
                                    Subsystem.

                                    15.2.3.1.17 SR-TSY-001 171, Issue 1, January
                                    1989, Methods and Procedures for System
                                    Reliability Analysis.

                                    15.2.3.1.18 Bellcore Telecommunications
                                    Transmission Engineering, 3rd Ed, 1990.

                           15.2.3.2 ANSI STANDARDS

                                    15.2.3.2.1 ANSI T1.512-1994, Network
                                    Performance - Point-to-Point Voice-Grade
                                    Special Access Network Voiceband Data
                                    Transmission Objectives.

                                                             Attachment III - 66
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    15.2.3.2.2 ANSI T1.506-1990, Network
                                    Performance - Transmission Specifications
                                    for Switched Exchange Access Network.

                                    15.2.3.2.3 ANSI T1.508-1992,
                                    Telecommunications - Network Performance -
                                    Loss Plan for Evolving Digital Networks.
                                    Also supplement T1.508a-1993.

                                    15.2.3.2.4 ANSI T1.101-1994, Digital
                                    Synchronization Network Plan.

                           15.2.3.3 TIA/EIA STANDARDS

                                    15.2.3.3.1 Requirements not specifically
                                    addressed here shall be found in the
                                    documents listed in Electronic Industries
                                    Association/Telecommunications Industries
                                    Association Standards and Engineering
                                    Publications.

                                    15.2.3.3.2 TIA/EIA TSB-37A, Telephone
                                    Network Transmission Model for Evaluating
                                    Modem Performance.

                                    15.2.3.3.3 TIA/EIA TSB-38, Test Procedure
                                    for Evaluation of 2-wire 4 kHz Voiceband
                                    Duplex Modems.

                           15.2.3.4 IEEE STANDARDS

                                    15.2.3.4.1 IEEE Standard 743-1984, IEEE
                                    Standard Methods and Equipment for Measuring
                                    Transmission Characteristics of Analog Voice
                                    Frequency Circuits.

                                    15.2.3.4.2 ANSI/IEEE Standard 820-1984,
                                    Telephone Loop Performance Characteristics.

                  15.2.4   SERVICES AND CAPABILITIES

                           15.2.4.1 All Network Elements shall provide
                           performance sufficient, in combination with other
                           Network Elements, to provide the following
                           applications in accordance with the requirements of
                           this document:

                                    15.2.4.1.1 All types of voice services.

                                    15.2.4.1.2 Voice-band data modem connections
                                    up to 9.6 kbps and up to and including 28.8
                                    kbps V.34 when available.

                                                             Attachment III - 67
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    15.2.4.1.3 All types of FAX transmissions up
                                    to and including 14.4 Kbps group 3.

                                    15.2.4.1.4 All CLASS/LASS features.

                                    15.2.4.1.5 All Operator Systems.

                           15.2.4.2 The following capabilities shall be provided
                           as applicable:

                                    15.2.4.2.1 ISDN BRI

                                    15.2.4.2.2 ISDN PRI

                                    15.2.4.2.3 Switched Digital Data

                                    15.2.4.2.4 Non-Switched Digital Data

                                    15.2.4.2.5 Any types of Video applications
                                    that a subscriber may order

                                    15.2.4.2.6 Any Coin Services the subscriber
                                    may order

                                    15.2.4.2.7 Frame Relay and ATM

                                    15.2.4.2.8 Private Line Services

                  15.2.5   Specific Performance Requirements for Network
                  Elements and Ancillary Functions

                           15.2.5.1 The following sections itemize performance
                           parameters for Network Elements and Ancillary
                           Functions. BellSouth shall provide performance equal
                           to or better than all of the requirements set forth
                           in this Section. Unless noted otherwise, requirements
                           and objectives are given in terms of specific limits.
                           This means that all tests (acceptance and ongoing
                           performance) shall meet the limit(s) to satisfy the
                           requirement.

                           15.2.5.2 PERFORMANCE ALLOCATION

                                    15.2.5.2.1 Transmission path impairments may
                                    be classified as either analog or digital,
                                    and will depend on the nature of the signal
                                    transmitted across the Network

                                                             Attachment III - 68
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    Element. Analog impairments are introduced
                                    on any analog portion of the loop, typically
                                    between the NID portion of Loop Distribution
                                    and the analog to digital (A/D) conversion,
                                    and are usually correlated with the length
                                    of the physical plant. Digital impairments
                                    are introduced by A/D conversion and by
                                    interfaces between digital Network Elements.
                                    In addition, noise can be introduced by
                                    either analog transmission or the A/D
                                    conversion.

                           15.2.5.3 LOOP COMBINATION ARCHITECTURE CONSTRAINTS

                                    15.2.5.3.1 The following constraints will
                                    limit not only the variety of Loop
                                    Combination architectures that may be
                                    considered, but also the architectures
                                    BellSouth may consider to deliver any
                                    Ancillary Function or Network Element. These
                                    constraints apply to the entire path between
                                    the NID portion of Loop Distribution and the
                                    BellSouth switch. Any exceptions to these
                                    restrictions shall be specifically requested
                                    or approved by MCIm in writing.

                                         15.2.5.3.1.1 Left Blank Intentionally.

                                         15.2.5.3.1.2 No more than 1,
                                         2-to-4-wire hybrid.

                                         15.2.5.3.1.3 No voice compression.

                                         15.2.5.3.1.4 No echo canceled or
                                         suppressers.

                                         15.2.5.3.1.5 One digital loss pad per
                                         PBX.

                                         15.2.5.3.1.6 No digital gain.

                                         15.2.5.3.1.7 No additional equipment
                                         that might significantly increase
                                         intermodulation distortion.

                           15.2.5.4 TRANSMISSION IMPAIRMENTS

                                    15.2.5.4.1 ANALOG IMPAIRMENTS

                                         15.2.5.4.1.1 Analog impairments are
                                         those introduced on portions of the
                                         end-to-end circuit on which
                                         communications signals are transmitted
                                         in analog format. These portions of the
                                         transmission

                                                             Attachment III - 69
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         path would typically be between NID and
                                         an A/D conversion, most commonly on the
                                         metallic loop. The performance on the
                                         analog portion of a circuit is
                                         typically inversely proportional to the
                                         length of that circuit.

                                         15.2.5.4.1.2 LOSS

                                            15.2.5.4.1.2.1 Electrical loss is
                                            measured using a 1004 Hz 0.0 DB one
                                            Milliwatt 900 ohm test tone.

                                            15.2.5.4.1.2.2 Off-hook electrical
                                            loss between the NID and the switch
                                            shall be no more than 8.0 dB for any
                                            line, and the mean value for all
                                            lines shall be 3.5 dB "0.5 dB.
                                            On-hook electrical loss between the
                                            NID and the switch shall be no more
                                            than 4.0 dB above the off-hook
                                            electrical loss for any line.

                                         15.2.5.4.1.3 IDLE CHANNEL CIRCUIT NOISE

                                            15.2.5.4.1.3.1 Idle channel circuit
                                            noise (C-message) is added by analog
                                            facilities, by the A/D conversion of
                                            signals, by digital processing
                                            equipment (e.g., echo cancelers,
                                            digital loss pads), robbed bit
                                            signaling, and errors on digital
                                            facilities.

                                            15.2.5.4.1.3.2 Idle channel circuit
                                            noise shall be less than or equal to
                                            18 dBrnC.

                                         15.2.5.4.1.4 TALKER ECHO

                                            15.2.5.4.1.4.1 The primary source of
                                            echo is improper impedance-matching
                                            at the 2-to-4 wire hybrid in the
                                            BellSouth network. The impact on
                                            subscriber perception is a function
                                            of both echo return loss and delay.

                                            15.2.5.4.1.4.2 Echo Return Loss
                                            (ERL) shall be greater than 26 dB to
                                            a standard termination (900 ohms,
                                            2.16 mFd), and greater than 14 dB to
                                            a telephone set off-

                                                             Attachment III - 70
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                            hook. Singing Return Loss (SRL)
                                            shall be greater than 2l dB to a
                                            standard termination, and greater
                                            than 11 dB to a telephone set
                                            off-hook.

                                         15.2.5.4.1.5 LISTENER ECHO

                                         Listener echo is a double reflection of
                                         a transmitted signal at two different
                                         impedance mismatches in the end-to-end
                                         connection. While in extreme cases it
                                         can degrade voice transmission
                                         performance, listener echo is primarily
                                         an issue for voiceband data. The
                                         requirements on Talker Echo shall apply
                                         to Listener Echo.

                                         15.2.5.4.1.6 PROPAGATION AND PROCESSING
                                         DELAY

                                            15.2.5.4.1.6.1 Propagation delay is
                                            the delay involved in transmitting
                                            information from one location to
                                            another. It is caused by processing
                                            delays of equipment in the network
                                            and delays associated with traveling
                                            across transmission facilities.

                                            15.2.5.4.1.6.2 BellSouth shall
                                            cooperate with MCIm to limit total
                                            service propagation and processing
                                            delay to levels at parity with that
                                            within the BellSouth local network.

                                         15.2.5.4.1.7 SIGNAL-TO-NOISE RATIO

                                            15.2.5.4.1.7.1 The Signal-to-Noise
                                            Ratio (S/N) is a critical parameter
                                            in determining voiceband data
                                            performance. It is typically
                                            measured with a 1004 Hz tone.

                                            15.2.5.4.1.7.2 BellSouth must
                                            provide on the Loop Combination a
                                            signal-to-noise ratio of at least 37
                                            dB between the NID and the end
                                            office.

                                         15.2.5.4.1.8 C-NOTCHED NOISE: The
                                         requirements for Signal-to-Noise Ratio
                                         shall apply to C-Notched Noise.

                                                             Attachment III - 71
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         15.2.5.4.1.9 ATTENUATION DISTORTION

                                            15.2.5.4.1.9.1 Attenuation
                                            distortion, also known as frequency
                                            distortion or gain slope, measures
                                            the variations in loss at different
                                            frequencies across the voice
                                            frequency spectrum (200 Hz - 3400
                                            Hz). It is measured by subtracting
                                            the loss at 1004 Hz from the loss at
                                            the frequency of interest.

                                            15.2.5.4.1.9.2 Attenuation
                                            distortion from the NID to the
                                            switch shall be within the range
                                            +/-0.5 dB for frequencies between
                                            304 and 3004 Hz; from the switch to
                                            NID attenuation distortion shall be
                                            within the range +/- 0.5 dB for
                                            frequencies between 204 Hz and 3004
                                            Hz. In addition, attenuation
                                            distortion shall remain within the
                                            range +1 dB/-3 dB for frequencies
                                            between 200 Hz and 3500 Hz.

                                         15.2.5.4.1.10 ENVELOPE DELAY DISTORTION

                                            15.2.5.4.1.10.1 Envelope Delay
                                            Distortion (EDD) measures the
                                            difference in transit time of
                                            signals at different frequencies.
                                            EDD is measured relative to the
                                            transit time of a 1704 Hz tone, and
                                            is given in microseconds. EDD is
                                            used as an approximation of the
                                            group delay of the channel.

                                            15.2.5.4.1.10.2 EDD shall be: 1704
                                            Hz to 604 Hz3/4(pound)350 msec.;
                                            1704 Hz to 2804 Hz 3/4(pound)195
                                            msec.; 1704 Hz to 204 Hz3/4(pound)
                                            580 msec.; 1704 Hz to 3404 Hz3/4
                                            (pound)400 msec.

                                         15.2.5.4.1.11 PHASE JITTER

                                            15.2.5.4.1.11.1 Phase jitter
                                            measures the unwanted angular
                                            modulation of a signal. It is caused
                                            by noise or the actual modulation

                                                             Attachment III - 72
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                            of thesignal by another unwanted
                                            signal. It displaces the zero
                                            crossings of a signal. It is
                                            measured in terms of peak-to-peak
                                            deviations of a 1004 Hz tone from
                                            its nominal zero crossings, and
                                            in a particular frequency band
                                            (200-300 HZ and either 4-300 Hz or
                                            2-300 Hz). Phase jitter impacts
                                            voiceband data performance and can
                                            make modems more susceptible to
                                            other impairments, including noise.

                                            15.2.5.4.1.11.2 From the NID to the
                                            interexchange carrier point of
                                            termination, phase jitter shall be
                                            (less than) 1.5E point-to-point in
                                            the 0-300 Hz band, and (less than)
                                            1.8E point-to-point in the 4-300 Hz
                                            band.

                                         15.2.5.4.1.12 AMPLITUDE JITTER

                                            15.2.5.4.1.12.1 Amplitude jitter is
                                            any deviation of the peak value of a
                                            1004 Hz signal from its nominal
                                            value. Excessive amounts can impair
                                            voiceband data performance. It is
                                            primarily caused by noise but can
                                            also be caused by phase jitter, gain
                                            hits, or single frequency
                                            interference.

                                            15.2.5.4.1.12.2 In NID-interexchange
                                            carrier point of termination,
                                            (pound) 2.5% of amplitude jitter is
                                            permitted in the 20-300 Hz band and
                                            (pound) 2.9% in the 4-300 Hz band.

                                         15.2.5.4.1.13 INTERMODULATION
                                         DISTORTION

                                            15.2.5.4.1.13.1 Intermodulation
                                            distortion (IMD) measures non-linear
                                            distortions of a signal. It compares
                                            the power of harmonic tones to the
                                            power of the transmitted tones.
                                            It is measured for both the 2nd and
                                            3rd harmonics of the transmitted
                                            tones. IMD is caused by compression
                                            or clipping and can impair voiceband
                                            data performance.

                                            15.2.5.4.1.13.2 Both 2nd and 3rd
                                            order

                                                             Attachment III - 73
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                            IMD between the NID and end office
                                            must be (less than or equal to) 52
                                            dB.

                                         15.2.5.4.1.14 IMPULSE NOISE

                                            15.2.5.4.1.14.1 Impulse noise is a
                                            sudden and large increase in noise
                                            on a channel for a short duration of
                                            time. Impulse noise is measured as a
                                            count of the number of times a noise
                                            threshold is exceeded during a given
                                            time period (typically 5 or 15
                                            minutes). It is caused by protection
                                            switching, maintenance activities,
                                            electromechanical switching systems,
                                            digital transmission errors, and
                                            line coding mismatches. Impulse
                                            noise sounds like clicking noises or
                                            static on voice connections. Impulse
                                            noise impairs voiceband data
                                            performance.

                                            15.2.5.4.1.14.2 The NID to
                                            interexchange carrier point of
                                            termination portions of connections
                                            shall introduce no impulse noise
                                            events within 6 dB of the received
                                            signal power on 93% of all 15 minute
                                            connections. In addition, there
                                            shall be no more than 1 impulse
                                            noise event within 6 dB of the
                                            received signal power during any
                                            30-minute period.

                                         15.2.5.4.1.15 PHASE HITS

                                            15.2.5.4.1.15.1 Phase hits are a
                                            sudden change in the phase of a
                                            signal lasting at least 4 msec.
                                            Phase hits are measured using a
                                            threshold which indicates how much
                                            the phase of the signal has changed
                                            with respect to its nominal phase.
                                            Phase hits are caused by protection
                                            switching and slips or other
                                            synchronization errors. Phase hits
                                            can impair voiceband data
                                            performance.

                                            15.2.5.4.1.15.2 Between the NID and
                                            interexchange carrier point of
                                            termination,

                                                             Attachment III - 74
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                            99.75% of all 15-minute connections
                                            shall have no phase hits exceeding
                                            10E. In addition, there shall be
                                            no more than 1 phase hit exceeding
                                            10E in any 30-minute period.

                                         15.2.5.4.1.16 GAIN HITS

                                            15.2.5.4.1.16.1 Gain hits are sudden
                                            changes in the level of a signal
                                            that last at least 4 msec. Gain hits
                                            are measured against a threshold of
                                            typically 2-5 dB relative to the
                                            signal's nominal level. Gain hits
                                            are usually caused by protection
                                            switches and can impair voiceband
                                            data performance.

                                            15.2.5.4.1.16.2 Between the NID and
                                            the interexchange carrier point of
                                            termination, 99.5% of all 15-minute
                                            connections shall have no gain hits
                                            exceeding 3 dB. In addition, there
                                            shall be no more than 1 gain hit
                                            exceeding 3 dB in any 30-minute
                                            period.

                                         15.2.5.4.1.17 DROPOUTS

                                            15.2.5.4.1.17.1 Dropouts are drops
                                            in the level of a signal of 12 dB or
                                            more for at least 4 msec. They are
                                            caused by protection switching
                                            events, radio fading, and conditions
                                            causing digital carrier systems to
                                            lose frame. Dropouts are critical
                                            for voiceband data performance
                                            but, if severe enough, will also
                                            affect voice quality.

                                            15.2.5.4.1.17.2 Between the NID and
                                            the interexchange carrier point of
                                            termination, 99.9% of all 15-minute
                                            connections shall have no dropouts
                                            and in addition, no connection
                                            shall suffer more than 1 dropout in
                                            any 60-minute period.

                                         15.2.5.4.1.18 FREQUENCY SHIFT

                                                             Attachment III - 75
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              MCIm-BellSouth Mississippi Interconnection Agreement

                                            15.2.5.4.1.18.1 Frequency shift
                                            measures any frequency changes that
                                            occur when a signal is transmitted
                                            across a channel. It is typically
                                            measured using a 1004 Hz tone.
                                            Frequency shift has very little
                                            impact on voice or voiceband data
                                            performance; however, round-trip
                                            frequency shifts can affect the
                                            ability of echo cancelers to remain
                                            converged.

                                            15.2.5.4.1.18.2 No more than 0.2 Hz
                                            frequency shift shall be on any
                                            connection. In addition, 99.5% of
                                            all calls shall have frequency
                                            shift (less than) 0.1 Hz.

                                         15.2.5.4.1.19 CROSSTALK

                                            15.2.5.4.1.19.1 Crosstalk is the
                                            presence of signals from other
                                            telephone connections on a circuit.
                                            Crosstalk can be either
                                            intelligible, when speech from other
                                            connections can be heard and
                                            understood, or unintelligible.
                                            Crosstalk is caused by inter-channel
                                            interference on the transmission
                                            system. Crosstalk is difficult to
                                            measure: it requires correlating
                                            signals on different circuits or
                                            using human listeners to identify
                                            its presence. Trouble reports may be
                                            used to estimate the probability of
                                            crosstalk.

                                            15.2.5.4.1.19.2 99% of Loop
                                            Combinations shall have probability
                                            (pound) 0.1% of experiencing
                                            crosstalk exceeding -65 dBm0.

                                         15.2.5.4.1.20 CLIPPING

                                            15.2.5.4.1.20.1 Clipping occurs when
                                            part of a transmitted signal is
                                            dropped and does not reach the
                                            receiving portion on a connection.
                                            It can be caused by Digital Speech
                                            Interpolation (DSI) equipment used
                                            in Digital Circuit Multiplication
                                            Systems (DCMS) which increase the
                                            amount of

                                                             Attachment III - 76
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              MCIm-BellSouth Mississippi Interconnection Agreement

                                            Traffic that transmission facilities
                                            carry, and by echo cancelers or echo
                                            suppressers.

                                            15.2.5.4.1.20.2 No clipping
                                            incidents shall occur on any call.

                                    15.2.5.4.2 DIGITAL IMPAIRMENTS

                                    Digital impairments occur in the signal
                                    wherever it is transmitted in digital
                                    format. These errors are usually introduced
                                    upon conversion of the signal from analog to
                                    digital, as well as at interfaces between
                                    digital components. While many digital
                                    impairments have little impact on subjective
                                    voice quality, they can impact voiceband
                                    data performance.

                                         15.2.5.4.2.1 SIGNAL CORRELATED
                                         DISTORTION

                                            15.2.5.4.2.1.1 Signal correlated
                                            distortion (SCD) is unwanted noise
                                            or distortion introduced into a
                                            signal through the conversion of a
                                            signal from analog to digital format
                                            or through digital processing that
                                            changes the transmitted signal. SCD
                                            affects performance when a sign is
                                            being transmitted. The primary
                                            sources of SCD are signal encoders,
                                            echo cancelers, digital loss pads,
                                            and robbed bit signaling. SCD
                                            affects both voice and voiceband
                                            data performance.

                                            15.2.5.4.2.1.2 The NID-to-end-office
                                            connection shall allow:

                                            15.2.5.4.2.1.2.1 A maximum of 1 A/D
                                            conversion, using 64 Kbps mlaw
                                            (m255) PCM;

                                            15.2.5.4.2.1.2.2 No voice
                                            compression;

                                            15.2.5.4.2.1.2.3 No echo
                                            cancellation; and

                                            15.2.5.4.2.1.2.4 Robbed bit
                                            signaling only if SS7 or ISDN are
                                            not used.

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              MCIm-BellSouth Mississippi Interconnection Agreement

                                         15.2.5.4.2.2 SLIPS

                                            15.2.5.4.2.2.1 Slips occur when a
                                            frame of digital data is either
                                            deleted or repeated because of
                                            differences in the clocks used to
                                            synchronize digital facilities.
                                            Slips sound like clicks or pops on
                                            voice calls and have major impact on
                                            voiceband data performance.

                                            15.2.5.4.2.2.2 The
                                            NID-to-interexchange carrier point
                                            of termination portion of
                                            connections shall have fewer than
                                            0.45 slips every 24 hours on
                                            average.

                                         15.2.5.4.2.3 DIGITAL TIMING JITTER AND
                                         WANDER

                                            15.2.5.4.2.3.1 Digital timing jitter
                                            is the unwanted phase modulation
                                            of digital signals at rates above 10
                                            Hz. Wander is the unwanted phase
                                            modulation of digital signals at
                                            rates below 10 Hz. Digital timing
                                            jitter is caused by imperfections in
                                            the timing recovery process of
                                            repeaters and the stuffing
                                            synchronization process used by
                                            multiplexer/demultiplexers. Wander
                                            is caused by slowly varying changes
                                            in digital signal phase due to clock
                                            frequency offset and drift, changes
                                            in propagation delay of terrestrial
                                            facilities due to temperature
                                            changes and changes in the distance
                                            of satellites from the earth. These
                                            events have a major impact on
                                            voiceband data performance.

                                            15.2.5.4.2.3.2 The maximum digital
                                            timing jitter allowed in the 10 Hz
                                            to 8 kHz frequency band at any
                                            network interface or any terminal
                                            equipment in the network is 5 Unit
                                            Intervals (UI). The maximum digital
                                            timing jitter allowed in the 8 kHz
                                            to 40 kHz frequency band is 0.1 UI.
                                            The objective for wander is less
                                            than 28 UI at any network interface
                                            or terminal equipment.

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              MCIm-BellSouth Mississippi Interconnection Agreement

                                         15.2.5.4.2.4 DS-1 ERRORED SECONDS

                                            15.2.5.4.2.4.1 An Errored Second
                                            (ES) on a DS-1 facility is any
                                            second during which at least 1 bit
                                            is in error. The impact of an ES on
                                            performance depends on the number of
                                            errors that occur during a second.
                                            Typically, voice performance is not
                                            significantly impacted by ES but
                                            they can cause errors in voiceband
                                            data transmissions.

                                            15.2.5.4.2.4.2 Each BellSouth
                                            network shall have less than 20 ESs
                                            per 24 hour period.

                                         15.2.5.4.2.5 DS-1 SEVERELY ERRORED
                                         SECONDS

                                            15.2.5.4.2.5.1 A severely Errored
                                            Second (SES) is any second during
                                            which a DS-1 has an error rate
                                            exceeding 0.001. An SES can be
                                            caused by a loss of framing, a
                                            slip, or a protection switch. SESs
                                            have impacts on both voice and
                                            voiceband data performance. For
                                            voice, a SES will sound like a burst
                                            of noise or static. SESs that occur
                                            during a voiceband data transmission
                                            cause a significant burst of errors
                                            and can cause modems to retrain.

                                            15.2.5.4.2.5.2 The digital portion
                                            of each NID to POP connection shall
                                            have less than 2 SESs per 24 hour
                                            period.

                                         15.2.5.4.2.6 SHORT FAILURE EVENTS

                                            15.2.5.4.2.6.1 A Short Failure Event
                                            (SFE) is a Loss of Frame (LOF) event
                                            of less than two minutes' duration.
                                            An LOF event is declared when, on
                                            detection of a Loss of Signal (LOS)
                                            or Out-of-Frame (OOF), a
                                            rise-slope-type integration process
                                            starts that declares a LOF after
                                            2.5"0.5 sec. of continuous LOS or
                                            OOF. If the LOS or OOF is
                                            intermittent the integration process

                                                             Attachment III - 79
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              MCIm-BellSouth Mississippi Interconnection Agreement

                                            shall decay at a slope of 1/5 the
                                            rise slope during the period when
                                            the signal is normal. Thus, if the
                                            ratio of a LOS or OOF to a normal
                                            signal is greater than 1/2, a LOF
                                            will be declared. A LOS condition
                                            shall be declared when the Network
                                            Channel Terminating Equipment has
                                            determined that 175"75 successive
                                            pulse positions with no pulses of
                                            either positive or negative polarity
                                            have occurred. An OOF condition
                                            shall be declared when either
                                            Network equipment or Digital
                                            Terminal Equipment detects errors in
                                            the framing pattern.

                                            15.2.5.4.2.6.2 There shall be fewer
                                            than 1 SFE per month.

                           15.2.5.5 SERVICE AVAILABILITY AND RELIABILITY

                           Availability refers to the time period during which
                           the service is up and usable for its intended
                           purpose. Reliability refers to the probability that a
                           task will be completed successfully, given that it is
                           successfully begun.

                                    15.2.5.5.1 BLOCKED CALLS

                                         15.2.5.5.1.1 Blocking is the fraction
                                         of call origination attempts denied
                                         service during a stated measurement
                                         period. Blocking occurs because of
                                         competition for limited resources
                                         within the network.

                                         15.2.5.5.1.2 For intraLATA toll
                                         service and local exchange service,
                                         the blocking level from originating
                                         (NID) to terminating NID shall not
                                         exceed 1% in any hour, except under
                                         conditions of service disruption.
                                         For access to or egress from a long
                                         distance network, the blocking rate
                                         shall not exceed 0.5% in any hour.

                                    15.2.5.5.2 DOWNTIME

                                    Downtime is the period of time that a system
                                    is in a failed state.

                                                             Attachment III - 80
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              MCIm-BellSouth Mississippi Interconnection Agreement

                                         15.2.5.5.2.1 The average downtime for
                                         all subscriber Loop Combinations shall
                                         be less than 49 minutes per year. The
                                         maximum downtime for 99% of all
                                         subscriber Loop Combinations shall be
                                         less than 74 minutes per year.

                                         15.2.5.5.2.2 The average downtime for
                                         an end office switch shall be less than
                                         3 minutes per year. The average
                                         downtime for individual trunks shall be
                                         less than 28 minutes per year. The
                                         average downtime for digital trunk
                                         groups shall be less than 20 minutes
                                         per year. The average downtime for an
                                         individual line appearance at the
                                         switch shall be less than 28 minutes
                                         per year. The average downtime for a
                                         Remote Terminal (RT) shall be less than
                                         17 minutes per year. The average
                                         downtime for an individual line on a
                                         Remote Terminal (RT) shall be less than
                                         13 minutes per year.

                                         15.2.5.5.2.3 The mean time to repair
                                         (MTTR) of any equipment at an attended
                                         site shall be less than 3 hours. The
                                         mean time to repair (MTTR) of any
                                         equipment at an unattended site shall
                                         be less than 4 hours. 95% of all
                                         repairs to the network interface (NID)
                                         shall be completed within 24 hours.

                                         15.2.5.5.2.4 There shall be no downtime
                                         due to power failures at the switch.

                                         15.2.5.5.2.5 The probability of a
                                         stable call being cut off shall be
                                         less than 20 cutoffs per one million
                                         1 minute calls.

                                         15.2.5.5.2.6 The rate of ineffective
                                         machine attempts at the end office
                                         shall be less than 0.0005 (5 failures
                                         per 10,000 call attempts).

                                         15.2.5.5.2.7 BellSouth shall meet all
                                         requirements for private line services
                                         in TR-NWT-000335, ANSI T1.512-1994.

                                    15.2.5.5.3 DIAL TONE DELAY

                                                             Attachment III - 81
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         15.2.5.5.3.1 Dial-Tone Delay is the
                                         time period between a subscriber
                                         off-hook and the receipt of dial tone
                                         from an originating end office.
                                         Dial-Tone Delay has a significant
                                         effect on subscriber opinion of service
                                         quality.

                                         15.2.5.5.3.2 The average dial-tone
                                         delay shall not exceed 1.5% of calls
                                         delayed more than 3 seconds. At most
                                         20% of calls during the high day busy
                                         hour (HDBH) shall experience dial-tone
                                         delay greater than 3 seconds.

                                    15.2.5.5.4 DIAL TONE REMOVAL

                                         15.2.5.5.4.1 Dial tone removal is the
                                         time between recognition of the first
                                         address digit to the removal of dial
                                         tone on the line.

                                         15.2.5.5.4.2 The maximum dial tone
                                         removal interval shall be (pound)500
                                         milliseconds.

                                    15.2.5.5.5 POST DIAL DELAY

                                         15.2.5.5.5.1 Post Dial Delay (PDD)
                                         is the amount of time a caller must
                                         wait after entering or dialing the
                                         last digit of a Destination
                                         Telephone Number (DTN) before
                                         hearing a valid audible network
                                         response. The PDD for an end user is
                                         measured from the time the caller
                                         has pressed or dialed the last digit
                                         of a DTN until receipt of an audible
                                         network response.

                                         15.2.5.5.5.2 The requirements given
                                         reflect an end-to-end CCS7 protocol
                                         for MCIm end users. Where a mixture
                                         of CCS7 and inband (MF) signaling
                                         protocols are employed, an increase
                                         in the PDD can be expected.

                                            15.2.5.5.5.2.1 PDD 1 - A - INTRA LSO

                                            15.2.5.5.5.2.1.1 Intra-LSO calls do
                                            not employ external signaling
                                            protocols. The PDD for intra-LSO
                                            calls flows are dependent upon the
                                            processor cycle time

                                                             Attachment III - 82
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                            and traffic load conditions. This
                                            PDD is assumed to be between
                                            subscribers on the same LSO, between
                                            the Remote Switch Modules (RSMs) on
                                            the same Host, or between an RSM and
                                            Host subscribers.

                                            15.2.5.5.5.2.1.2 The objective for
                                            intra-LSO PDD is less than 310
                                            milliseconds for 50% of all calls
                                            and less than 460 milliseconds for
                                            95% of all calls.

                                            15.2.5.5.5.2.2 PDD1 - B - LSO TO
                                            ANOTHER LOCAL LSO

                                            15.2.5.5.5.2.2.1 The signaling
                                            protocols from an LSO to another LSO
                                            are assumed to employ out-of-band
                                            Common Channel Signaling System 7
                                            (CCS7) format. Local calls, that
                                            is, calls from an LSO to another
                                            LSOs are assumed to have no more
                                            than one pair of Signaling Transfer
                                            Point Switches (STPs) and no more
                                            than one data base dip.

                                            15.2.5.5.5.2.2.2 This PDD is
                                            expected to be better than the MCIT
                                            Long Distance objective with an
                                            average PDD of (pound) 8.70 seconds
                                            with 95% (pound)1.34 seconds.

                                            15.2.5.5.5.2.3 PDD1 - C - MCIM LSO
                                            TO OTHER LSO

                                            15.2.5.5.5.2.3.1 Calls from an MCIm
                                            LSO to other LSOs are dependent upon
                                            the interface agreements between
                                            MCIm and the LSO service provider
                                            and may employ CCS7, inband (MF) or
                                            a combination of both protocols.

                                            15.2.5.5.5.2.3.2 Calls from an MCIm
                                            LSO to another LSO via the Public
                                            Switched Telecommunications
                                            Network (PSTN), using end-to-end
                                            CCS7 signaling protocols, can
                                            expect to meet the MCIm PDD
                                            objectives of an average of 2.0
                                            seconds

                                                             Attachment III - 83
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                            with 95% in (less than) 2.5 seconds.
                                            Calls from an MCIm LSO via the PSTN
                                            to LSOs outside the local service
                                            area are assumed to use CCS7
                                            signaling protocols to the MCIm
                                            switch. The egress signaling
                                            protocols from the MCIT Switched
                                            Network to the many different local
                                            telephone company service providers
                                            however does not necessarily utilize
                                            CCS7 signaling. There are three
                                            basic egress signaling
                                            configuration. They are:

                                            15.2.5.5.5.2.3.2.1 Network
                                            Inter-Connect, CCS7 between MCIm
                                            and the local telephone company.

                                            15.2.5.5.5.2.3.2.2 Inband
                                            Multifrequency (MF) signaling
                                            protocols without a BellSouth egress
                                            tandem in the connection.

                                            15.2.5.5.5.2.3.2.3 Inband MF
                                            signaling protocols with a BellSouth
                                            egress tandem in the connection.

                                            15.2.5.5.5.2.3.2.3.1 Calls from an
                                            MCIm LSO to other LSOs outside the
                                            local service area are assumed to
                                            have multiple STPs for 1+ traffic in
                                            the access and PSTN portion of the
                                            connection. The egress from the PSTN
                                            for 1+ traffic is again dependent
                                            upon the interface agreements in
                                            that service area and may consist of
                                            CCS7 or inband MF protocols.

                                            15.2.5.5.5.2.3.2.3.2 Calls from an
                                            MCIm's LSO to another MCIm LSO with
                                            a mixture of CCS7 or all inband
                                            signaling protocols are expected to
                                            receive PDDs on the average of 2.9
                                            seconds with 95% in less than or
                                            equal to 6.5 seconds.

                                            15.2.5.5.5.2.4 IMPACT OF NUMBER
                                            PORTABILITY (NP)

                                            If a call forwarding option is used
                                            as an

                                                             Attachment III - 84
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              MCIm-BellSouth Mississippi Interconnection Agreement

                                            Interim solution for NP, the delay
                                            due to additional switching in the
                                            local access shall not exceed 0.4
                                            seconds when MCIm is direct
                                            connected to the BellSouth end
                                            office, and 0.8 seconds when MCIm is
                                            connected to the BellSouth tandem,
                                            in addition to the PDDs described
                                            above.

                                            15.2.5.5.5.2.5 CUSTOM LOCAL AREA
                                            SUBSCRIBER SERVICES (CLASS)

                                            CLASS SM features such as Calling
                                            Name Delivery can contribute to the
                                            PDD of a call. This delay is caused
                                            by the additional time (BellSouth
                                            option) before the ringing interval
                                            commences. This default delay is 3
                                            seconds. Optional settings are
                                            available in 1 second intervals from
                                            1 to 6 seconds. Calls to DTNs that
                                            have CLASS SM features, particularly
                                            with calling name delivery, can
                                            expect to experience from 1 to 6
                                            seconds (3 seconds default) of
                                            additional PDD compared to the PDDs
                                            shown for PDD1-C. MCI will specify
                                            optimal settings.

                                            15.2.5.5.5.2.6 PARTIAL DIAL TIMING

                                            15.2.5.5.5.2.6.1 The interval
                                            between each information digit from
                                            a subscriber's line, until the LSO
                                            or switching system has determined
                                            that the digit string is incomplete.

                                            15.2.5.5.5.2.6.2 For subscriber
                                            lines, partial dial timing shall be
                                            (more than or equal to) 16 seconds
                                            and more than 24 seconds. For
                                            trunks, inband signaling time-out
                                            shall be (3)5 seconds and (less than
                                            or equal to) 20 seconds.

                           15.2.5.6 LOCAL SWITCHING

                           BellSouth shall provide performance equal to or
                           better than the requirements for Local Switching set
                           forth in Bellcore LSSGR TR-TSY-000511. Post dial
                           delay for connections to MCIm local operator services
                           shall be no worse than Operator Services

                                                             Attachment III - 85
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           provided by BellSouth. Additionally, post dial delay
                           from the Operator Services to destination numbers
                           shall be no worse than that provided by BellSouth.
                           Post dial delay for connections to MCIm local
                           directory services shall be no worse than directory
                           services provided by BellSouth. Additionally, post
                           dial delay from the directory system to destination
                           numbers shall be no worse than that provided by
                           BellSouth.

                           15.2.5.7 OPERATOR SYSTEMS

                           Operator System connections shall comply with the
                           requirements for the Loop Combination, Local
                           Switching, Operator Service, and Directory Assistance
                           Service requirements.

                           15.2.5.8 COMMON TRANSPORT

                           Specific requirements for this Network Element or
                           Ancillary Function are in the Common Transport
                           section. In all cases the performance of this Network
                           Element shall meet the general requirements stated in
                           "General Performance Requirements." Allocation of
                           impairments shall be negotiated between MCIm and
                           BellSouth consistent with sound engineering
                           principles.

                           15.2.5.9 DEDICATED TRANSPORT

                           Specific requirements for this Network Element are in
                           the Dedicated Transport section. In all cases the
                           performance of this Network Element shall meet the
                           general requirements stated in "General Performance
                           Requirements." (Allocation of impairments shall be
                           negotiated between MCIm and BellSouth consistent with
                           sound engineering principles.)

                           15.2.5.10 SIGNALING TRANSFER POINTS

                           Specific requirements for this Network Element are in
                           the Signaling Transfer Points section. In all cases
                           the performance of this Network Element shall meet
                           the general requirements stated in "General
                           Performance Requirements." (Allocation of impairments
                           shall be negotiated between MCIm and BellSouth.)

                           15.2.5.11 SIGNALING LINK TRANSPORT

                           Specific requirements for this Network Element are in
                           the Signaling Link Transport section. In all cases
                           the performance of this Network Element shall meet
                           the general requirements

                                                             Attachment III - 86
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           stated in "General Performance Requirements."
                           Allocation of impairments shall be negotiated between
                           MCIm and BellSouth consistent with sound engineering
                           principles.

                           15.2.5.12 SCPS/DATABASES

                           The performance requirements for databases (NP, LIDB,
                           E911, etc.) vary depending or the database and the
                           applications it supports. Database-specific
                           performance requirements are included in the sections
                           addressing individual Network Elements and in
                           applicable Bellcore documents. In all cases, the
                           query response time, availability, accuracy, updating
                           capabilities, and other performance parameters shall
                           at least be at parity with those services as provided
                           to BellSouth or other subscriber.

                           15.2.5.13 TANDEM SWITCHING

                           Specific requirements for this Network Element are in
                           the Tandem Switching section. In all cases the
                           performance of this Network Element shall meet the
                           general requirements stated in "General Performance
                           Requirements." Allocation of impairments shall be
                           negotiated between MCIm and BellSouth consistent with
                           sound engineering principles.

                                    15.2.6 TEST AND VERIFICATION

                                    15.2.6.1 BellSouth shall permit MCIm to
                                    confirm acceptable performance of any
                                    Network Element.

                                    15.2.6.1.1 At MCIm's request, BellSouth
                                    will provide access to the Network Element
                                    sufficient for MCIm to test the performance
                                    of that Network Element to MCIm's
                                    satisfaction.

                                    15.2.6.1.2 At MCIm's request, BellSouth
                                    will perform tests to confirm acceptable
                                    performance and provide MCIm with
                                    documentation of test procedures and results
                                    acceptable to MCIm.

         15.3 PROTECTION, RESTORATION, AND DISASTER RECOVERY

                  15.3.1   SCOPE:

                  This Section refers specifically to requirements on the use of

                                                             Attachment III - 87
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  redundant network equipment and facilities for protection,
                  restoration, and disaster recovery.

                  15.3.2   REQUIREMENTS

                           15.3.2.1 BellSouth shall provide protection,
                           restoration, and disaster recovery capabilities at
                           parity with those capabilities provided for their own
                           services, facilities and equipment (e.g., equivalent
                           circuit pack protection ratios, facility protection
                           ratios).

                           15.3.2.2 BellSouth shall provide Network Elements and
                           Ancillary Functions equal priority in protection,
                           restoration, and disaster recovery as provided to
                           their own services, facilities and equipment.

                           15.3.2.3 BellSouth shall provide Network Elements and
                           Ancillary Functions equal priority in the use of
                           spare equipment and facilities as provided to their
                           own services, facilities and equipment.

                           15.3.2.4 BellSouth shall restore Network Elements
                           which are specific to MCIm end user subscribers on a
                           priority basis as MCIm may designate.

         15.4 SYNCHRONIZATION

                  15.4.1   DEFINITION

                  Synchronization is the function which keeps all digital
                  equipment in a communications network operating at the same
                  average frequency. With respect to digital transmission,
                  information is coded into discrete pulses. When these pulses
                  are transmitted through a digital communications network, all
                  synchronous Network Elements are traceable to a stable and
                  accurate timing source. Network synchronization is
                  accomplished by timing all synchronous Network Elements in the
                  network to a stratum 1 source so that transmission from these
                  network points have the same average line rate.

                  15.4.2   TECHNICAL REQUIREMENTS

                  The following requirements are applicable to the case where
                  Bell South provides synchronization to equipment that MCIm
                  owns and operates

                                                             Attachment III - 88
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  within a BellSouth location. In addition, these requirements
                  apply to synchronous equipment that is owned by BellSouth and
                  is used to provide a Network Element to MCIm.

                           15.4.2.1 The synchronization of clocks within digital
                           networks is divided into two parts: intra-building
                           and inter-building. Within a building, a single clock
                           is designated as the Building Integrated Timing
                           Supply (BITS), which provides all of the DS1 and DS0
                           synchronization references required by other clocks
                           in such building. This is referred to as
                           intra-building synchronization. The BITS receives
                           synchronization references from remotely located
                           BITS. Synchronization of BITS between buildings is
                           referred to as inter-building synchronization.

                           15.4.2.2 To implement a network synchronization plan,
                           clocks within digital networks are divided into four
                           stratum levels. All clocks in strata 2, 3, and 4 are
                           synchronized to a stratum 1 clock, that is, they are
                           traceable to a stratum 1 clock. A traceable reference
                           is a reference that can be traced back through some
                           number of clocks to a stratum 1 source. Clocks in
                           different strata are distinguished by their free
                           running accuracy or by their stability during trouble
                           conditions such as the loss of all synchronization
                           references.

                                    15.4.2.2.1 INTRA-BUILDING

                                         15.4.2.2.1.1 Within a building, there
                                         may be different kinds of equipment
                                         that require synchronization at the DS1
                                         and DS0 rates. Synchronization at the
                                         DS1 rate is accomplished by the
                                         frequency synchronizing presence of
                                         buffer stores at various DSl
                                         transmission interfaces.
                                         Synchronization at the DS0 rate is
                                         accomplished by using a composite
                                         clock signal that phase synchronizes
                                         the clocks. Equipment requiring DS0
                                         synchronization frequently does not
                                         have adequate buffer storage to
                                         accommodate the phase variations
                                         among different equipment. Control
                                         of phase variations to an acceptable
                                         level is accomplished by externally
                                         timing all interconnecting DS0 circuits
                                         to a single clock source and by
                                         limiting the interconnection of DS0
                                         equipment to less than 1,500 cable
                                         feet. Therefore, a BITS shall provide
                                         DS1 and composite clock signals when
                                         the appropriate

                                                             Attachment III - 89
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              MCIm-BellSouth Mississippi Interconnection Agreement

                                         composite signal is a 64-kHz 5/8th
                                         duty cycle, return to zero with a
                                         bipolar violation every eighth pulse
                                         (B8RZ).

                                    15.4.2.2.2 INTER-BUILDING

                                         15.4.2.2.2.1 BellSouth shall provide
                                         inter-building synchronization at the
                                         DSl rate, and the BITS shall accept the
                                         primary and secondary synchronization
                                         links from BITS in other buildings.
                                         From hierarchical considerations, the
                                         BITS shall be the highest stratum clock
                                         within the building and BellSouth shall
                                         provide operations capabilities (this
                                         includes, but is not limited to:
                                         synchronization reference provisioning;
                                         synchronization reference status
                                         inquiries; timing mode status
                                         inquiries; and alarm conditions).

                  15.4.3   SYNCHRONIZATION DISTRIBUTION REQUIREMENTS

                           15.4.3.1 Central office BITS shall contain redundant
                           clocks meeting or exceeding the requirements for a
                           stratum 2 clock as specified in ANSI T1.101-1994 and
                           Bellcore TR-NWT-001244 Clocks for the Synchronized
                           Network: Common Genetic Criteria.

                           15.4.3.2 Central office BITS shall be powered by
                           primary and backup power sources.

                           15.4.3.3 If both reference inputs to the BITS are
                           interrupted or in a degraded mode (meaning off
                           frequency greater than twice the minimum accuracy of
                           the BITS, loss of frame, excessive bit errors, or in
                           Alarm Indication Signal), then the stratum clock in
                           the BITS shall provide the necessary bridge in timing
                           to allow the network to operate without a frame
                           repetition or deletion (slip free) with better
                           performance than 1 frame repetition or deletion
                           (slip) per week.

                           15.4.3.4 DS1s multiplexed into a SONET synchronous
                           payload envelope within an STS-n (where n is defined
                           in ANSI T1.105-1995) signal shall not be used as
                           reference facilities for network synchronization.

                           15.4.3.5 The total number of Network Elements
                           cascaded from the stratum 1 source shall be
                           minimized.

                                                             Attachment III - 90
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              MCIm-BellSouth Mississippi Interconnection Agreement

                           15.4.3.6 A Network Element shall receive the
                           synchronization reference signal only from another
                           Network Element that contains a clock of equivalent
                           or superior quality (stratum level).

                           15.4.3.7 BellSouth shall select for synchronization
                           those facilities shown to have the greatest degree of
                           availability (absence of outages).

                           15.4.3.8 Where possible, all primary and secondary
                           synchronization facilities shall be physically
                           diverse (this means the maximum feasible physical
                           separation of synchronization equipment and cabling).

                           15.4.3.9 No timing loops shall be formed in any
                           combination of primary and secondary facilities.

                           15.4.3.10 An Operations Support System (OSS) shall
                           continuously monitor the BITS for synchronization
                           related failures or degradation.

                           15.4.3.11 An OSS shall continuously monitor all
                           equipment transporting synchronization facilities for
                           synchronization related failures or degradation.

                           15.4.3.12 For non-SONET equipment, BellSouth shall
                           provide synchronization facilities which, at a
                           minimum, comply with the standards set forth in ANSI
                           T1.101-1994.

                           15.4.3.13 For SONET equipment, BellSouth shall
                           provide synchronization facilities that have time
                           deviation (TDEV) for integration times greater than
                           0.05 seconds and less than or equal to 10 seconds,
                           that is less than or equal to 10 nanoseconds. TDEV,
                           in nanoseconds, for integration times greater than 10
                           seconds and less than 1000 seconds, shall be less
                           than 3.1623 times the square-root of the integration
                           time. For example, for integration times of 25
                           seconds, TDEV shall be less than 15.8 nanoseconds.

         15.5 SS7 NETWORK INTERCONNECTION

                  15.5.1   DEFINITION

                  Figure 8 depicts Signaling System 7 (SS7) Network
                  Inter-connection. SS7 Network Interconnection is the
                  interconnection of MCIm local

                                                             Attachment III - 91
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              MCIm-BellSouth Mississippi Interconnection Agreement

                  Signaling Transfer Point (STPs) with BellSouth STPs. This
                  interconnection provides connectivity that enables the
                  exchange of SS7 messages among BellSouth switching systems and
                  databases (DBs), MCIm local or tandem switching systems, and
                  other third-party switching systems directly connected to the
                  BellSouth SS7 network.

                               [GRAPHIC OMITTED]

                     FIGURE 8. SS7 NETWORK INTERCONNECTION

                  15.5.2 TECHNICAL REQUIREMENTS

                           15.5.2.1 SS7 Network Interconnection shall provide
                           connectivity to all components of the BellSouth SS7
                           network. These include:

                                    15.5.2.1.1 BellSouth local or tandem
                                    switching systems;

                                    15.5.2.1.2 BellSouth DBs; and

                                    15.5.2.1.3 Other third-party local or tandem
                                    switching systems.

                           15.5.2.2 The connectivity provided by SS7 Network
                           Interconnection shall fully support the functions of
                           BellSouth switching systems and DBs and MCIm or other
                           third-party switching systems with A-link access to
                           the BellSouth SS7 network.

                                                             Attachment III - 92
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           15.5.2.3 In particular, Figure 9 depicts a
                           circumstance where SS7 Network Interconnection shall
                           provide transport for certain types of Transaction
                           Capabilities Application Part (TCAP) messages. If
                           traffic is routed based on dialed or translated
                           digits between an MCIm local switching system and a
                           BellSouth or other third-party local switching
                           system, either directly or via a BellSouth tandem
                           switching system, then it is a requirement that the
                           BellSouth SS7 network convey via SS7 Network
                           Interconnection the TCAP messages that are necessary
                           to provide Call Management services (Automatic
                           Callback, Automatic Recall, and Screening List
                           Editing) between the MCIm local STPs and the
                           BellSouth or other third-party local switch

                               [GRAPHIC OMITTED]

      FIGURE 9. INTERSWITCH TCAP SIGNALING FOR SS7 NETWORK INTERCONNECTION

                           15.5.2.4 When the capability to route messages based
                           on Intermediate Signaling Network Identifier (ISNI)
                           is generally available on BellSouth STPs, the
                           BellSouth SS7 Network shall also convey TCAP messages
                           using SS7 Network Interconnection in similar
                           circumstances where the BellSouth switch routes
                           traffic based on a Carrier Identification Code (CIC).

                           15.5.2.5 SS7 Network Interconnection shall provide
                           all

                                                             Attachment III - 93
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           functions of the MTP as specified in ANSI T1. 111
                           (Reference 12.5.2). This includes:

                                    15.5.2.5.1 Signaling Data Link functions, as
                                    specified in ANSI T1.111.2;

                                    15.5.2.5.2 Signaling Link functions, as
                                    specified in ANSI T1.111.3; and

                                    15.5.2.5.3 Signaling Network Management
                                    functions, as specified in ANSI T1.111.4.

                           15.5.2.6 SS7 Network Interconnection shall provide
                           all functions of the SCCP necessary for Class 0
                           (basic connectionless) service, as specified in ANSI
                           T1.112 (Reference 12.5.4). In particular, this
                           includes Global Title Translation (GTT) and SCCP
                           Management procedures, as specified in T1.112.4.

                           15.5.2.7 Where the destination signaling point is a
                           BellSouth switching system or DB, or is another
                           third-party local or tandem switching system directly
                           connected to the BellSouth SS7 network, SS7 Network
                           Interconnection shall include final GTT of messages
                           to the destination and SCCP Subsystem Management of
                           the destination.

                           15.5.2.8 Where the destination signaling point is an
                           MCIm local or tandem switching system, SS7 Network
                           Interconnection shall include intermediate GTT of
                           messages to a gateway pair of MCIm local STPs, and
                           shall not include SCCP Subsystem Management of the
                           destination.

                           15.5.2.9 SS7 Network Interconnection shall provide
                           all functions of the Integrated Services Digital
                           Network User Part (ISDNUP), as specified in ANSI
                           T1.113.

                           15.5.2.10 SS7 Network Interconnection shall provide
                           all functions of the TCAP, as specified in ANSI
                           T1.114.

                           15.5.2.11 If and when Internetwork MTP Routing
                           Verification Test (MRVT) and SCCP Routing
                           Verification Test (SRVT) become approved ANSI
                           standards and available capabilities of BellSouth
                           STPs, SS7 Network Interconnection shall provide these
                           functions of the OMAP.

                                                             Attachment III - 94
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           15.5.2.12 SS7 Network Interconnection shall be equal
                           to or better than the following performance
                           requirements:

                                    15.5.2.12.1 MTP Performance, as specified in
                                    ANSI T1.111.6;

                                    15.5.2.12.2 SCCP Performance, as specified
                                    in ANSI T1.112.5; and

                                    15.5.2.12.3 ISDNUP Performance, as specified
                                    in ANSI T1.113.5.

                  15.5.3   INTERFACE REQUIREMENTS

                           15.5.3.1 BellSouth shall offer the following SS7
                           Network Interconnection options to connect MCIm or
                           MCIm-designated STPs to the BellSouth SS7 network:

                                    15.5.3.1.1 D-link interface from MCIm STPs.

                           15.5.3.2 Each interface shall be provided by one or
                           more sets (layers) of signaling links, as depicted in
                           Figure 10:

                               [GRAPHIC OMITTED]

                          FIGURE 10. D-LINK INTERFACE

                           15.5.3.3 The Signaling Point of Interconnection
                           (SPOI) for each link shall be located at a
                           cross-connect element, including but not limited to a
                           DSX-1, in the Central Office (CO) where the BellSouth
                           STPs is located. There shall be a DS1 or higher rate
                           transport interface at each of the SPOIs. Each
                           signaling link shall appear as a DS0 channel within
                           the DS1 or higher rate

                                                             Attachment III - 95
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           interface. BellSouth shall offer higher rate DS1
                           signaling links for interconnecting MCIm local
                           switching systems or STPs with BellSouth STPs as soon
                           as these become approved ANSI standards and available
                           capabilities of BellSouth STPs.

                                    15.5.3.3.1 In each LATA, there will be two
                                    signaling points of interconnection (SPOIs).
                                    The requirement for two SPOIs is driven by
                                    the critical importance attached by all
                                    parties to signaling link diversity.

                                    15.5.3.3.2 Each party will designate one of
                                    the two SPOIs in the LATA. A SPOI can be any
                                    existing cross connect point in the LATA.
                                    Since each party will designate a SPOI, we
                                    believe that both parties will be incented
                                    to select reasonable and efficient SPOI
                                    locations.

                                    15.5.3.3.3 Each signaling link requires a
                                    port on each party's STP, which each party
                                    shall provide without explicit charge.

                           15.5.3.4 The BellSouth CO shall provide intraoffice
                           diversity between the SPOIs and the BellSouth STPs,
                           so that no single failure of intraoffice facilities
                           or equipment shall cause the failure of both D-links
                           in a layer connecting to a BellSouth STPs.

                           15.5.3.5 The protocol interface requirements for SS7
                           Network Interconnection include the MTP, ISDNUP, SCCP
                           and TCAP. These protocol interfaces shall conform to
                           the following specifications:

                                    15.5.3.5.1 Bellcore GR-905-CORE, Common
                                    Channel Signaling Network Interface
                                    Specification (CCSNIS) Supporting Network
                                    Interconnection, Message Transfer Part
                                    (MTP), and Integrated Services Digital
                                    network User Part (ISDNUP);

                                    15.5.3.5.2 Bellcore GR-1428-CORE, CCS
                                    Network Interface Specification (CCSNIS)
                                    Supporting Toll Free Service;

                                    15.5.3.5.3 Bellcore GR-1429-CORE, CCS
                                    Network Interface Specification (CCSNIS)
                                    Supporting Call Management Services; and

                                                             Attachment III - 96
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              MCIm-BellSouth Mississippi Interconnection Agreement

                                    15.5.3.5.4 Bellcore GR-1432-CORE, CCS
                                    Network Interface Specification (CCSNIS)
                                    Supporting Signaling Connection Control Part
                                    (SCCP) and Transaction Capabilities
                                    Application Part (TCAP).

                           15.5.3.6 BellSouth shall set message screening
                           parameters to block accept messages from MCIm local
                           or tandem switching systems destined to any signaling
                           point in the BellSouth SS7 network with which the
                           MCIm switching system has a legitimate signaling
                           relation.

                  15.5.4   SS7 Network Interconnection shall be equal to or
                  better than all of the requirements for SS7 Network
                  Interconnection set forth in the following technical
                  references:

                           15.5.4.1 ANSI T1.110-1992 American National Standard
                           Telecommunications Signaling System Number 7 (SS7) -
                           General Information;

                           15.5.4.2 ANSI T1.111-1992 American National Standard
                           for Telecommunications - Signaling System Number 7
                           (SS7) - Message Transfer Part (MTP);

                           15.5.4.3 ANSI T1.111A-1994 American National Standard
                           for Telecommunications - Signaling System Number 7
                           (SS7) - Message Transfer Part (MTP) Supplement;

                           15.5.4.4 ANSI T1.112-1992 American National Standard
                           for Telecommunications - Signaling System Number 7
                           (SS7) - Signaling Connection Control Part (SCCP);

                           15.5.4.5 ANSI T1.113-1995 American National Standard
                           for Telecommunications - Signaling System Number 7
                           (SS7) - Integrated Services Digital Network (ISDN)
                           User Part;

                           15.5.4.6 ANSI T1.114-1992 American National Standard
                           for Telecommunications - Signaling System Number 7
                           (SS7) - Transaction Capabilities Application Part
                           (TCAP);

                           15.5.4.7 ANSI T1.115-1990 American National Standard
                           for Telecommunications - Signaling System Number 7
                           (SS7) - Monitoring and Measurements for Networks;

                           15.5.4.8 ANSI T1.116-1990 American National Standard
                           for

                                                             Attachment III - 97
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           Telecommunications - Signaling System Number 7 (SS7)
                           - Operations, Maintenance and Administration Part
                           (OMAP);

                           15.5.4.9 ANSI T1.118-1992 American National Standard
                           for Telecommunications - Signaling System Number 7
                           (SS7) - Intermediate Signaling Network Identification
                           (ISNI);

                           15.5.4.10 Bellcore GR-905-CORE, Common Channel
                           Signaling Network Interface Specification (CCSNIS)
                           Supporting Network Interconnection, Message Transfer
                           Part (MTP), and Integrated Services Digital Network
                           User Part (ISDNUP);

                           15.5.4.11 Bellcore GR-954-CORE, CCS Network Interface
                           Specification (CCSNIS) Supporting Line Information
                           Database (LIDB) Service;

                           15.5.4.12 Bellcore GR-1428-CORE, CCS Network
                           Interface Specification (CCSNIS) Supporting Toll Free
                           Service;

                           15.5.4.13 Bellcore GR-1429-CORE, CCS Network
                           Interface Specification (CCSNIS) Supporting Call
                           Management Services; and,

                           15.5.4.14 Bellcore GR-1432-CORE, CCS Network
                           Interface Specification (CCSNIS) Supporting Signaling
                           Connection Control Part (SCCP) and Transaction
                           Capabilities Application Part (TCAP).

         15.6 NETWORK INTERCONNECTION

                  15.6.1   TECHNICAL REQUIREMENTS

                           15.6.1.1 When requested by MCIm, BellSouth shall
                           provide interconnections between the BellSouth
                           Network Elements provided to MCIm and MCIm's network
                           at transmission rates designated by MCIm.

                           15.6.1.2 Traffic shall be combined and routed as
                           follows:

                                    15.6.1.2.1 BellSouth shall provide direct
                                    trunks for intraLATA traffic (except 911,
                                    directory assistance, operator services, and
                                    other services that may require special
                                    routing) and, at MCIm's request, BellSouth
                                    shall allow MCIm to route such traffic
                                    either directly to a BellSouth tandem or
                                    directly to a BellSouth end-office.

                                                             Attachment III - 98
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                    At MCIm's option, intraLATA toll and local
                                    traffic shall be combined onto one trunk
                                    group.

                                    15.6.1.2.2 At MCIm's request, BellSouth
                                    shall receive MCIm traffic destined to the
                                    BellSouth Operator Systems Network Element,
                                    on trunks from an MCIm end-office or an MCIm
                                    tandem.

                                    15.6.1.2.3 At MCIm's request, BellSouth
                                    shall receive MCIm CAMA-ANI (Centralized
                                    Automatic Message Accounting - Automatic
                                    Number identification) traffic destined to
                                    the BellSouth B911 PSAPs, or E911 tandems,
                                    on trunks from an MCIm end-office.

                                    15.6.1.2.4 If and when S911 is being
                                    provided by BellSouth, at MCIm's request,
                                    BellSouth shall receive MCIm SS7 traffic
                                    destined to any BellSouth S911 tandem on
                                    trunks from an MCIm end-office.

                           15.6.1.3 When requested by MCIm and a third party
                           carrier, BellSouth shall provide interconnections
                           between MCIm's network, and the other carrier's
                           network through the BellSouth network at transmission
                           rates designated by MCIm, including, but not limited
                           to DS1, DS3, and STS-1. BellSouth shall combine and
                           route traffic to and from other local carriers and
                           interLATA carriers through the BellSouth network, and
                           at MCIm's request, BellSouth shall record and keep
                           records of such traffic for MCIm billing purposes.

                           15.6.1.4 BellSouth shall provide two-way trunk groups
                           for interconnections. At MCIm's request, BellSouth
                           shall provide unidirectional traffic on such trunks,
                           in either direction, effectively operating them as if
                           they were one-way trunk groups.

                           15.6.1.5 BellSouth shall provision trunks without any
                           user restrictions (e.g., option for two-way trunking
                           where mutually agreed to, and no unnecessary trunk
                           group fragmentation by traffic types; provided that
                           the party receiving the traffic has the right to
                           receive traffic in the manner set forth section 1.1.2
                           of Attachment IV).

                           15.6.1.6 All trunking provided by BellSouth shall
                           adhere to the applicable performance requirements set
                           forth in the "General Performance Requirements"
                           section of this Agreement.

                                                             Attachment III - 99
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                           15.6.1.7 At MCIm's request, BellSouth shall provide
                           for overflow routing from a given trunk group or
                           groups onto another trunk group or groups as MCIm
                           designates.

                           15.6.1.8 BellSouth and MCIm shall agree on the
                           establishment of two-way trunk groups for the
                           exchange of traffic for other IXCs. These trunk
                           groups can be provided in a "meet point" arrangement.

                           15.6.1.9 Interconnection shall be made available upon
                           MCIm's request at any Technically Feasible point of
                           interface. All trunk interconnections shall be
                           provided, including, SS7, MF, DTMF, DialPulse,
                           PRI-ISDN (where available), DID (Direct Inward
                           Dialing), CAMA-ANI, and trunking necessary so that
                           interim NP can be provided.

                           15.6.1.10 TRUNK INTERFACE REQUIREMENTS

                                    15.6.1.10.1 B911/E911 TRUNKS

                                         15.6.1.10.1.1 BellSouth shall allow
                                         MCIm to provide direct trunking to
                                         BellSouth E911 tandem. These trunks
                                         are to be provided as one-way trunks
                                         from a given MCIm end office to the
                                         BellSouth 911 tandem.

                                    15.6.1.10.2 S911 TRUNKS

                                    In areas where S911 tandems are used,
                                    BellSouth shall allow MCIm to provide direct
                                    trunking to each BellSouth S911 tandem. Such
                                    SS7 trunks are to be provided as one-way
                                    trunks from a given MCIm end-office to the
                                    BellSouth S911 tandem.

                                    15.6.1.10.3 LOCAL SWITCH AND ACCESS TANDEM
                                    TRUNKS

                                         15.6.1.10.3.1 BellSouth shall provide
                                         trunks groups provisioned exclusively
                                         to carry intraLATA traffic, as
                                         designated by MCIm.

                                         15.6.1.10.3.2 BellSouth shall provide
                                         trunk groups provisioned exclusively to
                                         carry interLATA traffic, as designated
                                         by MCIm.

                                         15.6.1.10.3.3 BellSouth shall provide
                                         SS7 trunks

                                                            Attachment III - 100
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                         which provide SS7 interconnection. At
                                         MCIm' s request, MF trunks may be
                                         substituted for SS7 trunks where
                                         applicable.

                                         15.6.1.10.3.4 When and if Technically
                                         Feasible, BellSouth shall
                                         simultaneously route calls based on
                                         dialed digits (in accordance with the
                                         standard GR-317-CORE), and Carrier
                                         Identification Code (in accordance
                                         with the standard GR-394-CORE) over
                                         a single SS7 trunk group.

                                    15.6.1.10.4 BELLSOUTH OPERATOR SERVICES
                                    TRUNK

                                         15.6.1.10.4.1 For traffic from the
                                         BellSouth network to MCIm for
                                         Operator Services, BellSouth shall
                                         provide one trunk group per NPA served
                                         by the local BellSouth switch.

                                         15.6.1.10.4.2 BellSouth shall provide
                                         such trunks as one-way trunks from the
                                         BellSouth network to the MCIm network.

                  15.6.2   Network Interconnection between BellSouth and MCIm
                  shall meet or exceed all of the requirements for Network
                  Interconnection set forth in the following technical
                  references:

                           15.6.2.1 GR-317-CORE, Switching System generic
                           requirements for Call Control Using the Integrated
                           Services Digital Network User Part (ISDNUP),
                           Bellcore, February, 1994;

                           15.6.2.2 GR-394-CORE, Switching System generic
                           requirements for Interexchange Carrier
                           Interconnection Using the Integrated Services Digital
                           Network User Part (ISDNUP), Bellcore, February, 1994;

                           15.6.2.3 FR-NWT-000271, OSSGR Operator Services
                           Systems generic requirements, Bellcore, 1994 Edition;
                           and

                           15.6.2.4 FR-NWT-000064, LATA Switching Systems
                           Generic Requirements (LSSGR), Bellcore, 1994 Edition.

SECTION 16. BASIC 911 AND E911

See Attachment VIII, Section 6.1.1 911 General Requirements and Section 6.2.1
911 System Interface and Exchanges

                                                            Attachment III - 101
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

SECTION 17. DIRECTORY ASSISTANCE DATA

See Attachment VIII, Section 6.1.6, Directory Assistance Data General
Requirements and Section 6.2.2, Directory Assistance Data Interfaces and
Exchanges.

                                                            Attachment III - 102
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                               TABLE OF CONTENTS

                                 ATTACHMENT IV
                                INTERCONNECTION

Section 1.    Local Interconnection Trunk Arrangement           IV - 1

Section 2.    Compensation Mechanisms                           IV - 2

Section 3.    Signaling                                         IV - 4

Section 4.    Network Servicing                                 IV - 5

Section 5.    Network Management                                IV - 9

Section 6.    Busy Line Verify and Interrupt                    IV - 9

Section 7.    Usage Measurement                                 IV - 10

Section 8.    Responsibilities of the Parties                   IV - 10


                                                               Attachment IV - i
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                                 ATTACHMENT IV

                                INTERCONNECTION


SECTION 1.      LOCAL INTERCONNECTION TRUNK ARRANGEMENT

A. One-way and two-way trunks. The parties may use either one-way or two-way
trunking or a combination, as mutually agreed.

         1.1 The parties shall initially reciprocally terminate local exchange
         traffic and IntraLATA/InterLATA toll calls originating on each other's
         networks as follows:

               1.1.1 The parties shall make available to each other either one
               way or two-way trunks for the reciprocal exchange of combined
               local traffic and non-equal access IntraLATA toll traffic

               1.1.2 Separate two-way trunks will be made available for the
               exchange of equal-access InterLATA or IntraLATA interexchange
               traffic that transits BellSouth's network, and local transit
               traffic to other LECs. Local transit traffic to other LECs shall
               only be assessed the local interconnection charge.

               1.1.3 Separate trunks connecting MCIm's switch to each 911/E911
               tandem.

               1.1.4 Separate trunk group connecting MCIm's switch to
               BellSouth's operator service center for operator-assisted busy
               line interrupt/verify. MCIm, at its option, may establish trunks
               from its own operator services platform directly to BellSouth's
               operator service center.

               1.1.5 Separate trunk group connecting MCIm's switch to
               BellSouth's directory assistance center in instances where MCIm
               is purchasing BellSouth's unbundled directory assistance
               service.

               1.1.6 The parties shall attempt to develop a solution whereby
               local, interLATA and intraLATA traffic may all be combined on a
               single trunk group.

         1.2 Interconnection Point
                                                               Attachment IV - 1
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

               1.2.1 BellSouth "Interconnection Point" or "IP" means the
               physical point that establishes the technical interface, the test
               point, and the operational responsibility hand-off between MCIm
               and BellSouth for the local interconnection of their networks.
               MCIm will separate traffic destined for different tandems onto
               separate trunk groups at the IP.

               1.2.2 MCIm shall designate at least one IP in the LATA in which
               MCIm originates local traffic and interconnects with BellSouth.
               MCIm will be responsible for engineering and maintaining its
               network on its side of the IP. BellSouth will be responsible for
               engineering and maintaining its network on its side of the IP. If
               and when the parties choose to interconnect at a mid-span meet,
               MCIm and BellSouth will jointly provision the fiber optic
               facilities that connect the two networks and shall share the
               financial and other responsibilities for that facility.

               1.2.2.1 Upon MCIm's request for additional points of
               interconnection, BellSouth will interconnect with MCIm at any
               Technically Feasible point on BellSouth's network of MCIm's
               choosing using the same technical configuration or using other
               arrangements, including but not limited to mutually agreed upon
               mid-span fiber meets, entrance facilities, telco closets, and
               physical or virtual collocation.

               1.2.2.2 Within three (3) business days of MCIm's written request
               for IP, BellSouth shall identify any known Environmental Hazard
               or Hazardous Materials existing in the IP route or location.

               1.2.2.3 BellSouth shall allow MCIm to perform any environmental
               site investigations, including, but not limited to, asbestos
               surveys, MCIm deems to be necessary in support of its collocation
               needs, at MCIm's request.

               1.2.2.4 If interconnection is complicated by the presence of
               Environmental Hazards or Hazardous Materials, and an alternative
               route is available, BellSouth shall make such alternative route
               available for MCIm's consideration.

SECTION 2. COMPENSATION MECHANISMS

         2.1 Interconnection Point

               2.1.1 Each party is responsible for bringing their facilities to
               the IP.

                                                             Attachment IV - 2
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

         2.2 Compensation for Call Traffic Transport and Termination

               2.2.1 The Parties shall bill each other reciprocal compensation
               at the rates set forth for Local Interconnection in this
               Agreement and the Order of the MPSC. Local Traffic is defined as
               any telephone call that originates in one exchange and terminates
               in either the same exchange, or a corresponding Extended Area
               (EAS) exchange. The terms Exchange and EAS exchanges are defined
               and specified in Section A3. Of BellSouth's General Subscriber
               Service Tariff.

                  2.2.1.1 BellSouth shall provide to MCIm, on diskette(s) or in
                  any other manner that the parties agree to, on a one-time
                  basis when requested by MCIm, an all-inclusive list
                  (BellSouth, LEC, CLEC and EAS NXX's) of NXX's pertaining to
                  section 2.2.1, above, that creates parity with that which
                  BellSouth provides to itself. MCIm may require, upon request,
                  updates to this list.

               2.2.2 The IP determines the point at which the originating
               carrier shall pay the terminating carrier for the completion of
               that traffic. The following compensation elements shall apply:

                  2.2.2.1 "Transport", which includes the transmission and any
                  necessary tandem switching of local telecommunications traffic
                  from the interconnection point between the two carriers to the
                  terminating carrier's end-office switch that directly serves
                  the called end-user.

                  2.2.2.2 "Termination", which includes the switching of Local
                  Traffic at the terminating carrier's end office switch.

         2.3 When an MCIm subscriber places a call to BellSouth's subscriber,
         MCIm will hand off that call to BellSouth at the IP. Conversely, when
         BellSouth hands over local traffic to MCIm for MCIm to transport and
         terminate, BellSouth must use the established IP.

         2.4 MCIm may designate an IP at any Technically Feasible point
         including but not limited to any electronic or manual cross-connect
         points, collocations, telco closets, entrance facilities, and mid-span
         meets where mutually agreed upon. The transport and termination charges
         for local traffic flowing through an IP shall be as follows:

               2.4.1 Left Blank Intentionally

                                                              Attachment IV - 3
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement


               2.4.2 Left Blank Intentionally

               2.4.3 Left Blank Intentionally

SECTION 3. SIGNALING

         3.1 Signaling protocol. The parties will interconnect their networks
         using SS7 signaling as defined in GR-317 and GR-394 including ISDN User
         Part ("ISUP") for trunk signaling and Transaction Capabilities
         Application Part ("TCAP") for CCS-based features in the interconnection
         of their networks. All Network Operations Forum (NOF) adopted standards
         shall be adhered to.

         3.2 The parties will provide CCS to each other in conjunction with all
         trunk groups supporting local, transit, and toll traffic. The parties
         will cooperate on the exchange of Transactional Capabilities
         Application Part (TCAP) messages to facilitate full inter-operability
         of CCS-based features between their respective networks, including all
         CLASS features and functions. All CCS signaling parameters will be
         provided including automatic number identification (ANI), originating
         line information (OLI), calling party category, charge number, etc. All
         privacy indicators will be honored.

               3.2.1 OSS7, while planned by BellSouth, is not presently
               available.

         3.3 Refer to Attachment III, Section 15.5 for detailed terms of SS7
         Network Interconnection.

         3.4 Both parties agree that the standard interconnection facilities
         shall be Extended Superframe (ESF) with B8ZS line code. Where ESF/B8ZS
         is not available, MCIm will agree to using other interconnection
         protocols on an interim basis until the standard ESF/B8ZS is available.
         BellSouth will provide anticipated dates of availability for those
         areas not currently ESF/B8ZS compatible.

               3.4.1 Where MCIm is unwilling to utilize an alternate
               interconnection protocol, MCIm will provide BellSouth an initial
               forecast of 64 Kbps Clear Channel Capability ("64K CCC") trunk
               quantities within 30 days of executing this Agreement, consistent
               with the forecasting agreements between the parties. Upon receipt
               of this forecast, the parties will begin joint planning for the
               engineering, procurement, and installation of the segregated 64K
               CCC Local Interconnection Trunk Groups, and the associated B8ZS
               Extended Super Frame ("ESF") facilities, for the sole


                                                              Attachment IV - 4
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

               purpose of transmitting 64K CCC data calls between MCIm and
               BellSouth. Where additional equipment is required, such equipment
               would be obtained, engineered, and installed on the same basis
               and with the same intervals as any similar growth job for IXC,
               CLEC or ILEC internal subscriber demand for 64K CCC trunks. Where
               Technically Feasible, these trunks will be established as
               two-way.

SECTION 4. NETWORK SERVICING

         4.1 TRUNK FORECASTING:

               4.1.1 The parties shall work towards the development of joint
               forecasting responsibilities for traffic utilization over trunk
               groups. Orders for trunks that exceed forecasted quantities for
               forecasted locations will be accommodated as facilities and or
               equipment are available. Parties shall make all reasonable
               efforts and cooperate in good faith to develop alternative
               solutions to accommodate orders when facilities are not
               available. Intercompany forecast information must be provided by
               the parties to each other twice a year. BellSouth's forecast
               will be provided thirty (30) days following the receipt of the
               MCIm forecast. The semi-annual forecasts shall include:

                  4.1.1.1 Yearly forecasted trunk quantities (which include
                  measurements that reflect actual tandem and end office Local
                  Interconnection and future meet point trunks and
                  tandem-subtending Local Interconnection end office equivalent
                  trunk requirements for no more than two years (current plus
                  one year));

                  4.1.1.2 The use of Common Language Location Identifier
                  (CLLI-MSG), which are described in Bellcore documents BR
                  795-100-100 and BR 795-400-100;

                  4.1.1.3 Description of major network projects that affect the
                  other party will be provided in the semi-annual forecasts.
                  Major network projects include but are not limited to trunking
                  or network rearrangements, shifts in anticipated traffic
                  patterns, or other activities by either party that are
                  reflected by a significant increase or decrease in trunking
                  demand for the following forecasting period.

               4.1.2 Parties shall meet to review and reconcile their forecasts
               if forecasts vary significantly. The parties shall mutually agree
               to the


                                                               Attachment IV - 5
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

               over or under trunk group utilization prior to action being taken
               on the following;

                  4.1.2.1 If the parties are unable to reach such a
                  reconciliation, the Local interconnection Trunk Groups shall
                  be provisioned to the higher forecast. At the end of three
                  months, the utilization of the Local Interconnection Trunk
                  Groups will be reviewed and if the average CCS utilization for
                  the third month is under seventy-five percent (75%) of
                  capacity, either party may issue an order to resize the trunk
                  group, which shall be left with not less than twenty-five
                  percent (25%) excess capacity.

                  4.1.2.2 If the parties agree on the original forecast and then
                  it is determined that a trunk group is under seventy-five
                  percent (75%) of CCS capacity on a monthly-average basis for
                  each month of any six-month period, either party may issue an
                  order to resize the trunk group, which shall be left with not
                  less than twenty-five percent (25%) excess capacity.

               4.1.3 Each party shall provide a specified point or points of
               contact for planning Forecasting and trunk servicing purposes.

               4.1.4 Trunking can be established to tandems or end offices or a
               combination of both via either one-way or two-way trunks.
               Trunking will be at the DS-0 level, DS-1 level, DS-3/OC-3 level,
               or higher, as designated by MCIm. Initial trunking will be
               established between the MCIm switching centers and BellSouth' s
               access tandem(s). The parties will utilize direct end office
               trunking under the following conditions:

                  4.1.4.1 Tandem Exhaust - If a tandem through which the parties
                  are interconnected is unable to, or is forecasted to be unable
                  to, support additional traffic loads for any period of time,
                  the parties will mutually agree on an end office trunking plan
                  that will alleviate the tandem capacity shortage and ensure
                  completion of traffic between MCIm and ILEC subscribers.

                  4.1.4.2 Traffic volume - The parties shall install and retain
                  direct end office trunking sufficient to handle actual or
                  reasonably forecasted traffic volumes, whichever is greater,
                  between an MCIm switching center and a BellSouth end office
                  where the traffic exceeds or is forecast to exceed


                                                               Attachment IV - 6
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  220,000 minutes of local traffic per month. The parties will
                  install additional capacity between such points when overflow
                  traffic between the MCIm switching center and ILEC access
                  tandem exceeds or is forecast to exceed 220,000 minutes of
                  local traffic per month.

                  4.1.4.3 Mutual Agreement - The parties may install direct end
                  office trunking upon mutual agreement in the absence of
                  conditions (1) or (2) above and agreement will not
                  unreasonably be withheld.

         4.2 GRADE OF SERVICe:

               4.2.1 A blocking standard of one percent (.01) during the average
               busy hour, as defined by each party's standards, for final trunk
               groups between a MCIm end office and a BellSouth access tandem
               carrying meet point traffic shall be maintained. All other final
               trunk groups are to be engineered with a blocking standard of one
               percent (.01). Direct end office trunk groups are to be
               engineered with a blocking standard of one percent (.01). The
               blocking standard of one half of one percent (.005) will be used
               on trunk groups carrying interlata traffic.

               4.2.2 For trunks carrying MCIm interlata traffic, MCIm may
               request BellSouth to report trunk group service performance and
               blocking standards to the industry.

         4.3 TRUNK SERVICING

               4.3.1 Orders between the parties to establish, add, change or
               disconnect trunks shall be processed by use of an Access Service
               Request (ASR), or another industry standard eventually adopted to
               replace the ASR for local service ordering.

               4.3.2 As discussed in this Agreement, both parties will jointly
               manage the capacity of Local Interconnection Trunk Groups.
               BellSouth's or MCIm's Trunk Servicing Group will send a Trunk
               Group Service Request (TGSR) to the other party to trigger
               changes they desire to the Local Interconnection Trunk Groups
               based on their capacity assessment. The affected party will issue
               an ASR to the other party:

                  4.3.2.1 within ten (10) business days after receipt of the
                  TGSR upon review of and in response to BellSouth's TGSR, or

                                                               Attachment IV - 7
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

                  4.3.2.2 at any time as a result of either party's own
                  capacity management assessment, to begin the provisioning
                  process.

               4.3.3 The standard interval used for the provisioning of Local
               Interconnection Trunk Groups shall be determined by Subscriber
               Desired Due Date, but in no event shall it be longer than ten
               (10) working days.

               4.3.4 Orders that comprise a major project that directly impacts
               the other party may be submitted at the same time, and their
               implementation shall be jointly planned and coordinated. Major
               projects are those that require the coordination and execution of
               multiple orders or related activities between and among BellSouth
               and MCIm work groups, including but not limited to the initial
               establishment of Local Interconnection or Meet Point trunk groups
               and service in an area, NXX code moves, re-homes, facility
               grooming, or network rearrangements.

               4.3.5 MCIm and BellSouth agree to exchange escalation lists which
               reflect contact personnel including vice president-level
               officers. These lists shall include name, department, title,
               phone number, and fax number for each person. MCIm and BellSouth
               agree to exchange an up-to-date list on a quarterly basis.

SECTION 5. NETWORK MANAGEMENT

         5.1 Protective Protocols

               5.1.1 Either party may se protective network traffic management
               controls such as 7-digit and 10-digit code gaps on traffic toward
               each others network, when required to protect the public switched
               network from congestion due to facility failures, switch
               congestion or failure or focused overload. MCIm and BellSouth
               will immediately notify each other of any protective control
               action planned or executed.

         5.2 Expansive Protocols

               5.2.1 Where the capability exists, originating or terminating
               traffic reroutes may be implemented by either party to
               temporarily relieve network congestion due to facility failures
               or abnormal calling patterns. Reroutes will not be used to
               circumvent normal trunk

                                                               Attachment IV - 8
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

               servicing. Expansive controls will only be used when mutually
               agreed to by the parties.

         5.3 Mass Calling

               5.3.1 MCIm and BellSouth shall cooperate and share pre-planning
               information, where available, regarding cross-network call-ins
               expected to generate large or focused temporary increases in call
               volumes, to prevent or mitigate the impact of these events on the
               public switched network. Parties agree that permanent controls
               should be in place for NXX's that are dedicated for media
               stimulated mass calling.

SECTION 6. BUSY LINE VERIFY AND INTERRUPT

         6.1 Description: Each party shall establish procedures whereby its
         operator bureau will coordinate with the operator bureau of the other
         party in order to provide Busy Line Verification ("BLV") and Busy Line
         Verification and Interrupt ("BLVI") services on calls between their
         respective end users on or before the effective date of this agreement.

         6.2 Compensation: Each party shall charge the other party for BLV and
         BLVI at rates specified in Attachment I.

SECTION 7. USAGE MEASUREMENT

         7.1 Each party shall calculate terminating interconnection minutes of
         use based on standard Automatic Message Accounting (AMA) recordings
         made within each party's network. These recordings being necessary for
         each party to generate bills to the other party.

         7.2 Measurement of minutes of use over Local Interconnection Trunk
         groups shall be in actual conversation seconds. The total conversation
         seconds over each individual Local Interconnection Trunk Group will be
         totaled for the entire monthly bill-round and then rounded to the next
         whole minute.

         7.3 Where MCIm provides local exchange services via switch facilities,
         each party shall provide to the other, within 20 calendar days after
         the end of each BellSouth fiscal quarter (commencing with the first
         full fiscal quarter after the effective date of this agreement), a
         usage report with the following information regarding traffic
         originating from facilities provided by the originating party and
         terminated over the Local Interconnection Trunk Groups:

                                                               Attachment IV - 9
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

               7.3.1 Total traffic volume described in terms of minutes and
               messages and by call type (local, toll, and other) at the state
               level terminated to each other over the Local Interconnection
               Trunk Groups and

               7.3.2. Percent Local Use (PLU)

SECTION 8. RESPONSIBILITIES OF THE PARTIES

         8.1 BellSouth and MCIm agree to treat each other fairly,
         nondiscriminatorily, and equally for all items included in this
         Agreement, or related to the support of items included in this
         Agreement.

         8.2 MCIm and BellSouth agree to exchange such reports and/or data as
         provided in this Attachment in Section 7.3 to facilitate the proper
         billing of traffic. Either party may request an audit of such usage
         reports on no fewer than 10 business days' written notice and any audit
         shall be accomplished during normal business hours at the office of the
         party being audited. Such audit must be performed by a mutually
         agreed-to independent auditor paid for by the party requesting the
         audit and may include review of the data described in Section 7 above.
         Such audits shall be requested within six months of having received the
         PLU factor and usage reports from the other party.

         8.3 MCIm and BellSouth will review engineering requirements on a
         semi-annual basis and establish forecasts for trunk and facilities
         utilization provided under this Agreement. BellSouth and MCIm will work
         together to begin providing these forecasts within 30 days from the
         Effective Date of this Agreement. New trunk groups will be implemented
         as dictated by engineering requirements for either BellSouth or MCIm.

         8.4 MCIm and BellSouth shall share responsibility for all Control
         Office functions for Local Interconnection Trunks and Trunk Groups, and
         both parties shall share the overall coordination, installation, and
         maintenance responsibilities for these trunks and trunk groups.

         8.5 MCIm is responsible for all Control Office functions for the meet
         point trunking arrangement trunks and trunk groups, and shall be
         responsible for the overall coordination, installation, and maintenance
         responsibilities for these trunks and trunk groups.

         8.6 MCIm and BellSouth shall:

               8.6.1 Provide trained personnel with adequate and compatible test
               equipment to work with each other's technicians.

                                                              Attachment IV - 10
<PAGE>

              MCIm-BellSouth Mississippi Interconnection Agreement

               8.6.2 Notify each other when there is any change affecting the
               service requested, including the due date.

               8.6.3 Coordinate and schedule testing activities of their own
               personnel, and others as applicable, to ensure its
               interconnection trunks/trunk groups are installed per the
               interconnection order, meet agreed-upon acceptance test
               requirements, and are placed in service by the due date.

               8.6.4 Perform sectionalization to determine if a trouble is
               located in its facility or its portion of the interconnection
               trunks prior to referring the trouble to each other.

               8.6.5 Advise each other's Control Office if there is an
               equipment failure which may affect the interconnection trunks.

               8.6.6 Provide each other with a trouble reporting/repair contact
               number that is readily accessible and available 24 hours/7 days a
               week. Any changes to this contact arrangement must be immediately
               provided to the other party.

               8.6.7 Provide to each other test-line numbers and access to test
               lines.

               8.6.8 Cooperatively plan and implement coordinated repair
               procedures for the mutually agreed upon meet point and Local
               Interconnection Trunks and facilities to ensure trouble reports
               are resolved in a timely and appropriate manner.

               8.6.9 The parties shall meet and mutually agree to network
               protocols which include but are not limited to glare parameters,
               number of digits outpulsed, OZZ codes and 800 CIC codes in use.

                                                              Attachment IV - 11
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                               TABLE OF CONTENTS

                                  ATTACHMENT V
                                  COLLOCATION

Section 1. Introduction                                 V - 1

Section 2. Technical Requirements                       V - 1

Section 3. License                                      V - 8

Section 4. Technical References                         V - 8












                                                                Attachment V - i
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                                  ATTACHMENT V

                                  COLLOCATION
SECTION 1. INTRODUCTION

This Attachment sets forth the requirements for Collocation.

SECTION 2. TECHNICAL REQUIREMENTS

         2.1 BellSouth shall provide space, as requested by MCIm, to meet MCIm's
         needs for placement of equipment, interconnection, or provision of
         service.

               **2.1.1. Within three (3)business days of MCIm's written
               request, BellSouth shall identify any known Environmental Hazard
               or Hazardous Materials in the space provided for placement of
               equipment and interconnection.

               2.1.2 BellSouth shall allow MCIm to perform any environmental
               site investigations, including, but not limited to, asbestos
               surveys, which MCIm deems to be necessary in support of its
               collocation needs, at MCIm's expense.

               2.1.3 If the space provided for the placement of equipment,
               interconnection, or provision of service contains environmental
               contamination or hazardous material, particularly but not limited
               to asbestos, lead paint or radon, which makes the placement of
               such equipment or interconnection hazardous, BellSouth shall
               offer an alternative space, if available, for MCIm's
               consideration.

               2.1.4 MCIm shall provide BellSouth with a list of identified
               Hazardous Materials which at the time of the request meet the
               definition of Environmental Hazard in Part B that are contained
               in any equipment it proposes to place in space provided by
               BellSouth and must obtain written approval for the installation
               of such equipment prior to placement of the equipment in the
               space. Failure to obtain the appropriate written approval from
               BellSouth prior to placement of equipment represents a breach of
               this agreement and may result in the loss of MCIm's right to use
               the space.

                                                                Attachment V - 1
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         2.2 BellSouth shall provide intraoffice facilities (e.g., DS0, DS1,
         DS3, OC3, OC12, OC48, and STS-1 terminations) as requested by MCIm to
         meet MCIm's need for placement of equipment, interconnection, or
         provision of service.

         2.3 BellSouth agrees to allow MCIm's employees and designated agents
         unrestricted access to MCIm dedicated space in manned BellSouth offices
         twenty-four (24) hours per day each day of the week. BellSouth may
         place reasonable security restrictions on access by MCIm's employees
         and designated agents to the MCIm collocated space in unmanned
         BellSouth offices. Notwithstanding, BellSouth agrees that such space
         shall be available to MCIm's employees and designated agents
         twenty-four (24) hours per day each day of the week.

         2.3A A security escort may be required for access to BellSouth premises
         or MCIm space in some locations for non-BellSouth personnel. MCIm
         agrees to provide its employees who will access the space with a
         picture identification badge containing the employee name, a recent
         photograph of the employee and the MCIm company name and/or logo. Agent
         representatives will be required to have an identification badge
         containing the representative's name and company name.

         2.4 MCIm may collocate the amount and type of equipment it deems
         necessary in its collocated space in accordance with FCC Rules and
         Regulations. BellSouth shall not restrict the types of equipment or
         vendors of equipment to be installed, provided such equipment is for
         the provision of telecommunications service. All equipment placed in an
         BellSouth space for collocation must meet applicable industry
         standards.

         2.5 BellSouth shall permit the interconnection of a collocating
         telecommunications carrier network with that of another collocating
         telecommunications carrier at the BellSouth premises and the
         interconnection of collocated equipment to the collocated equipment of
         another telecommunications carrier within the same premises through the
         purchase of BellSouth cross-connects.

               2.5.1 Subject to Section 2.5, MCIm may choose to lease unbundled
               transport from the BellSouth, or from a third carrier, rather
               than construct facilities to the BellSouth central office or
               facility where equipment will be collocated.

               2.5.2 Charges for all services provided pursuant to this
               Attachment shall be as set forth in Attachment I.


                                                                Attachment V - 2
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         2.6 BellSouth shall permit MCIm to subcontract the construction of
         cages and the installation of physical collocation equipment
         arrangements with contractors certified by the BellSouth, provided,
         however, that the BellSouth shall not unreasonably withhold
         certification of contractors. Certification by a BellSouth shall be
         based on the same criteria it uses in approving contractors for its own
         purposes.

         2.7 BellSouth shall provide basic telephone service at the tariffed
         rate for basic service with a connection jack as requested by MCIm from
         BellSouth for the collocated space. Upon MCIm's request, this service
         shall be available at the MCIm collocated space on the day that the
         space is turned over to MCIm by BellSouth.

         2.8 BellSouth shall provide adequate lighting, ventilation, power,
         heat, air conditioning, and other environmental conditions for MCIm's
         space and equipment. These environmental conditions shall adhere to
         Bell Communication Research (Bellcore) Network Equipment-Building
         System (NEBS) standards TR-EOP-000063.

         2.9 BellSouth shall provide access to eyewash stations, shower
         stations, bathrooms, and drinking water, where available, within the
         collocated facility on a twenty-four (24) hours per day, seven (7) days
         per week basis for MCIm personnel and its designated agents.

         2.10 MCIm may request dual fiber entrance to the BellSouth Central
         Office. Where dual entrance is available, BellSouth shall provide all
         ingress and egress of MCIm fiber cabling to MCIm collocated spaces .
         The specific request for diversity for each site will be provided by
         MCIm in the collocation application request.

         2.11 BellSouth shall ensure protection of MCIm's proprietary subscriber
         information. Any collocation arrangement shall include provisions for
         BellSouth protecting MCIm's proprietary information.

         2.12 BellSouth shall participate in and adhere to negotiated service
         guarantees, and Performance Standards.

         2.13 BellSouth shall provide MCIm with written notice five (5) business
         days prior to those instances where BellSouth or its subcontractors may
         be performing work in the general area of the collocated space occupied
         by MCIm, or in the general area of the AC and DC power plants which
         support MCIm equipment that may directly impact MCIm's equipment
         arrangement, facilities, or power supply. BellSouth will inform MCIm by
         telephone of such emergency related activity that BellSouth or its



                                                                Attachment V - 3
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         subcontractors may be performing in the general area of the collocated
         space occupied by MCIm, or in the general area of the AC and DC power
         plants which support MCIm equipment that may directly impact MCIm's
         equipment arrangement, facilities or power supply. Notification of any
         emergency related activity shall be made immediately prior to the start
         of the activity so that MCIm can take any action required to monitor or
         protect its service.

         2.14 BellSouth shall construct the collocated space in compliance with
         MCIm's collocation request. Any deviation to MCIm's request will be
         jointly negotiated between the parties.

         2.15 MCIm and BellSouth will complete an acceptance walk through of
         collocated space requested from BellSouth. BellSouth will correct any
         deviations to MCIm's original or jointly amended request within 5
         business days after the walk through or a negotiated time frame,
         depending on the magnitude of the deviation, at BellSouth's expense.
         Any other additions or changes to the original or jointly amended
         request will be at MCIm's expense.

         2.16 BellSouth shall provide Telephone Equipment drawings depicting the
         exact location for BellSouth Point of Termination Bay(s) to MCIm at the
         first joint planning meeting.

         2.17 A joint planning meeting between BellSouth and MCIm will commence
         within a maximum of seven (7) business days, unless the parties jointly
         agree upon a later date, from BellSouth's receipt of a complete and
         accurate firm order and the payment of agreed upon fees. The following
         information will be exchanged or determined at the meeting.

               2.17.1 Telephone equipment drawings depicting the exact path with
               dimensions for MCIm Outside Plant Fiber ingress and egress into
               collocated space.

               2.17.2 BellSouth shall provide power cabling connectivity
               information including the sizes and number of power feeders and
               power feeder fuse slot assignment on the BellSouth BDFB.

               2.17.3 Work restriction guidelines.

               2.17.4 BellSouth contacts and escalation process (names and
               telephone numbers and escalation order) for the following areas:

                        Engineering
                        Provisioning


                                                                Attachment V - 4
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                        Billing
                        Operations
                        Physical & Logical Security
                        Site and Building Managers
                        Environmental and Safety

               2.17.5 The target date for the release of BellSouth engineering
               documents which shall include, but not be limited to, connector
               type, number and type of pairs, and naming convention.

               2.17.6 Target commencement date, which shall be the date MCIm's
               equipment is turned up and operational on the BellSouth network.

         2.18 Left blank intentionally

         2.19 Left blank intentionally

         2.20 MCIm shall be compensated by BellSouth for any delays in the
         negotiated completion and turnover dates which create expenditures for
         MCIm. MCIm wil be reimbursed in the amount equal to the MCIm
         expenditures incurred as a direct result of delays created by
         BellSouth. Such expenditures may include items such as lease extension
         penalties incurred when MCIm could not vacate a leased property on or
         by the central office space availability date originally committed by
         Bellsouth, as a result of delays on BellSouth's part.

         2.21 MCIm agrees to place operational telecommunications equipment in
         the BellSouth premises and connect with BellSouth's network within one
         hundred eighty (180) days of the space turnover date, unless the
         parties mutually agree to extend such timeframe. MCIm forfeits its
         rights to use the space on the thirtieth day after BellSouth provides
         MCIm written notice of such failure if MCIm does not place operational
         telecommunications equipment in the premises and connect with
         BellSouth's network by such thirtieth day. In any such event, MCIm
         shall be liable in an amount equal to the unpaid balance of the
         preparation charges due pursuant to Section 2.17 of this Attachment.

         2.22 Power as referenced in this document refers to any electrical
         power source supplied by BellSouth for MCIm equipment. It includes all
         superstructure, infrastructure, and overhead facilities, including, but
         not limited to, cable, cable racks and bus bars. BellSouth will supply
         power to support MCIm equipment at equipment specific DC and AC
         voltages. BellSouth shall supply power to MCIm at parity with that
         provided by BellSouth to itself or to any third party. If BellSouth
         performance, availability, or restoration falls below industry
         standards, BellSouth shall


                                                                Attachment V - 5
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         bring itself into compliance with such industry standards as soon as
         technologically feasible.

               2.22.1 Central office power supplied by BellSouth into the MCIm
               equipment area, shall be supplied in the form of power feeders
               (cables) on cable racking into the designated MCIm equipment
               area. MCIm's certified vendor shall be responsible for the
               installation of power cabling from BellSouth's power
               distribution frame associated with the collocation space to the
               designated MCIm equipment area. The power feeders (cables) shall
               efficiently and economically support the requested quantity and
               capacity of MCIm equipment. The termination location shall be as
               requested by MCIm. Any deviations will be jointly negotiated by
               BellSouth and MCIm.

               2.22.2 BellSouth shall provide power as requested by MCIm to meet
               MCIm's need for placement of equipment, interconnection, or
               provision of service.

               2.22.3 BellSouth power equipment supporting MCIm's equipment
               shall:

                  2.22.3.1 Comply with applicable industry standards (e.g.,
                  Bellcore and NEBS) or manufacturer's equipment power
                  requirement specifications for equipment installation and
                  physical equipment layout;

                  2.22.3.2 Have redundant power feeds with physical diversity
                  and battery back-up at parity with that provided for similar
                  BellSouth equipment;

                  2.22.3.3 Provide, upon MCIm's request via the BFR process, the
                  capability for real time access to performance monitoring and
                  alarm data that impacts (or potentially may impact) MCIm
                  traffic;

                  2.22.3.4 Provide central office ground, connected to a ground
                  electrode located within the MCIm collocated space, at a
                  location which meets BellSouth's Standards and is jointly
                  agreed upon by the parties at the initial planning meeting
                  identified in Section 2.17 preceding of this Attachment V;

                  2.22.3.5 Provide feeder capacity and quantity to support the
                  ultimate equipment layout for MCIm equipment in

                                                                Attachment V - 6
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

                  accordance with MCIm's collocation request.

                  2.22.3.6 BellSouth shall, within ten (10) days of MCIm's
                  request:

                        2.22.3.6.1 Permit MCIm to inspect supporting documents
                        for contracted work done on behalf of MCIm (i.e. AIA
                        document G702);

                        2.22.3.6.2 Provide an installation sequence and access
                        that will allow installation efforts in parallel without
                        jeopardizing personnel safety or existing MCIm services;

                        2.22.3.6.3 Provide power plant alarms that adhere to
                        Bell Communication Research (Bellcore) Network
                        Equipment-Building System (NEBS) standards TR- EOP-
                        000063, upon MCIm's request via the BFR process;

                        2.22.3.6.4 Provide cabling that adheres to Bell
                        Communication Research (Bellcore) Network
                        Equipment-Building System (NEBS) standards TR- EOP-
                        000063;

                        2.22.3.6.5 Provide Lock Out-Tag Out and other electrical
                        safety procedures and devices in conformance with the
                        most stringent of OSHA or industry guidelines.

                  2.22.4 BellSouth will provide MCIm with written notification
                  within ten (10) business days of any scheduled AC or DC power
                  work or related activity in the collocated facility that will
                  or might cause an outage or any type of power disruption to
                  MCIm equipment located in BellSouth facility. BellSouth shall
                  provide MCIm immediate notification by telephone of any
                  emergency power activity that would impact MCIm equipment.

         2.23 BellSouth shall provide virtual collocation where physical
         collocation is not practical for technical reasons or because of space
         limitations. BellSouth shall take collocator demand into account when
         renovating existing facilities and constructing or leasing new
         facilities.

         2.24 Unless abatement of an Environmental Hazard or Hazardous Materials
         is required, Intervals for physical collocation shall be a

                                                                Attachment V - 7
<PAGE>

            MCImetro-BellSouth Mississippi Interconnection Agreement

         maximum of ninety (90) days from the date BellSouth receives MCIm's
         firm order request. Requirements, terms and conditions for virtual
         collocation will be pursuant to section 20 of BellSouth's FCC #1
         tariff.

         2.25 Insurance requirements for collocation are subject to the
         provisions of section 11.7 of Part A of this Agreement.

SECTION 3. LICENSE - LEFT BLANK INTENTIONALLY

SECTION 4. TECHNICAL REFERENCES

BellSouth agrees to comply with all Bellcore and ANSI standards that are
directly applicable to construct, supply and maintain collocation facilities.
Such standards may include, without limitation:

        National Electrical Code (NEC)
        NEBS Generic Engineering Requirements for System Assembly
          and Cable Distribution (Bellcore)
        Generic Requirements for -24, -48, -130, and -140 volt central
          office power plant rectifiers (Bellcore)



                                                                Attachment V - 8
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                                  ATTACHMENT VI

               Rights of Way (ROW), Conduits, and Pole Attachments



                                TABLE OF CONTENTS


1.   RIGHTS OF WAY (ROW), CONDUITS AND POLE ATTACHMENTS                     1

2.   UNUSED TRANSMISSION MEDIA                                             40

                                                               Attachment VI - i
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement


                                  Attachment VI


               Rights of Way (ROW), Conduits, and Pole Attachments


1.       RIGHTS OF WAY (ROW), CONDUITS AND POLE ATTACHMENTS

This Attachment sets forth the terms and conditions under which BellSouth shall
afford to MCIm access to BellSouth's poles, ducts, conduits and rights-of-way,
pursuant to the Act.

         1.1      DEFINITIONS

                  1.1.1   DEFINITIONS IN GENERAL. Except as the context
                  otherwise requires, the terms defined in this Attachment
                  shall, as used in this Attachment, have the meanings set forth
                  in 1.1.2 through 1.1.30.

                  1.1.2   ANCHOR. The term "anchor" refers to a device,
                  structure, or assembly which stabilizes a pole and holds it in
                  place. An anchor assembly may consist of a rod and fixed
                  object or plate, typically embedded in the ground, which is
                  attached to a guy strand or guy wire, which, in turn, is
                  attached to the pole. The term "anchor" does not include the
                  guy strand which connects the anchor to the pole and includes
                  only those anchors which are owned by BellSouth, as
                  distinguished from anchors which are owned and controlled by
                  other persons or entities.

                  1.1.3   ANCHOR/GUY STRAND. The term "anchor/guy strand" refers
                  to supporting wires, typically stranded together, or other
                  devices attached to a pole and connecting that pole to an
                  anchor or to another pole for the purpose of increasing pole
                  stability. The term "anchor/guy strand" includes, but is not
                  limited to, strands sometimes referred to as "anchor strands,"
                  "down guys," "guy strands," and "pole-to-pole guys."

                  1.1.4   COMMUNICATIONS ACT OF 1934. The terms "Communications
                  Act of 1934" and "Communications Act" refer to the
                  Communications Act of June 19, 1934, 48 Stat. 1064, as
                  amended, including the provisions codified as 47 U.S.C.
                  Sections 151 et seq. The Communications Act includes the Pole
                  Attachment Act of 1978, as defined in this Section 1.1.

                  1.1.5   ASSIGNED. The term "assigned", when used with respect
                  to conduit or duct space or pole attachment space, refers

                                                               Attachment VI - 1
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  to any space in such conduit or duct or on such pole that is
                  occupied by a telecommunications service provider or a
                  municipal or other governmental authority or is assigned
                  pursuant to Section 1.5.5 herein. To ensure the judicious use
                  of poles and conduits, space "assigned" to a
                  telecommunications service provider must be physically
                  occupied by the service provider, be it BellSouth or a new
                  entrant, within twelve (12) months of the space being
                  "assigned".

                  1.1.6   AVAILABLE. The term "available", when used with
                  respect to conduit or duct space or pole attachment space,
                  refers to any usable space in such conduit or duct or on such
                  pole not assigned to a specific provider at the applicable
                  time.

                  1.1.7   CONDUIT OCCUPANCY. The terms "conduit occupancy" and
                  "occupancy" refer to the presence of wire, cable, optical
                  conductors, or other facilities within any portion of
                  BellSouth's conduit system.

                  1.1.8   CONDUIT SYSTEM. The term "conduit system" refers to
                  any combination of ducts, conduits, manholes, and handholes
                  joined to form an integrated whole. In this Attachment, the
                  term refers to conduit systems owned or controlled by
                  BellSouth.

                  1.1.9   COST. The term "cost" as used herein refers to charges
                  made by BellSouth to MCIm for specific work performed, and
                  shall be (a) the actual charges made by subcontractors to
                  BellSouth for work and/or, (b) if the work was performed by
                  BellSouth employees, the rates set forth in Attachment I of
                  this Agreement shall apply for such work.

                  1.1.10  DUCT. The term "duct" refers to a single enclosed
                  tube, pipe, or channel for enclosing and carrying cables,
                  wires, and other facilities. As used in this Attachment, the
                  term "duct" includes "inner ducts" created by subdividing a
                  duct into smaller channels.

                  1.1.11  FACILITIES. The terms "facility" and "facilities"
                  refer to any property or equipment utilized in the provision
                  of telecommunication services.

                  1.1.12  The acronym "FCC" refers to the Federal Communications
                  Commission.

                  1.1.13  INNER-DUCT. The term "inner-duct" refers to a pathway
                  created by subdividing a duct into smaller channels.

                  1.1.14  JOINT USER. The term "joint user" refers to a utility

                                                               Attachment VI - 2
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  which has entered into an agreement with SBT providing
                  reciprocal rights of attachment of facilities owned by each
                  party to the poles, ducts, conduits and rights-of-way owned by
                  the other party.

                  1.1.15  LICENSEE. The term "licensee" refers to a person or
                  entity which has entered or may enter into an agreement or
                  arrangement with BellSouth permitting such person or entity to
                  place its facilities in BellSouth's conduit system or attach
                  its facilities to BellSouth's poles or anchors.

                  1.1.16  LASHING. The term "lashing" refers to the attachment
                  of a licensee's sheath or inner-duct to a supporting strand.

                  1.1.17  LICENSE. The term "license" refers to any license
                  issued pursuant to this Agreement and may, if the context
                  requires, refer to conduit occupancy or pole attachment
                  licenses issued by BellSouth prior to the date of this
                  Agreement.

                  1.1.18  MAKE-READY WORK. The term "make-ready work" refers to
                  all work performed or to be performed to prepare BellSouth's
                  conduit systems, poles or anchors and related facilities for
                  the requested occupancy or attachment of MCIm's facilities.
                  "Make--Ready work" includes, but is not limited to, clearing
                  obstructions (e.g., by "rodding" ducts to ensure clear
                  passage), the rearrangement, transfer, replacement, and
                  removal of existing facilities on a pole or in a conduit
                  system where such work is required solely to accommodate
                  MCIm's facilities and not to meet BellSouth's business needs
                  or convenience. "Make--Ready work" may require "dig-ups" of
                  existing facilities and may include the repair, enlargement or
                  modification of BellSouth's facilities (including, but not
                  limited to, conduits, ducts, handholes and manholes) or the
                  performance of other work required to make a pole, anchor,
                  conduit or duct usable for the initial placement of MCIm's
                  facilities.

                  1.1.19  MANHOLE/HANDHOLE. The term "manhole" refers to an
                  enclosure, usually below ground level and entered through a
                  hole on the surface covered with a cast iron or concrete
                  manhole cover, which personnel may enter and use for the
                  purpose of installing, operating, and maintaining facilities
                  in a conduit. The term "handhole" refers to a similar
                  enclosure which is too small for personnel to enter.

                  1.1.20  OCCUPANCY. The term "occupancy" shall refer to the
                  physical presence of telecommunication facilities in a duct,
                  on a pole, or within a right-of-way.

                                                               Attachment VI - 3
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  1.1.21  PERSON ACTING ON MCIM'S BEHALF. The terms "person
                  acting on MCIm's behalf," "personnel performing work on MCIm's
                  behalf," and similar terms include both natural persons and
                  firms and ventures of every type, including, but not limited
                  to, corporations, partnerships, limited liability companies,
                  sole proprietorships, and joint ventures. The terms "person
                  acting on MCIm's behalf," "personnel performing work on MCIm's
                  behalf," and similar terms specifically include, but are not
                  limited to, MCIm, its officers, directors, employees, agents,
                  representatives, attorneys, contractors, subcontractors, and
                  other persons or entities performing services at the request
                  of or as directed by MCIm and their respective officers,
                  directors, employees, agents, and representatives.

                  1.1.22  PERSON ACTING ON BELLSOUTH'S BEHALF. The terms "person
                  acting on BellSouth's behalf," "personnel performing work on
                  BellSouth's behalf," and similar terms include both natural
                  persons and firms and ventures of every type, including but
                  not limited to corporations, partnerships, limited liability
                  companies, sole proprietorships, and joint ventures. The terms
                  "person acting on BellSouth's behalf," "personnel performing
                  work on BellSouth's behalf," and similar terms specifically
                  include, but are not limited to, BellSouth, its officers,
                  directors, employees, agents, representatives, attorneys,
                  contractors, subcontractors, and other persons or entities
                  performing services at the request or on behalf of BellSouth
                  and their respective officers, directors, employees, agents,
                  and representatives.

                  1.1.23  POLE. The term "pole" refers to both utility poles and
                  anchors but only to those utility poles and anchors owned or
                  controlled by BellSouth, and does not include utility poles or
                  anchors with respect to which BellSouth has no legal authority
                  to permit attachments by other persons or entities.

                  1.1.24  POLE ATTACHMENT ACT. The terms "Pole Attachment Act"
                  and "Pole Attachment Act of 1978" refer to those provisions of
                  the Communications Act of 1934, as amended, now codified as 47
                  U.S.C. ' 224.

                  1.1.25  PRELICENSE SURVEY. The term "prelicense survey" refers
                  to all work and activities performed or to be performed to
                  determine whether there is adequate capacity on a pole or in a
                  conduit or conduit system (including manholes and handholes)
                  to accommodate MCIm's facilities and to determine what
                  make-ready work, if any, is required to prepare the pole,
                  conduit or conduit system to accommodate MCIm's facilities.

                                                               Attachment VI - 4
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  1.1.26  RIGHT OF WAY (ROW). The term "right of way" refers to
                  the right to use the land or other property of another party
                  to place poles, conduits, cables, other structures and
                  equipment, or to provide passage to access such structures and
                  equipment. A Right of Way may run under, on, or above public
                  or private property (including air space above public or
                  private property) and may include the right to use discrete
                  space in buildings, building complexes, or other locations.

                  1.1.27  SHEATH. The term "sheath" refers to a single outer
                  covering containing communications wires, fibers, or other
                  communications media.

                  1.1.28  SPARE CAPACITY. The term "spare capacity" refers to
                  any pole attachment space, conduit, duct or inner-duct not
                  currently assigned or subject to a pending application for
                  attachment/occupancy. Spare capactiy does not include an
                  inner-duct (not to exceed one inner -duct per party) reserved
                  by BellSouth, MCIm, or a third party for maintenance, repair,
                  or emergency restoration.

                  1.1.29  STATE. When capitalized, the term "State" (as used in
                  terms such as "this State") refers to the State of
                  Mississippi.

                  1.1.30  THIRD PARTY. The terms "third party" and "third
                  parties" refer to persons and entities other than MCIm and
                  BellSouth. Use of the term "third party" does not signify that
                  any such person or entity is a party to this Agreement or has
                  any contractual rights hereunder.

         1.2      SCOPE OF ATTACHMENT

                  1.2.1   SCOPE OF ATTACHMENT. BellSouth shall provide MCIm with
                  equal and nondiscriminatory access to pole space, conduits,
                  ducts, and rights-of-way on terms and conditions equal to
                  those provided by BellSouth to itself or to any other
                  telecommunications service provider. Further, BellSouth shall
                  not withhold or delay assignment of such facilities to MCIm
                  because of the potential or forecasted needs of itself or
                  other parties.

                  1.2.2   ATTACHMENTS AND OCCUPANCIES AUTHORIZED BY THIS
                  ATTACHMENT. BellSouth shall issue one or more licenses to MCIm
                  authorizing MCIm to attach facilities to BellSouth's owned or
                  controlled poles and to place facilities within BellSouth's
                  owned or controlled conduits, ducts or rights-of-way under the
                  terms and

                                                               Attachment VI - 5
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  conditions set forth in this Attachment and the
                  Telecommunications Act of 1996.

                          1.2.2.1   Unless otherwise provided herein, authority
                          to attach facilities to BellSouth's owned or
                          controlled poles, to place facilities within
                          BellSouth's owned or controlled conduits, ducts or
                          rights-of-way shall be granted only in individual
                          licenses granted under this Attachment and the
                          placement or use of such facilities shall be
                          determined in accordance with such licenses and
                          procedures established in this Attachment.

                          1.2.2.2   MCIm agrees that its attachment of
                          facilities to BellSouth's owned or controlled poles,
                          occupancy of BellSouth's owned or controlled
                          conduits, ducts or rights-of-way shall take place
                          pursuant to the licensing procedures set forth
                          herein, and BellSouth agrees that it shall not
                          unreasonably withhold or delay issuance of such
                          licenses.

                  1.2.3   LICENSES. Subject to the terms and conditions set
                  forth in this Attachment, BellSouth shall issue to MCIm one or
                  more licenses authorizing MCIm to place or attach facilities
                  in or to specified poles, conduits, ducts or rights-of-way
                  owned or controlled by BellSouth located within this State on
                  a first come, first served basis. If BellSouth determines that
                  the pole, conduit or duct space specifically requested by MCIm
                  is necessary to meet BellSouth's present needs, or is
                  licensed by BellSouth to another licensee, or is otherwise
                  unavailable based on engineering concerns, BellSouth shall
                  have the right to designate the particular duct(s) to be
                  occupied, the location and manner in which MCIm's facilities
                  will enter and exit BellSouth's conduit system and the
                  specific location and manner of installation for any
                  associated equipment which is permitted by BellSouth to occupy
                  the conduit system, provided that BellSouth shall provide
                  written notice to MCIm within a reasonable time specifying in
                  detail the reasons for denying MCIm's request. If MCIm
                  disagrees with BellSouth's determination, the matter may be
                  submitted to the Alternative Dispute Resolution Process
                  described in Part A of this Agreement.

                  1.2.4   ACCESS AND USE OF RIGHTS-OF-WAY. BellSouth
                  acknowledges that it is required by the Telecommunications Act
                  of 1996 to afford MCIm access to and use of all associated
                  rights-of-way to any sites where BellSouth's owned or
                  controlled poles, manholes, conduits, ducts or other parts of
                  BellSouth's owned or controlled conduit systems are located
                  and any other owned or controlled ROW.

                                                               Attachment VI - 6
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          1.2.4.1   BellSouth shall provide MCIm with access to
                          and use of such rights-of-way to the same extent and
                          for the same purposes that BellSouth may access or
                          use such rights-of-way, including but not limited to
                          access for ingress, egress or other access and to
                          construct, utilize, maintain, modify, and remove
                          facilities for which pole attachment, conduit
                          occupancy, or ROW use licenses have been issued,
                          provided that any agreement with a third party under
                          which BellSouth holds such rights expressly or
                          impliedly grants BellSouth the right to provide such
                          rights to others.

                          1.2.4.2   Where BellSouth notifies MCIm that a
                          BellSouth agreement with a third party does not
                          expressly or impliedly grant BellSouth the ability to
                          provide such access and use rights to others, upon
                          MCIm's request, BellSouth will use its best efforts
                          to obtain the owner's consent and to otherwise
                          secure such rights for MCIm. MCIm agrees to reimburse
                          BellSouth for the reasonable and demonstrable costs
                          incurred by BellSouth in obtaining such rights for
                          MCIm.

                          1.2.4.3   In cases where a third party agreement does
                          not grant BellSouth the right to provide access and
                          use rights to others as contemplated in 1.2.4.1 and
                          BellSouth, despite its best efforts, is unable to
                          secure such access and use rights for MCIm in
                          accordance with 1.2.4.2, or, in the case where MCIm
                          elects not to invoke its rights under 1.2.4.1 or
                          1.2.4.2, MCIm shall be responsible for obtaining such
                          permission to access and use such rights-of-way.
                          BellSouth shall cooperate with MCIm in obtaining such
                          permission and shall not prevent or delay any third
                          party assignment of ROWs to MCIm.

                          1.2.4.4   Where BellSouth has any ownership or
                          rights-of-way to buildings or building complexes, or
                          within buildings or building complexes, BellSouth
                          shall offer to MCIm through a license or other
                          agreement:

                                    1.2.4.4.1   The right to use any available
                                    space owned or controlled by BellSouth in
                                    the building or building complex to install
                                    MCIm equipment and facilities; and

                                    1.2.4.4.2   Ingress and egress to such
                                    space.

                  1.2.5   Except to the extent necessary to meet the
                  requirements of the Telecommunications Act of 1996, neither
                  this

                                                               Attachment VI - 7
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  Attachment nor any license granted hereunder shall constitute
                  a conveyance or assignment of any of either party's rights to
                  use any public or private rights-of-way, and nothing contained
                  in this Attachment or in any license granted hereunder shall
                  be construed as conferring on one party any right to interfere
                  with the other party's access to any such public or private
                  rights-of-way.

                  1.2.6   NO EFFECT ON BELLSOUTH'S RIGHT TO CONVEY PROPERTY.
                  Nothing contained in this Attachment or in any license issued
                  hereunder shall in any way affect the right of BellSouth to
                  convey to any other person or entity any interest in real or
                  personal property, including any poles, conduit or ducts to or
                  in which MCIm has attached or placed facilities pursuant to
                  licenses issued under this Section; provided, however, that
                  BellSouth shall give MCIm reasonable advance written notice of
                  such intent to convey.

                  1.2.7   NO EFFECT ON BELLSOUTH'S RIGHTS TO MANAGE ITS OWN
                  FACILITIES. This Attachment shall not be construed as limiting
                  or interfering with BellSouth's rights set forth below, except
                  to the extent expressly provided by the provisions of this
                  Attachment or licenses issued hereunder or by the
                  Telecommunications Act of 1996 or other applicable laws, rules
                  or regulations:

                          1.2.7.1   To locate, relocate, move, replace, modify,
                          maintain, and operate BellSouth's own facilities
                          within BellSouth's conduits, ducts or rights-of way
                          or any of BellSouth's facilities attached to
                          BellSouth's poles at any time and in any reasonable
                          manner which BellSouth deems appropriate to serve its
                          customers, avail itself of new business
                          opportunities, or otherwise meet its business needs;
                          or

                          1.2.7.2   To enter into new agreements or arrangements
                          with other persons or entities permitting them to
                          attach or place their facilities to or in BellSouth's
                          poles, conduits or ducts; provided, however, that
                          such relocations, moves, replacements, modifications,
                          maintenance and operations or new agreements or
                          arrangements shall not substantially interfere with
                          MCIm's pole attachment, conduit occupancy or ROW use,
                          rights provided by licenses Issued pursuant to this
                          Attachment.

                  1.2.8   NO EFFECT ON MCIM'S RIGHTS TO MANAGE ITS OWN
                  FACILITIES. This Attachment shall not be construed as limiting
                  or

                                                               Attachment VI - 8
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  interfering with MCIm's rights set forth below, except to the
                  extent expressly provided by the provisions of this Attachment
                  or licenses issued hereunder or by the Telecommunications Act
                  of 1996 or other applicable laws, rules or regulations:

                          1.2.8.1   To locate, relocate, move, replace, modify,
                          maintain, and operate its own facilities within
                          BellSouth's conduits, ducts or rights-of-way or its
                          facilities attached to BellSouth's poles at any time
                          and in any reasonable manner which MCIm deems
                          appropriate to serve its customers, avail itself of
                          new business opportunities, or otherwise meet its
                          business needs; or

                          1.2.8.2   To enter into new agreements or arrangements
                          with other persons or entities permitting MCIm to
                          attach or place its facilities to or in such other
                          persons' or entities' poles, conduits or ducts, or
                          rights-of-way; provided, however, that such
                          relocations, moves, replacements, modifications,
                          maintenance and operations or new agreements or
                          arrangements shall not conflict with MCIm's
                          obligations under licenses issued pursuant to this
                          Attachment.

                  1.2.9   NO RIGHT TO INTERFERE WITH FACILITIES OF OTHERS. The
                  provisions of this Attachment or any license issued hereunder
                  shall not be construed as authorizing either party to this
                  Attachment to rearrange or interfere in any way with any of
                  the other party's facilities, with the facilities of other
                  persons or entities, or with the use of or access to such
                  facilities by such other party or such other persons or
                  entities, except to the extent expressly provided by the
                  provisions of this Attachment or any license issued hereunder
                  or by the Telecommunications Act of 1996 or other applicable
                  laws, rules or regulations.

                          1.2.9.1   MCIm acknowledges that the facilities of
                          persons or entities other than BellSouth and MCIm may
                          be attached to or occupy BellSouth's poles, conduits,
                          ducts and rights-of-way.

                          1.2.9.2   BellSouth shall not attach, or give
                          permission to any third parties to attach facilities
                          to, existing MCIm facilities without MCIm's prior
                          written consent. If BellSouth becomes aware of any
                          such unauthorized attachment to MCIm facilities,
                          BellSouth shall use its best efforts to rectify the
                          situation as soon as practicable.

                          1.2.9.3   With respect to facilities occupied by MCIm
                          or

                                                               Attachment VI - 9
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          the subject of an application for attachment by MCIm,
                          BellSouth will give to MCIm 60 days' written notice
                          for conduit extensions or reinforcements, 60 days'
                          written notice for pole line extensions, 60 days'
                          written notice for pole replacements, and 60 days'
                          written notice of BellSouth's intention to
                          construct, reconstruct, expand or place such
                          facilities or of BellSouth's intention not to
                          maintain or use any existing facility and, in the
                          case of an existing facility which BellSouth elects
                          not to maintain or use, BellSouth will grant to MCIm
                          a right to maintain and use such facility. If an
                          emergency or provision or an applicable joint use
                          agreement requires BellSouth to construct,
                          reconstruct, expand or replace poles, conduits or
                          ducts occupied by MCIm or the subject of an
                          application for attachment by MCIm, BellSouth will
                          notify MCIm as soon as reasonably practicable of such
                          proposed construction, reconstruction, expansion or
                          replacement to enable MCIm, if it so desires, to
                          request that a pole, conduit or duct of greater
                          height or capacity be utilized to accommodate an
                          anticipated facility need of MCIm.

                          1.2.9.4   At MCIm's expense, BellSouth shall remove
                          any retired cable from conduit systems to allow for
                          the efficient use of conduit space within a
                          reasonable period of time.

                          1.2.9.5   BellSouth shall allow MCIm for itself, or in
                          conjunction with other telecommunications carriers,
                          to reserve spares and space for maintenance and
                          emergency purposes in the same manner and for the
                          same period as it reserves such spares and space for
                          itself. Where a separate duct is not feasible for
                          space or other reasons, BellSouth shall make the
                          existing one available on a basis that does not
                          discriminate between itself and MCIm.

                  1.2.10  ASSIGNMENT OF SPACE. Assignment of space on poles, in
                  conduits or ducts and within ROWs will be granted by BellSouth
                  on an equal basis to BellSouth, MCIm and other
                  telecommunication service providers.

         1.3      REQUIREMENTS AND SPECIFICATIONS

                  1.3.1   PUBLISHED STANDARDS INCORPORATED IN THIS ATTACHMENT BY
                  REFERENCE. MCIm agrees that its facilities shall be placed,

                                                              Attachment VI - 10
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  constructed, maintained, repaired, and removed in accordance
                  with current (as of the date when such work is performed)
                  editions of the following publications, each of which is
                  incorporated by reference as part of this Attachment:

                          1.3.1.1   The Blue Book Manual of Construction
                          Procedures, Special Report SR-TAP-001421, published
                          by Bell Communications Research, Inc. ("Bellcore"),
                          and sometimes referred to as the "Blue Book";

                          1.3.1.2   The National Electrical Code (NEC); and

                          1.3.1.3   The National Electrical Safety Code (NESC).

                  1.3.2   CHANGES IN PUBLISHED STANDARDS. MCIm agrees to
                  rearrange its facilities in accordance with changes in the
                  standards published in the publications specified in Section
                  1.3 of this Attachment if required by law to do so or upon the
                  mutual agreement of the parties.

                  1.3.3   ADDITIONAL ELECTRICAL DESIGN SPECIFICATIONS. MCIm
                  agrees that, in addition to specifications and requirements
                  referred to in Articles 1.3.1-1.3.2 above, MCIm's facilities
                  placed in BellSouth's conduit system shall meet all of the
                  following electrical design specifications:

                          1.3.3.1   No facility shall be placed in BellSouth's
                          conduit system in violation of FCC regulations.

                          1.3.3.2   MCIm's facilities placed in BellSouth's
                          conduit system shall not be designed to use the earth
                          as the sole conductor for any part of MCIm's
                          circuits.

                          1.3.3.3   MCIm's facilities carrying more than 50
                          volts AC (rms) to ground or 135 volts DC to ground
                          shall be enclosed in an effectively grounded sheath
                          or shield.

                          1.3.3.4   No coaxial cable of MCIm shall occupy a
                          conduit system containing BellSouth's cable unless
                          such cable of MCIm meets the voltage limitations of
                          Article 820 of the National Electrical Code.

                          1.3.3.5   MCIm's coaxial cable may carry continuous DC
                          voltages up to 1800 volts to ground where the
                          conductor current will not exceed one-half amperes
                          and where such cable has two separate grounded metal
                          sheaths or shields and a suitable insulating jacket
                          over the outer sheath or shield. The power supply
                          shall be so designed and

                                                              Attachment VI - 11
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          maintained that the total current carried over the
                          outer sheath shall not exceed 200 micro amperes under
                          normal conditions. Conditions which would increase
                          the current over this level shall be cleared
                          promptly.

                          1.3.3.6   Neither party shall circumvent the other
                          party's corrosion mitigation measures. Each party's
                          new facilities shall be compatible with the other
                          party's facilities so as not to damage any facilities
                          of the other party by corrosion or other chemical
                          reaction.

                  1.3.4   ADDITIONAL PHYSICAL DESIGN SPECIFICATIONS. MCIm's
                  facilities placed in BellSouth's conduit system must meet all
                  of the following physical design specifications:

                          1.3.4.1   Cables bound or wrapped with cloth or having
                          any kind of fibrous coverings or impregnated with an
                          adhesive material shall not be placed in BellSouth's
                          conduit or ducts.

                          1.3.4.2   The integrity of BellSouth's conduit system
                          and overall safety of BellSouth's personnel and other
                          personnel working in BellSouth's conduit system
                          requires that "dielectric cable" be required when
                          MCIm's cable facility utilizes an alternative duct or
                          route that is shared in the same trench by any
                          current carrying facility of a power utility.

                          1.3.4.3   New construction splices in MCIm's fiber
                          optic and twisted pair cables shall be located in
                          manholes, pull boxes or handholes.

                  1.3.5   ADDITIONAL SPECIFICATIONS APPLICABLE TO CONNECTIONS.
                  The following specifications apply to connections of MCIm's
                  conduit to BellSouth's conduit system:

                          1.3.5.1   MCIm will be permitted to connect its
                          conduit or duct only at the point of a BellSouth
                          manhole. No attachment will be made by entering or
                          breaking into conduit between manholes. All necessary
                          work to install MCIm facilities will be performed by
                          MCIm or its contractor at MCIm's expense. In no
                          event shall MCIm or its contractor "core bore" or
                          make any other modification to BellSouth manhole(s)
                          without the prior written approval of BellSouth,
                          which approval will not be unreasonably delayed or
                          withheld.

                                                              Attachment VI - 12
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          1.3.5.2   BellSouth may monitor, at MCIm's expense,
                          the entrance and exit of MCIm's facilities into
                          BellSouth's manholes and the placement of MCIm's
                          facilities in BellSouth's manholes.

                          1.3.5.3   If MCIm constructs or utilizes a duct
                          connected to BellSouth's manhole, the duct and all
                          connections between that duct and BellSouth's manhole
                          shall be sealed, to the extent practicable, to
                          prevent the entry of gases or liquids into
                          BellSouth's conduit system. If MCIm's duct enters a
                          building, it shall also be sealed where it enters the
                          building and at all other locations necessary to
                          prevent the entry of gases and liquids from the
                          building into BellSouth's conduit system.

                  1.3.6   REQUIREMENTS RELATING TO PERSONNEL, EQUIPMENT,
                  MATERIAL, AND CONSTRUCTION PROCEDURES GENERALLY. Duct
                  clearing, rodding or modifications required to grant MCIm
                  access to BellSouth's conduit systems may be performed by
                  BellSouth at MCIm's expense at charges which represent
                  BellSouth's actual costs. Alternatively (at MCIm's option)
                  such work may be performed by MCIm or a contractor provided
                  that the entity performing the work demonstrates compliance
                  with BellSouth certification requirements, which certification
                  requirements shall be consistent with FCC rules. The parties
                  acknowledge that MCIm, its contractors, and other persons
                  acting on MCIm's behalf will perform work for MCIm (e.g.,
                  splicing MCIm's facilities) within BellSouth's conduit system.
                  MCIm represents and warrants that neither MCIm nor any person
                  acting on MCIm's behalf shall permit any person to climb or
                  work on or in any of BellSouth's poles or to enter BellSouth's
                  manholes or work within BellSouth's conduit system unless such
                  person has the training, skill, and experience required to
                  recognize potentially dangerous conditions relating to pole or
                  the conduit systems and to perform the work safely.

                          1.3.6.1   MCIm's facilities within BellSouth's conduit
                          system shall be constructed, placed, rearranged,
                          modified, and removed upon receipt of a license
                          specified in 1.5.1. However, no such license will be
                          required for the inspection, maintenance, repair or
                          non-physical modifications of MCIm's facilities.

                          1.3.6.2   "Rodding" or clearing of ducts in
                          BellSouth's conduit system shall be done only when
                          specific authorization for such work has been
                          obtained in advance from BellSouth, which
                          authorization shall not be

                                                              Attachment VI - 13
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          unreasonably delayed or withheld by BellSouth. The
                          parties agree that such rodding or clearing shall be
                          performed according to existing industry standards
                          and practices. MCIm may perform such work itself or
                          may contract with BellSouth for performance of such
                          work or (at MCIm's option) with a contractor
                          provided that the entity performing the work
                          demonstrates compliance with BellSouth certification
                          requirements which certification requirements shall
                          be consistent with FCC rules.

                          1.3.6.3   Personnel performing work on BellSouth's or
                          MCIm's behalf in BellSouth's conduit system shall not
                          climb on, step on, or otherwise disturb the other
                          party's or any third party's cables, air pipes,
                          equipment, or other facilities located in any manhole
                          or other part of BellSouth's conduit system.

                          1.3.6.4   Personnel performing work on BellSouth's or
                          MCIm's behalf within BellSouth's conduit system
                          (including any manhole) shall, upon completing their
                          work, make reasonable efforts to remove all tools,
                          unused materials, wire clippings, cable sheathing and
                          other materials brought by them to the work site.

                          1.3.6.5   All of MCIm's facilities shall be firmly
                          secured and supported in accordance with Bellcore and
                          industry standards.

                          1.3.6.6   MCIm's facilities shall be plainly
                          identified with MCIm's name in each manhole with a
                          firmly affixed permanent tag that meets standards set
                          by BellSouth for its own facilities.

                          1.3.6.7   Manhole pumping and purging required in
                          order to allow MCIm's work operations to proceed
                          shall be performed by MCIm or its contractor in
                          compliance with BellSouth Practice Sec.
                          620-145-011BT, "Manhole Contaminants, Water, Sediment
                          or Debris Removal and Reporting Procedures," and any
                          amendments, revisions or supplements thereto and in
                          compliance with all regulations and standards
                          established by the United States Environmental
                          Protection Agency and by any applicable state or
                          local environmental regulators.

                          1.3.6.8   Planks or other types of platforms shall not
                          be

                                                              Attachment VI - 14
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          installed using cables, pipes or other equipment as a
                          means of support. Platforms shall be supported only
                          by cable racks.

                          1.3.6.9   Any leak detection liquid or device used by
                          MCIm or personnel performing work on MCIm's
                          facilities within BellSouth's conduit system shall be
                          of a type approved by BellSouth or Bellcore.

                          1.3.6.10  When MCIm or personnel performing work on
                          MCIm's behalf are working within or in the vicinity
                          of any part of BellSouth's poles or conduit system
                          which is located within, under, over, or adjacent to
                          streets, highways, alleys or other traveled
                          rights-of-way, MCIm and all personnel performing work
                          on MCIm's behalf shall follow procedures which MCIm
                          deems appropriate for the protection of persons and
                          property. MCIm shall be responsible, at all times,
                          for determining and implementing the specific steps
                          required to protect persons and property at the site.
                          MCIm will provide all traffic control and warning
                          devices required to protect pedestrian and vehicular
                          traffic, workers and property from danger. MCIm has
                          sole responsibility for the safety of all personnel
                          performing work on MCIm's behalf, for the safety of
                          bystanders, and for insuring that all operations
                          conform to current OSHA regulations and all other
                          governmental rules, ordinances or statutes. BellSouth
                          reserves the right to suspend MCIm's activities on,
                          in or in the vicinity of BellSouth's poles or conduit
                          system if, in BellSouth's reasonable judgment, any
                          hazardous condition arises due to the activity
                          (including both acts and omissions) of MCIm or any
                          personnel performing work on MCIm's behalf, which
                          suspension shall cease when the condition has been
                          rectified.

                          1.3.6.11  Except for protective screens, no temporary
                          cover shall be placed by MCIm or personnel performing
                          work on MCIm's behalf over an open manhole unless it
                          is at least four feet above the surface level of the
                          manhole opening.

                          1.3.6.12  Smoking or the use of any open flame is
                          prohibited in BellSouth's manholes, in any other
                          portion of BellSouth's conduit system, or within 10
                          feet of any open manhole entrance; provided that this
                          provision will not prohibit the use of spark
                          producing tools such as electric drills, fusion
                          splicers, etc.

                          1.3.6.13  Artificial lighting, when required, will be

                                                              Attachment VI - 15
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          provided by MCIm. Only explosion-proof lighting
                          fixtures shall be used.

                          1.3.6.14  Neither MCIm nor personnel performing work
                          on MCIm's behalf shall allow any combustible gas,
                          vapor, liquid, or material to accumulate in
                          BellSouth's conduit system (including any manhole)
                          during work operations performed within or in the
                          vicinity of BellSouth's conduit system.

                          1.3.6.15  MCIm will abide by any laws, regulations or
                          ordinances regarding the use of spark producing
                          tools, equipment or devices in BellSouth's manholes,
                          in any other portions of BellSouth's conduit system,
                          or within 10 feet of any open manhole opening. This
                          includes, but is not limited to, such tools as
                          electric drills and hammers, meggers, breakdown sets,
                          induction sets, and the like.

                  1.3.7   OPENING OF MANHOLES. The following requirements apply
                  to the opening of BellSouth's manholes and the authority of
                  BellSouth personnel present when work on MCIm's behalf is
                  being performed within or in the vicinity of BellSouth's
                  conduit system.

                          1.3.7.1   BellSouth's manholes shall be opened only as
                          permitted by BellSouth's authorized employees or
                          agents, which permission shall not be unreasonably
                          denied or delayed.

                          1.3.7.2   MCIm shall notify BellSouth forty-eight (48)
                          hours in advance of any routine work operation
                          requiring entry into any of BellSouth' s manholes.

                          1.3.7.3   MCIm shall be responsible for obtaining any
                          necessary authorization from appropriate authorities
                          to open manholes for conduit work operations therein.

                          1.3.7.4   BellSouth's authorized employee or agent
                          shall not direct or control the conduct of MCIm's
                          work at the work site. The presence of BellSouth's
                          authorized employee or agent at the work site shall
                          not relieve MCIm or personnel performing work on
                          MCIm's behalf of their responsibility to conduct all
                          work operations within BellSouth's conduit system in
                          a safe and workmanlike manner.

                          1.3.7.5   Although BellSouth's authorized employee or
                          agent shall not direct or control the conduct of
                          MCIm's work at the work site, BellSouth's employee or
                          agent shall have

                                                              Attachment VI - 16
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          the authority to suspend MCIm's work operations
                          within BellSouth's conduit system if, in the
                          reasonable discretion of such BellSouth employee or
                          agent, it appears that any hazardous conditions arise
                          or any unsafe practices are being followed by MCIm or
                          personnel performing work on MCIm's behalf.

                  1.3.8   OSHA COMPLIANCE: NOTICE TO BELLSOUTH OF UNSAFE
                  CONDITIONS. MCIm agrees that:

                          1.3.8.1   Its facilities shall be constructed, placed,
                          maintained, repaired, and removed in accordance with
                          the Occupational Safety and Health Act (OSHA) and all
                          rules and regulations promulgated thereunder;

                          1.3.8.2   All persons acting on MCIm's behalf,
                          including but not limited to MCIm's employees,
                          agents, contractors, and subcontractors shall, when
                          working on or within BellSouth's poles or conduit
                          system, comply with OSHA and all rules and
                          regulations thereunder;

                          1.3.8.3   MCIm shall establish appropriate procedures
                          and controls to assure compliance with all
                          requirements of this Attachment; and

                          1.3.8.4   MCIm (and any person acting on MCIm's
                          behalf) may report unsafe conditions on, in or in the
                          vicinity of BellSouth's poles or conduit system to
                          BellSouth.

                  1.3.9   COMPLIANCE WITH ENVIRONMENTAL LAWS AND REGULATIONS.
                  MCIm acknowledges that, from time to time, environmental
                  contaminants may enter BellSouth's conduit system and
                  accumulate in manholes or other conduit facilities and that
                  certain conduits (transite) are constructed with
                  asbestos-containing materials. If BellSouth has knowledge of
                  the presence of such contaminants in a conduit for which MCIm
                  has applied for or holds a license, BellSouth will promptly
                  notify MCIm of such fact. Notwithstanding any of BellSouth's
                  notification requirements in this Agreement, MCIm acknowledges
                  that some of BellSouth's conduit is fabricated from
                  asbestos-containing materials. Such conduit is generally
                  marked with a designation of "C Fiber Cement Conduit, "
                  "Transite," or "Johns-Manville." Unless sampling or
                  manufacturer's certification proves otherwise, MCIm will
                  presume that all conduit not fabricated of plastic, tile, or
                  wood is asbestos-containing and will handle it pursuant to all
                  applicable regulations relating to worker safety and
                  protection of the environment. BellSouth makes no
                  representations to MCIm or personnel performing work on MCIm's
                  behalf that BellSouth's conduit system or any specific

                                                              Attachment VI - 17
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  portions thereof will be free from environmental contaminants
                  at any particular time. The acknowledgments and
                  representations set forth in the two preceding sentences are
                  not intended to relieve BellSouth of any liability which it
                  would otherwise have under applicable law for the presence of
                  environmental contaminants in its conduit facilities. MCIm
                  agrees to comply with the following provisions relating to
                  compliance with environmental laws and regulations:

                          1.3.9.1   MCIm's facilities shall be constructed,
                          placed, maintained, repaired, and removed in
                          accordance with all applicable federal, state, and
                          local environmental statutes, ordinances, rules,
                          regulations, and other laws, including but not
                          limited to the Resource Conservation and Recovery Act
                          (42 U.S.C. ss. 9601 et seq.), the Toxic Substance
                          Control Act (15 U.S.C. ss. 2601-2629), the Clean
                          Water Act (33 U.S.C. ss. 1251 et seq.), and the Safe
                          Drinking Water Act (42 U.S.C. ss. 300f-300j).

                          1.3.9.2   All persons acting on MCIm's behalf,
                          including but not limited to MCIm's employees,
                          agents, contractors, and subcontractors, shall, when
                          working on, within or in the vicinity of BellSouth's
                          poles or conduit system, comply with all applicable
                          federal, state, and local environmental laws,
                          including but not limited to all environmental
                          statutes, ordinances, rules, and regulations.

                          1.3.9.3   MCIm shall establish appropriate procedures
                          and controls to assure compliance with all
                          requirements of this section.

                          1.3.9.4   MCIm and all personnel performing work on
                          MCIm's behalf shall comply with such standards and
                          practices as BellSouth and MCIm may from time to time
                          mutually agree to adopt to comply with environmental
                          laws and regulations including, without limitation,
                          BellSouth Practice Sec. 620-145-011BT, "Manhole
                          Contaminants, Water, Sediment or Debris Removal and
                          Reporting Procedures". Pursuant to this practice,
                          neither MCIm nor BellSouth nor personnel performing
                          work on either party's behalf shall discharge water
                          or any other substance from any BellSouth manhole or
                          other conduit facility onto public or private
                          property, including any storm water drainage system,
                          without first testing such water or substance for
                          contaminants in accordance with mutually agreed
                          standards

                                                              Attachment VI - 18
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          and practices and determining that such discharge
                          would not violate any environmental law, create any
                          environmental risk or hazard, or damage the property
                          of any person. Proper handling and disposal of any
                          waste material from a BellSouth manhole by MCIm or
                          its contractor shall be the responsibility of MCIm.
                          No such waste material shall be deposited on
                          BellSouth premises for storage or disposal.

                  1.3.10  COMPLIANCE WITH OTHER GOVERNMENTAL REQUIREMENTS. MCIm
                  agrees that its facilities attached to BellSouth's facilities
                  shall be constructed, placed, maintained, and removed in
                  accordance with the ordinances, rules, and regulations of any
                  governing body having jurisdiction of the subject matter. MCIm
                  shall comply with all applicable statutes, ordinances, rules,
                  regulations and other laws requiring the marking and lighting
                  of aerial wires, cables and other structures to ensure that
                  such wires, cables and structures are not a hazard to
                  aeronautical navigation. MCIm shall establish appropriate
                  procedures and controls to assure such compliance.

                  1.3.11  DIFFERENCES IN STANDARDS OR SPECIFICATIONS. To the
                  extent that there may be differences in any applicable
                  standards or specifications referred to in this Section 1.3,
                  the most stringent standard or specification shall apply.

                  1.3.12  MCIM SOLELY RESPONSIBLE FOR THE CONDITION OF ITS
                  FACILITIES. MCIm shall be responsible at all times for the
                  condition of its facilities and its compliance with the
                  requirements, specifications, rules, regulations, ordinances,
                  and laws specified in 1.3.1-1.3.11 above. In this regard,
                  BellSouth shall have no duty to MCIm to inspect or monitor the
                  condition of MCIm's facilities (including but not limited to
                  splices and other facilities connections) located within
                  BellSouth's conduit and ducts or any attachment of MCIm's
                  facilities to BellSouth's poles, anchors, anchor/guy strands
                  or other pole facilities. BellSouth may, however, conduct such
                  inspections and audits of its poles and conduit system as
                  BellSouth determines reasonable or necessary. Such inspection
                  and audits shall be conducted at BellSouth' s expense with the
                  exception of (1) follow-up inspection to confirm remedial
                  action after an observed MCIm violation of the requirements of
                  this Agreement; and (2) inspection of MCIm facilities in
                  compliance with a specific mandate of appropriate governmental
                  authority for which inspections the cost shall be borne by
                  MCIm. Either party may audit the other party's compliance with
                  the terms of this Section 1.3.12.

                  1.3.13 EFFICIENT USE OF CONDUIT. BellSouth will install inner-

                                                              Attachment VI - 19
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          ducts to increase duct space in existing conduit as
                          facilities permit. The full compliment of inner-ducts
                          will be installed which can be accommodated under
                          sound engineering principles. The number of
                          inner-ducts which can reasonably be installed will be
                          determined by BellSouth, pursuant to such engineering
                          principles.

         1.4      ADDITIONAL LEGAL REQUIREMENTS

                  1.4.1   Left Blank Intentionally

                          1.4.1.1   Licenses granted under this Attachment
                          authorize MCIm to place facilities in, or attach
                          facilities to, poles, conduits and ducts owned or
                          controlled by BellSouth but do not affect the rights
                          of landowners to control terms and conditions of
                          access to their property.

                          1.4.1.2   MCIm agrees that neither MCIm nor any
                          persons acting on MCIm's behalf, including but not
                          limited to MCIm's employees, agents, contractors, and
                          subcontractors, shall engage in any conduct which
                          damages public or private property in the vicinity of
                          BellSouth's poles or conduit system, interferes in
                          any way with the use or enjoyment of public or
                          private property except as expressly permitted by the
                          owner of such property, or creates a hazard or
                          nuisance on such property (including, but not limited
                          to, a hazard or nuisance resulting from any
                          abandonment or failure to remove MCIm's facilities or
                          any construction debris from the property, failure to
                          erect warning signs or barricades as may be necessary
                          to give notice to others of unsafe conditions on the
                          premises while work performed on MCIm's behalf is in
                          progress, or failure to restore the property to a
                          safe condition after such work has been completed).

                  1.4.2   REQUIRED PERMITS, CERTIFICATES AND LICENSES. MCIm
                  shall be responsible for obtaining any additional building
                  permits or certificates from governmental authorities
                  necessary to construct, operate, maintain and remove its
                  facilities on public or private property.

                          1.4.2.1   MCIm shall not attach or place its
                          facilities to or in BellSouth's poles, conduit or
                          duct located on any property for which it or
                          BellSouth has not first obtained all required
                          authorizations.

                          1.4.2.2   BellSouth shall have the right to request
                          evidence that all appropriate authorizations have
                          been obtained. However, such request shall not delay

                                                              Attachment VI - 20
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          BellSouth's prelicense survey work.

                  1.4.3   LAWFUL PURPOSES. All facilities placed by MCIm in
                  BellSouth's conduit and ducts or on BellSouth's poles, anchors
                  or anchor/guy strands must serve a lawful purpose and the uses
                  made of MCIm's facilities must comply with all applicable
                  federal, state, and local laws and with all federal, state,
                  and local regulatory rules, regulations, and requirements. In
                  this regard, MCIm shall not utilize any facilities occupying
                  or attached to BellSouth's conduits, ducts or poles for the
                  purpose of providing any services which it is not authorized
                  by law to provide or for the purpose of enabling any other
                  person or entity to provide any such services.

         1.5      FACILITIES AND LICENSES

                  1.5.1   LICENSES REQUIRED. Before placing any facilities in
                  BellSouth's conduits or ducts or attaching any facilities to
                  BellSouth's poles, anchors or anchor/guy strands, MCIm must
                  first apply for and receive a written license from BellSouth.
                  BellSouth shall not unreasonably deny or delay issuance of any
                  license and, in any event, BellSouth shall issue such license
                  within twenty (20) business days from (i) submission of the
                  license application if make-ready work is not required, or
                  (ii) completion of make-ready work, if make-ready work is
                  needed.

                  1.5.2   PROVISION OF RECORDS AND INFORMATION TO MCIM.

                          1.5.2.1   In order to obtain information regarding
                          facilities, MCIm shall make a written request to
                          BellSouth, identifying with reasonable specificity
                          the geographic area for which facilities are
                          required, the types and quantities of the required
                          facilities and the required in-service date. In
                          response to such request, BellSouth shall provide
                          MCIm with information regarding the types, quantity
                          and location (which may be provided by provision of
                          route maps and availability of BellSouth poles,
                          conduit and right-of-way located within the
                          geographic area specified by MCIm. Provision of
                          information under the terms of this section shall
                          include the right of MCIm employees or agents to
                          inspect and copy engineering records or drawings
                          which pertain to those facilities within the
                          geographic area identified in MCIm' s request. Such
                          inspection and copying shall be done at a time and
                          place mutually agreed upon by the parties.

                          1.5.2.2   Records will be available for inspection at
                          the applicable BellSouth Records Maintenance Center
                          (RMC) responsible for the state where the proposed
                          license is

                                                              Attachment VI - 21
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          located within (5) business days from the date
                          BellSouth receives the Inquiry Request. BellSouth
                          shall provide MCIm with a complete list of RMC
                          locations within ten (10) days of the Effective Date
                          of this Agreement. As an alternative, MCIm may
                          specify that copies of the records be forwarded
                          directly from the RMC to the MCIm SPOC, or other MCIm
                          designated recipient, within twenty (20) business
                          days from the date BellSouth receives the Inquiry
                          Request. MCIm may elect to be present at any field
                          based survey of facilities identified pursuant to
                          this paragraph and BellSouth shall provide MCIm at
                          least forty-eight (48) hours notice prior to
                          initiating such field survey. MCIm employees or
                          agents shall be permitted to enter BellSouth manholes
                          and inspect such structures to confirm usability
                          and/or evaluate condition of the structure(s) with at
                          least forty-eight (48) hours notice to BellSouth,
                          with a BellSouth representative present and at MCIm's
                          expense.

                  1.5.3   MAKE-READY WORK

                          1.5.3.1   If performed by BellSouth, make-ready work
                          to accommodate MCIm's facilities shall be included
                          in the normal work load schedule of BellSouth with
                          construction responsibilities in the geographic areas
                          where the relevant poles or conduit systems are
                          located and shall not be entitled to priority,
                          advancement, or preference over other work to be
                          performed by BellSouth in the ordinary course of
                          BellSouth's business.

                          1.5.3.2   If MCIm desires make-ready work to be
                          performed on an expedited basis and BellSouth agrees
                          to perform the work on such a basis, BellSouth shall
                          recalculate the estimated make-ready charges. If MCIm
                          accepts BellSouth's offer, MCIm shall pay such
                          additional charges.

                          1.5.3.3   All charges for make-ready work performed by
                          BellSouth are payable in advance, with the amount of
                          any such advance payment to be due within sixty (60)
                          days after receipt of an invoice from BellSouth.

                          1.5.3.4   In lieu of obtaining performance of
                          make-ready work by BellSouth, MCIm at its option may
                          perform the make-ready work itself or arrange for the
                          performance of such work by a contractor. The party
                          performing the work must be certified by BellSouth to
                          work on or in its facilities. Certification shall be
                          granted based upon reasonable and

                                                              Attachment VI - 22
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          customary criteria employed by BellSouth in the
                          selection of its own contract labor in accordance
                          with FCC rules. Notwithstanding any other provisions
                          of this Attachment, MCIm may not employ a contractor
                          to accomplish make-ready work if BellSouth is
                          likewise precluded from contractor selection under
                          the terms of an applicable joint use agreement.

                          1.5.3.5   BellSouth will issue a license to MCIm at
                          the time all make-ready work necessary to MCIm's
                          attachment or occupancy has been completed.

                  1.5.4   APPLICATION FORM AND FEES. To apply for a license
                  under this Attachment, MCIm shall submit to BellSouth two
                  signed copies of an Application and Conduit Occupancy License
                  form or an Application and Pole Attachment License form.
                  BellSouth will process license applications in the order in
                  which they are received; provided, however, that when MCIm has
                  multiple applications on file with BellSouth, MCIm may
                  designate its desired priority of completion of prelicense
                  surveys and make-ready work with respect to all such
                  applications.

                          1.5.4.1   Each application for a license under this
                          Attachment shall specify the proposed route of MCIm's
                          facilities and identify the conduits and ducts or
                          poles and pole facilities along the proposed route in
                          which MCIm desires to place or attach its facilities,
                          and describe the physical size, weight and jacket
                          material of the cable which MCIm desires to place in
                          each conduit or duct or the number and type of
                          cables, apparatus enclosures and other facilities
                          which MCIm desires to attach to each pole.

                          1.5.4.2   Each application for a license under this
                          Attachment shall be accompanied by a proposed (or
                          estimated) construction schedule containing the
                          information specified below in 1.8.1 of this
                          Attachment, and an indication of whether MCIm will,
                          at it's option, perform it's own make-ready work.

                          1.5.4.3   The parties agree to the establishment of a
                          joint task force, consisting of representatives of
                          MCIm and BellSouth, which will develop all procedures
                          necessary to effectuate the provisions of this
                          Section 1.5. Matters to be addressed by the joint
                          task force include, without limitation, the
                          development of time frames for BellSouth's provision
                          of record information and availability determinations
                          and for the processing of license applications; the
                          establishment of

                                                              Attachment VI - 23
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          guidelines to address the number of MCIm applications
                          which may be processed simultaneously by BellSouth;
                          and any other matters necessary to effectuate the
                          provisions of this Attachment. The parties agree to
                          negotiate in good faith to achieve agreement on all
                          matters presented to the joint task force and to
                          reduce said agreement to writing within sixty (60)
                          calendar days from the Effective Date of this
                          Agreement.

                  1.5.5   ASSIGNMENT OF CONDUIT, DUCT AND POLE SPACE. Within
                  twenty (20) business days of receipt of MCIm's application.
                  BellSouth shall approve the assignment of space for pole
                  attachment and conduit occupancy. If no make ready work is
                  required, such assignment shall include a granting of the
                  license. If make ready is to be performed by BellSouth, such
                  assignment shall remain in effect until make ready costs are
                  presented to MCIm and approval by MCIm pursuant to the
                  timeframes herein stated. If MCIm approves BellSouth's make
                  ready costs, MCIm shall have twelve (12) months from the date
                  of assignment or sixty (60) days after completion of make
                  ready by BellSouth, whichever time is later, to install its
                  facilities. If MCIm rejects BellSouth's costs for make ready,
                  but then elects to perform the make ready itself or through a
                  contractor or if MCIm elects from the time of application to
                  perform the make ready itself or through a contractor, MCIm
                  shall install its facilities within twelve (12) months from
                  the date of assignment. In the event MCIm does not install its
                  facilities within the time frames set out in this paragraph,
                  the assignment shall be void and such space shall become
                  available.

                  1.5.6   MULTIPLE CABLES, MULTIPLE SERVICES, LASHING OR PLACING
                  ADDITIONAL CABLES, AND REPLACEMENT OF FACILITIES. MCIm may
                  include multiple cables in a single license application and
                  multiple services (e.g., CATV and non-CATV services) may be
                  provided by MCIm in the same cable sheath. MCIm's lashing
                  additional cable to existing facilities of MCIm and placing
                  additional cables in conduits or ducts already occupied by
                  MCIm's facilities shall be permitted, and no additional fees
                  will be applied; provided, however, that if MCIm desires to
                  lash additional cable to existing facilities or place
                  additional cables in conduits or ducts which are already
                  occupied, or to replace existing facilities with new
                  facilities substantially different from those described in
                  licenses in effect, MCIm must apply for and acquire a new
                  license specifically describing the physical size, weight and
                  jacket material of the cable to be placed in BellSouth's
                  conduits and ducts or the physical size, weight, and jacket
                  type of cables and the size and weight of apparatus enclosures
                  and other facilities to be attached to BellSouth's poles.

                                                              Attachment VI - 24
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  1.5.7   SINGLE POINT OF CONTACT. Each party hereby designates
                  the employees named below as their single point of contact for
                  any and all purposes of this Attachment, including, but not
                  limited to, processing licenses and applications and providing
                  records and information. Each party may at any time designate
                  a new point of contact by giving written notice of such
                  change.

                            [Title of Single Point of Contact]
                            [Address, phone and fax]

                  1.5.8   Anything to the contrary herein notwithstanding,
                  notification of an emergency condition which poses an
                  immediate threat to life or property or substantially impairs
                  provisioning of BellSouth's service shall be reported to
                  BellSouth by contacting:

                            [BellSouth name]
                            [Address, phone and fax]

         1.6      PROCESSING OF APPLICATIONS (INCLUDING PRELICENSE SURVEYS AND
         FIELD INSPECTIONS)

                  1.6.1   MCIM'S PRIORITIES. When MCIm has multiple applications
                  on file with BellSouth, MCIm shall designate its desired
                  priority of completion of prelicense surveys and make-ready
                  work with respect to all such applications.

                  1.6.2   PRELICENSE SURVEY. After MCIm has submitted its
                  written application for a license, a prelicense survey
                  (including a field inspection) will be performed by either
                  party, in the company of a representative of the other party
                  as mutually agreed, to determine whether BellSouth's poles,
                  anchors and anchor/guy strands, or conduit system, in their
                  present condition, can accommodate MCIm's facilities, without
                  substantially interfering with the ability of BellSouth or any
                  other authorized person or entity to use or access the pole,
                  anchor or anchor/guy strand or any portion of BellSouth's
                  conduit system or facilities attached to BellSouth's pole or
                  placed within or connected to BellSouth's conduit system. If
                  MCIm gives its prior written consent in writing, the
                  determination of duct availability may include the "rodding"
                  of ducts at MCIm's expense.

                          1.6.2.1   The purpose of the prelicense survey is to
                          determine whether space is available for MCIm's
                          proposed attachments or whether MCIm's proposed
                          attachments to BellSouth's poles or occupancy of
                          BellSouth's conduit and

                                                              Attachment VI - 25
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          ducts will substantially interfere with use of
                          BellSouth's facilities by BellSouth and others with
                          facilities occupying, connected or attached to
                          BellSouth's pole or conduit system; and to provide
                          information to MCIm for its determination of whether
                          the pole, anchor, anchor/guy strand, conduit, duct,
                          or right-of-way is suitable for its use.

                          1.6.2.2   Based on information provided by BellSouth,
                          MCIm shall determine whether BellSouth's pole,
                          anchor, anchor/guy strand, conduit and duct
                          facilities are suitable to meet MCIm's needs.

                          1.6.2.3   BellSouth may not unreasonably refuse to
                          continue to process an application based on
                          BellSouth's determination that MCIm's proposed use of
                          BellSouth's facilities will not be in compliance
                          with applicable requirements, specifications, rules,
                          regulations, ordinances, and laws. MCIm shall be
                          responsible for making its own, independent
                          determination that its use of such facilities will be
                          in compliance with such requirements, specifications,
                          rules, regulations, ordinances and laws. MCIm
                          acknowledges that BellSouth is not explicitly or
                          implicitly warranting to MCIm that MCIm's proposed
                          use of BellSouth's facilities will be in compliance
                          with applicable requirements, specifications, rules,
                          regulations, ordinances, and laws.

                  1.6.3   ENVIRONMENTAL, HEALTH AND SAFETY INSPECTIONS. Within a
                  reasonable time period after MCIm has submitted its written
                  application for a license, BellSouth shall provide MCIm with
                  such information about environmental, health and safety
                  inspections that is equal to the information that (i)
                  BellSouth retains and provides for the use of its employees
                  who access rights of way, conduits and pole attachments, or
                  (ii) BellSouth is required to retain, pursuant to applicable
                  laws and regulations. Nothing in this Section 1.6.3 is
                  intended to create any additional liabilities that might
                  otherwise exist with respect to environmental, health and
                  safety inspections and to notices thereof.

                  1.6.4   ADMINISTRATIVE PROCESSING. The administrative
                  processing portion of the prelicense survey (which includes
                  without limitation processing the application, preparing
                  make-ready work orders, notifying joint users and other
                  persons and entities of work requirements and schedules,
                  coordinating the relocation/rearrangement of BellSouth and/or
                  other licensed facilities) will be performed by BellSouth at
                  MCIm's expense.

                                                              Attachment VI - 26
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  Anything to the contrary herein notwithstanding, BellSouth
                  shall bear no responsibility for the relocation, rearrangement
                  or removal of facilities used for the transmission or
                  distribution of electric power.

         1.7      ISSUANCE OF LICENSES

                  1.7.1   OBLIGATION TO ISSUE LICENSES. BellSouth shall issue a
                  license to MCIm pursuant to this section 1.7. BellSouth and
                  MCIm acknowledge that each application for a license shall be
                  evaluated on an individual basis. Nothing contained in this
                  Attachment shall be construed as abridging any independent
                  pole attachment rights or conduit or duct access rights which
                  MCIm may have under the provisions of any applicable federal
                  or state laws or regulations governing access to BellSouth's
                  poles, conduits and ducts, to the extent the same are not
                  inconsistent with the Telecommunications Act of 1996. Each
                  license issued hereunder shall be for an indefinite term,
                  subject to MCIm's compliance with the provisions applicable to
                  such license and further subject to MCIm's right to terminate
                  such license at any time for any reason upon at least thirty
                  (30) days' prior written notice.

                  1.7.2   ISSUANCE OF LICENSES WHEN NO MAKE-READY WORK IS
                  REQUIRED. If BellSouth determines that no make-ready work is
                  required,, BellSouth shall approve applications for pole
                  attachment and conduit occupancy licenses and issue such
                  licenses within twenty (20) business days of receipt of MCIm'
                  s application.

                  1.7.3   MULTIPLE APPLICATIONS. MCIm acknowledges that multiple
                  parties including BellSouth may seek to place their facilities
                  in BellSouth's conduit and ducts at or about the same time,
                  that the make-ready work required to prepare BellSouth's
                  facilities to accommodate multiple applicants may differ from
                  the make-ready work required to accommodate a single
                  applicant, that issues relating to the proper apportionment of
                  costs arise in multi-applicant situations that do not arise in
                  single-applicant situations, and that cooperation and
                  negotiations between all applicants and BellSouth may be
                  necessary to resolve disputes involving multiple applications
                  for permission to place facilities in/on the same pole,
                  conduit, duct, or right-of-way.

                          1.7.3.1   All applications will be processed on a
                          first-come, first served basis.

                  1.7.4   AGREEMENT TO PAY FOR ALL MAKE-READY WORK

                                                              Attachment VI - 27
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  COMPLETED. MCIm's submission of written authorization for
                  make-ready work shall also constitute MCIm's agreement to pay
                  additional cost-based charges, if any, for completed
                  make-ready work.

                  1.7.5   PAYMENTS TO OTHERS FOR EXPENSES INCURRED IN
                  TRANSFERRING OR ARRANGING THEIR FACILITIES. MCIm shall make
                  arrangements with the owners of other facilities located in or
                  connected to BellSouth's conduit system or attached to
                  BellSouth's poles, anchors or anchor/guy strands regarding
                  reimbursement for any expenses incurred by them in
                  transferring or rearranging their facilities to accommodate
                  the placement or attachment of MCIm's facilities in or to
                  BellSouth's structures.

                  1.7.6   MAKE-READY WORK ON AN EXPEDITED BASIS.

                        1.7.6.1.1   If MCIm is willing to authorize BellSouth
                        to perform make-ready work on an expedited basis, and
                        if BellSouth agrees to perform the work on such a
                        basis, BellSouth shall recalculate the estimated
                        make-ready charges. If MCIm accepts BellSouth's
                        offer, upon completion of the make-ready work MCIm
                        shall pay such additional charges, if any.

                  1.7.7   LICENSE. When MCIm's application for a pole
                  attachment or conduit occupancy license is approved, and all
                  required make-ready work completed, BellSouth will execute and
                  return a signed authorization to MCIm, as appropriate,
                  authorizing MCIm to attach or place the specified facilities
                  on BellSouth's poles or in BellSouth's conduit or ducts.

                          1.7.7.1   Each license issued under this Attachment
                          shall authorize MCIm to attach to BellSouth's poles
                          or place or maintain in BellSouth's conduit or ducts
                          only those facilities specifically described in the
                          license, and no others.

                          1.7.7.2   Except as expressly stated to the contrary
                          in individual licenses issued hereunder, each license
                          issued pursuant to this Attachment shall incorporate
                          all terms and conditions of this Attachment whether
                          or not such terms or conditions are expressly
                          incorporated by reference on the face of the license
                          itself.

         1.8      CONSTRUCTION OF MCIm's FACILITIES

                                                              Attachment VI - 28
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  1.8.1   CONSTRUCTION SCHEDULE. MCIm shall submit with MCIm's
                  license application a proposed or estimated construction
                  schedule. Promptly after the issuance of a license permitting
                  MCIm to attach facilities to BellSouth's poles or place
                  facilities in BellSouth's conduit or ducts, MCIm shall provide
                  BellSouth with an updated construction schedule and shall
                  thereafter keep BellSouth informed of significant anticipated
                  changes in the construction schedule. Construction schedules
                  required by this Attachment shall include, at a minimum, the
                  following information:

                          1.8.1.1   The name, title, business address, and
                          business telephone number of the manager responsible
                          for construction of the facilities;

                          1.8.1.2   The names of each contractor and
                          subcontractor which will be involved in the
                          construction activities;

                          1.8.1.3   The estimated dates when construction will
                          begin and end; and

                          1.8.1.4   The approximate dates when MCIm or persons
                          acting on MCIm's behalf will be performing
                          construction work in connection with the placement of
                          MCIm's facilities in BellSouth's conduit or ducts.

                  1.8.2   ADDITIONAL PRE-CONSTRUCTION PROCEDURES FOR FACILITIES
                  PLACED IN CONDUIT SYSTEM. The following procedures shall apply
                  before MCIm places facilities in BellSouth's conduit system:

                          1.8.2.1   MCIm shall give written notice of the type
                          of facilities which are to be placed; and

                          1.8.2.2   BellSouth shall designate the manner in
                          which MCIm's facilities will enter and exit
                          BellSouth's conduit system, and the specific location
                          and manner of installation of any associated
                          equipment which is permitted by BellSouth to occupy
                          the conduit system. BellSouth shall provide to MCIm
                          space in manholes for racking and storage of up to
                          fifty (50) feet of cable, provided space is
                          available.

                  1.8.3   BELLSOUTH NOT RESPONSIBLE FOR CONSTRUCTING OR PLACING
                  FACILITIES. BellSouth shall have no obligation to construct
                  any facilities for MCIm or to attach MCIm's facilities to, or
                  place MCIm's facilities in, BellSouth's poles or conduit
                  system, except as

                                                              Attachment VI - 29
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  may be necessary to facilitate the interconnection of
                  unbundled network elements or except to the extent expressly
                  provided in this Attachment, any license issued hereunder, or
                  by the Telecommunications Act of 1996 or any other applicable
                  law.

                  1.8.4   MCIM RESPONSIBLE FOR CONSTRUCTING, ATTACHING AND
                  PLACING FACILITIES. Except where otherwise mutually agreed by
                  MCIm and BellSouth, MCIm shall be responsible for constructing
                  its own facilities and attaching those facilities to, or
                  placing them in BellSouth's poles, conduit or ducts at MCIm's
                  sole cost and expense. MCIm shall be solely responsible for
                  paying all persons and entities who provide materials, labor,
                  access to real or personal property, or other goods or
                  services in connection with the construction and placement of
                  MCIm's facilities and for directing the activities of all
                  persons acting on MCIm's behalf while they are physically
                  present on BellSouth's pole, in any part of BellSouth's
                  conduit system or in the vicinity of BellSouth's poles or
                  conduit system.

                  1.8.5   COMPLIANCE WITH APPLICABLE STANDARDS, HEALTH AND
                  SAFETY REQUIREMENTS, AND OTHER LEGAL REQUIREMENTS. MCIm shall
                  construct its facilities in accordance with the provisions of
                  this Attachment and all licenses issued hereunder.

                          1.8.5.1   MCIm shall construct, attach and place its
                          facilities in compliance with all Requirements and
                          Specifications set forth above in Section 1.3 of this
                          Attachment.

                          1.8.5.2   MCIm shall satisfy all Legal Requirements
                          set forth above in Section 1.4 of this Attachment.

                          1.8.5.3   MCIm shall not permit any person acting on
                          MCIm's behalf to perform any work on BellSouth's
                          poles or within BellSouth's conduit system without
                          first verifying, to the extent practicable, on each
                          date when such work is to be performed, that the
                          condition of the pole or conduit system is suitable
                          for the work to be performed. If MCIm or any person
                          working on MCIm's behalf determines that the
                          condition of the pole or conduit system is not
                          suitable for the work to be performed, MCIm shall
                          notify BellSouth of the condition of the pole or
                          conduit system in question and shall not proceed with
                          construction activities until MCIm is satisfied that
                          the work can be safely performed.

                  1.8.6   CONSTRUCTION NOTICES. If requested to do so, MCIm
                  shall provide BellSouth with information to reasonably assure

                                                              Attachment VI - 30
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  BellSouth that construction has been performed in accordance
                  with all applicable standards and requirements.

                  1.8.7   MANHOLE AND CONDUIT BREAK-OUTS. MCIm shall be
                  permitted to add conduit ports to BellSouth manholes when
                  existing conduits do not provide the pathway connectivity
                  needed by MCIm; provided the structural integrity of the
                  manhole is maintained, and sound engineering judgment is
                  employed.

         1.9      USE AND ROUTINE MAINTENANCE OF MCIm's FACILITIES

                  1.9.1   USE OF MCIM'S FACILITIES. Each license granted under
                  this Attachment authorizes MCIm to have access to MCIm's
                  facilities on or in BellSouth's poles, conduits and ducts as
                  needed for the purpose of serving MCIm's customers, including,
                  but not limited to, powering electronics, monitoring
                  facilities, or transporting signaling.

                  1.9.2   ROUTINE MAINTENANCE OF MCIM'S FACILITIES. Each license
                  granted under this Attachment authorizes MCIm to engage in
                  routine maintenance of MCIm's facilities located on or in
                  BellSouth's poles, conduits, ducts and ROW pursuant to such
                  license. MCIm shall give reasonable notice to the affected
                  public authority or private landowner as appropriate before
                  commencing the construction or installation of its attachments
                  or making any material alterations thereto. MCIm shall give
                  reasonable notice to BellSouth before performing any work,
                  whether or not of a routine nature, in BellSouth's conduit
                  system.

                  1.9.3   MCIM RESPONSIBLE FOR MAINTENANCE OF MCIM'S FACILITIES.
                  MCIm shall maintain its facilities in accordance with the
                  provisions of this Attachment (including but not limited to
                  all Requirements set forth above in Section 1.3 of this
                  Attachment) and all licenses issued hereunder. MCIm shall be
                  solely responsible for paying all persons and entities who
                  provide materials, labor, access to real or personal property,
                  or other goods or services in connection with the maintenance
                  of MCIm's facilities and for directing the activities of all
                  persons acting on MCIm's behalf while they are physically
                  present on BellSouth's poles, within BellSouth's conduit
                  system or in the immediate vicinity of such poles or conduit
                  system.

                  1.9.4   BELLSOUTH NOT RESPONSIBLE FOR MAINTAINING MCIM'S
                  FACILITIES. BellSouth shall have no obligation to maintain any
                  facilities which MCIm has attached or connected to, or placed
                  in, BellSouth's poles, conduits, ducts or any portion of
                  BellSouth's conduit system, except to the extent expressly
                  provided by the

                                                              Attachment VI - 31
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  provisions of this Attachment or any license issued hereunder,
                  or by the Telecommunications Act of 1996 or other applicable
                  laws, rules or regulations.

                  1.9.5   INFORMATION CONCERNING THE MAINTENANCE OF MCIM'S
                  FACILITIES. Promptly after the issuance of a license
                  permitting MCIm to attach facilities to, or place facilities
                  in BellSouth's poles, conduits or ducts, MCIm shall provide
                  BellSouth with the name, title, business address, and business
                  telephone number of the manager responsible for routine
                  maintenance of MCIm's facilities, and shall thereafter notify
                  BellSouth of changes to such information. The manager
                  responsible for routine maintenance of MCIm's facilities
                  shall, on BellSouth's request, identify any contractor,
                  subcontractor, or other person performing maintenance
                  activities on MCIm's behalf at a specified site and shall, on
                  BellSouth's request, provide such additional documentation
                  relating to the maintenance of MCIm's facilities as reasonably
                  necessary to demonstrate that MCIm and all persons acting on
                  MCIm's behalf are complying with the requirements of this
                  Attachment and licenses issued hereunder.

                  1.9.6   IDENTIFICATION OF PERSONNEL AUTHORIZED TO HAVE ACCESS
                  TO MCIM'S FACILITIES. All personnel authorized to have access
                  to MCIm's facilities shall, while working on BellSouth's
                  poles, in its conduit system or ducts or in the vicinity of
                  such poles, ducts or conduit systems, carry with them suitable
                  identification and shall, upon the request of any BellSouth
                  employee, produce such identification.

         1.10     MODIFICATION AND REPLACEMENT OF MCIm's FACILITIES

                  1.10.1  NOTIFICATION OF PLANNED MODIFICATION OR REPLACEMENT OF
                  FACILITIES. MCIm shall, when practicable, notify BellSouth in
                  writing at least 60 days before adding to, relocating,
                  replacing or otherwise modifying its facilities attached to a
                  BellSouth pole, anchor or anchor/guy strand or located in any
                  BellSouth conduit or duct. The notice shall contain sufficient
                  information to enable BellSouth to determine whether the
                  proposed addition, relocation, replacement, or modification is
                  permitted under MCIm's present license or requires a new or
                  amended license.

                  1.10.2  NEW OR AMENDED LICENSE REQUIRED. A new or amended
                  license will be required if the proposed addition, relocation,
                  replacement, or modification:

                          1.10.2.1  Requires that MCIm use additional space on
                          BellSouth's poles or in its conduits or ducts
                          (including but

                                                              Attachment VI - 32
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          not limited to any additional ducts, inner ducts, or
                          substantial space in any handhole or manhole) on
                          either a temporary or permanent basis; or

                          1.10.2.2  Results in the size or location of MCIm's
                          facilities on BellSouth's poles or in its conduit or
                          ducts being appreciably different from those
                          described and authorized in MCIm's present license
                          (e.g. different duct or size increase causing a need
                          to re-calculate storm loadings, guying, or pole
                          class).

         1.11     REARRANGEMENT OF FACILITIES AT THE REQUEST OF ANOTHER

                  1.11.1  MAKE-READY WORK AT THE REQUEST OF MCIM. If, prior to
                  the issuance of a license, MCIm determines that any pole,
                  anchor, anchor/guy strand, conduit or duct is inadequate to
                  accommodate MCIm's proposed pole attachment or conduit
                  occupancy or that it will be necessary or desirable for
                  BellSouth or any other person or entity to rearrange existing
                  facilities or structures to accommodate MCIm, MCIm shall
                  promptly advise BellSouth of the make-ready work it believes
                  necessary to enable the accommodation of MCIm's facilities.

                          1.11.1.1  BellSouth shall determine, in the exercise
                          of sound engineering judgment, whether or what such
                          make-ready work is necessary or possible. In
                          determining whether make-ready work is necessary
                          BellSouth shall endeavor to minimize its costs. If it
                          is determined that such make-ready work is required,
                          within twenty (20) business days of such
                          determination BellSouth shall provide MCIm with the
                          estimated costs for make-ready work and a Make-Ready
                          Due Date.

                          1.11.1.2  MCIm shall be solely responsible for
                          negotiating with persons or entities other than
                          BellSouth for the rearrangement of such persons' or
                          entities' facilities or structures and, except where
                          such rearrangement is for the benefit of BellSouth
                          and/or other licensees as well as MCIm, shall be
                          solely responsible for paying all charges
                          attributable to the rearrangement of such facilities;
                          provided, however, that if facilities rearrangements
                          require new licenses from BellSouth, BellSouth shall
                          issue such licenses in conjunction with the issuance
                          of the applied-for license to MCIm.

                                                              Attachment VI - 33
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  1.11.2  REARRANGEMENT OF MCIM'S FACILITIES AT BELLSOUTH'S
                  REQUEST. MCIm acknowledges that, from time to time, it may be
                  necessary or desirable for BellSouth to change out poles,
                  relocate, reconstruct, or modify portions of its conduit
                  system or rearrange facilities contained therein or connected
                  thereto and that such changes may be necessitated by
                  BellSouth's business needs or authorized application of
                  another entity seeking access to BellSouth's poles or conduit
                  systems. MCIm agrees that MCIm will, upon BellSouth's request,
                  and at BellSouth's expense, but at no cost to MCIm,
                  participate with BellSouth (and other licensees) in the
                  relocation, reconstruction, or modification of BellSouth's
                  conduit system or facilities rearrangement. MCIm acknowledges
                  that, from time to time, it may be necessary or desirable for
                  BellSouth to change out poles, relocate, reconstruct, or
                  modify portions of its conduit system or rearrange facilities
                  contained therein or connected thereto as a result of an order
                  by a municipality or other governmental authority. MCIm shall,
                  upon BellSouth's request, participate with BellSouth (and
                  other licensees) in the relocation, reconstruction, or
                  modification of BellSouth's conduit system or facilities
                  rearrangement and pay its proportionate share of any costs of
                  such relocation, reconstruction, or modification that are not
                  reimbursed by such municipality or governmental authority.

                          1.11.2.1  MCIm shall make all rearrangements of its
                          facilities within such period of time as is jointly
                          deemed reasonable by the parties based on the amount
                          of rearrangements necessary and a desire to minimize
                          chances for service interruption or facility-based
                          service denial to an MCIm customer.

                          1.11.2.2  If MCIm fails to make the required
                          rearrangements within the time prescribed in 1.11.2.1
                          preceding or within such extended periods of time as
                          may be granted by BellSouth in writing, BellSouth may
                          perform such rearrangements with written notice to
                          MCIm, and MCIm shall reimburse BellSouth for actual
                          costs and expenses incurred by BellSouth in
                          connection with the rearrangement of MCIm's
                          facilities; provided, however, that nothing contained
                          in this Attachment or any license issued hereunder
                          shall be construed as requiring MCIm to bear any
                          expenses which, under the Telecommunications Act of
                          1996 or other applicable federal or state laws or
                          regulations, are to be allocated to persons or
                          entities other than MCIm; and

                                                              Attachment VI - 34
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          provided further, however, that MCIm shall have no
                          responsibility for rearrangement costs and expenses
                          relating to rearrangements performed for the purpose
                          of meeting BellSouth's business needs or the business
                          needs of any other licensee/joint user.

         1.12     EMERGENCY REPAIRS AND POLE REPLACEMENTS

                  1.12.1  Within sixty (60) days after the Effective Date of
                  this Agreement, BellSouth and MCIm shall mutually agree on a
                  non-discriminatory priority method to access BellSouth poles,
                  conduit and ROW in emergency situations.

                  1.12.2  MCIM RESPONSIBLE FOR EMERGENCY REPAIRS TO ITS OWN
                  FACILITIES. In general, MCIm shall be responsible for making
                  emergency repairs to its own facilities and for formulating
                  appropriate plans and practices which will enable it to make
                  such emergency repairs. BellSouth shall be under no obligation
                  to perform any repair or service restoration work of any kind
                  with respect to MCIm's facilities.

         1.13     INSPECTION BY BellSouth OF MCIm's FACILITIES

                  1.13.1  BELLSOUTH'S RIGHT TO MAKE PERIODIC OR SPOT
                  INSPECTIONS. BellSouth shall have the right to make periodic
                  or spot inspections at any time of any part of MCIm's
                  facilities attached to BellSouth's poles, anchors or
                  anchor/guy strands or occupying any BellSouth conduit or duct
                  for the limited purpose of determining whether MCIm's
                  facilities are in compliance with the terms of this Attachment
                  and licenses hereunder; provided that such inspections must be
                  non-invasive (e.g., no splice cases may be opened).

                          1.13.1.1  BellSouth will give MCIm advance written
                          notice of such inspections, and MCIm shall have the
                          right to have a representative attend such
                          inspections, except in those instances where safety
                          considerations justify the need for such inspection
                          without the delay of waiting until written notice has
                          been forwarded to MCIm.

                          1.13.1.2  Such inspections shall be conducted at
                          BellSouth's expense, provided, however, that MCIm
                          shall bear the cost of inspections as delineated in
                          Section 1.3.12.

                  1.13.2  NO DUTY TO MCIM. Neither the act of inspection by

                                                              Attachment VI - 35
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  BellSouth of MCIm's facilities nor any failure to inspect such
                  facilities shall operate to impose on BellSouth any liability
                  of any kind whatsoever or to relieve MCIm of any
                  responsibility, obligations or liability under this Attachment
                  or otherwise existing.

         1.14     NOTICE OF NONCOMPLIANCE

                  1.14.1  NOTICE OF NONCOMPLIANCE. If, at any time, BellSouth
                  determines that MCIm's facilities or any part thereof have not
                  been placed or maintained or are not being used in accordance
                  with the requirements of this Attachment , BellSouth may send
                  written notice to MCIm specifying the alleged noncompliance.
                  MCIm agrees to acknowledge receipt of the notice as soon as
                  practicable. If MCIm does not dispute BellSouth's assertion
                  that such facilities are not in compliance, MCIm agrees to
                  provide BellSouth with a schedule for bringing such facilities
                  into compliance, to bring the facilities into compliance
                  within a reasonable time, and to notify BellSouth in writing
                  when the facilities have been brought into compliance.

                  1.14.2  DISPUTES OVER ALLEGED NONCOMPLIANCE. If MCIm disputes
                  BellSouth's assertion that MCIm's facilities are not in
                  compliance, MCIm shall notify BellSouth in writing of the
                  basis for MCIm's assertion that its facilities are in
                  compliance.

                  1.14.3  FAILURE TO BRING FACILITIES INTO COMPLIANCE. If MCIm
                  has not brought the facilities into compliance within a
                  reasonable time or provided BellSouth with proof sufficient to
                  persuade BellSouth that BellSouth erred in asserting that the
                  facilities were not in compliance, and if BellSouth determines
                  in good faith that the alleged noncompliance causes or is
                  likely to cause material damage to BellSouth's facilities or
                  those of others users, BellSouth may, at its option and MCIm'
                  s expense, take such non-service affecting steps as may be
                  required to bring MCIm's facilities into compliance, including
                  but not limited to correcting any conditions which do not meet
                  the specifications of Section 1.3 of this Attachment .

                  1.14.4  CORRECTION OF CONDITIONS BY BELLSOUTH. If BellSouth
                  elects to bring MCIm's facilities into compliance as provided
                  by Section 1.14.3 of this Attachment, the provisions of this
                  Attachment shall apply.

                          1.14.4.1  BellSouth will, whenever practicable, notify
                          MCIm in writing before performing such work. The
                          written

                                                              Attachment VI - 36
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                          notice shall describe the nature of the work to be
                          performed and BellSouth's schedule for performing the
                          work.

                          1.14.4.2  If MCIm's facilities have become detached or
                          partially detached from supporting racks or wall
                          supports located within a BellSouth manhole,
                          BellSouth may, at MCIm's expense, reattach them but
                          shall not be obligated to do so. If BellSouth does
                          not reattach MCIm's facilities, BellSouth shall
                          endeavor to arrange with MCIm for the reattachment of
                          any facilities affected.

                          BellSouth shall, as soon as practicable after
                          performing the work, advise MCIm in writing of the
                          work performed or action taken. Upon receiving such
                          notice, MCIm shall inspect the facilities and take
                          such steps as MCIm may deem necessary to insure that
                          the facilities meet MCIm's performance requirements.

                  1.14.5  MCIM TO BEAR EXPENSES. MCIm shall bear all expenses
                  arising out of or in connection with any work performed to
                  bring MCIm's facilities into compliance with this Attachment;
                  provided, however that nothing contained in this Attachment or
                  any license issued hereunder shall be construed as requiring
                  MCIm to bear any expenses which, under applicable federal or
                  state laws or regulations, must be borne by persons or
                  entities other than MCIm.

         1.15     UNAUTHORIZED OCCUPANCY OR UTILIZATION OF BellSouth's
         FACILITIES

                  1.15.1  LICENSING OR REMOVAL OF UNAUTHORIZED ATTACHMENTS. If
                  any of MCIm's attachments shall be found attached to pole(s)
                  or occupying conduit systems for which no license is
                  outstanding, BellSouth, without prejudice to its other rights
                  or remedies under this Agreement, including termination of
                  licenses, may impose a charge and require MCIm to submit in
                  writing, within thirty (30) days after receipt of written
                  notification from BellSouth of the unauthorized attachment or
                  conduit occupancy, a pole attachment or conduit occupancy
                  license application. If such application is not received by
                  BellSouth within the specified time period, MCIm may be
                  required at BellSouth's option to remove its unauthorized
                  attachment or occupancy within sixty (60) days of the final
                  date for submitting the required application, or BellSouth may
                  at the end of such sixty (60) day period, at BellSouth's
                  option remove MCIm's facilities without liability, and the
                  expense of such removal shall be borne by MCIm. Charges for
                  any such unauthorized occupancy

                                                              Attachment VI - 37
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  shall be equal to the applicable license fees and charges
                  which would have been payable from and after the date such
                  facilities were first placed on BellSouth's poles or in
                  BellSouth's conduit system, if MCIm provides reasonable
                  documentation of such placement. If MCIm is unable to provide
                  such reasonable documentation the matter may be submitted to
                  the Dispute Resolution Procedures, described in Part A of this
                  Agreement. If BellSouth prevails in such Dispute Resolution,
                  then MCIm will pay two years worth of the applicable charges.

                  1.15.2  Nothing contained in the Agreement or any license
                  issued hereunder shall be construed as requiring MCIm to bear
                  any expenses which, under applicable federal or state laws or
                  regulations, must be borne by persons or entities other than
                  MCIm.

                  1.15.3  PROMPT PAYMENT OF APPLICABLE FEES AND CHARGES. Fees
                  and charges for unauthorized pole attachments and conduit
                  system occupancies, as specified herein and as modified from
                  time to time, shall be due and payable immediately whether or
                  not MCIm is permitted to continue the pole attachment or
                  conduit occupancy.

                  1.15.4  NO IMPLIED WAIVER OR RATIFICATION OF UNAUTHORIZED USE.
                  No act or failure to act by BellSouth with regard to said
                  unlicensed use shall be deemed as a ratification of the
                  unlicensed use; and if any license should be subsequently
                  issued, said license shall not operate retroactively or
                  constitute a waiver by BellSouth of any of its rights or
                  privileges under this Attachment or otherwise; provided,
                  however, that MCIm shall be subject to all liabilities,
                  obligations and responsibilities of this Agreement in regard
                  to said unauthorized use from its inception.

         1.16     REMOVAL OF MCIm's FACILITIES

                  1.16.1  POLE ATTACHMENTS. MCIm, at its expense, will remove
                  its attachments from any of BellSouth's poles within thirty
                  (30) days after termination of the license covering such
                  attachments. If MCIm fails to remove its attachments within
                  such thirty (30) day period, BellSouth shall have the right to
                  remove such attachments at MCIm's expense and without any
                  liability on the part of BellSouth for damage or injury to
                  MCIm' s attachments unless caused by the negligence or
                  intentional misconduct of BellSouth.

                  1.16.2  CONDUIT OCCUPANCY. MCIm, at its expense, will remove
                  its communications facilities from a conduit system within

                                                              Attachment VI - 38
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  sixty (60) days after:

                          1.16.2.1  Termination of the license covering such
                          conduit occupancy; or

                          1.16.2.2  The date MCIm replaces its existing
                          facilities in one duct with substitute facilities in
                          another duct.

                  1.16.3  If MCIm fails to remove its facilities within the
                  specified period, BellSouth shall have the right to remove
                  such facilities at MCIm's expense and without any liability
                  on the part of BellSouth for damage or injury to such
                  facilities unless caused by the negligence or intentional
                  misconduct of BellSouth.

                  1.16.4  CONTINUING RESPONSIBILITY FOR FEES AND CHARGES. MCIm
                  shall remain liable for and pay to BellSouth all fees and
                  charges pursuant to provisions of this Agreement until all of
                  MCIm's facilities are physically removed from BellSouth's
                  poles or conduit system.

         1.17     FEES, CHARGES, AND BILLING

                  1.17.1  LICENSE CHARGES. License charges commence on the first
                  day of the calendar month following the date a license is
                  issued. Such charges cease as of the final day of the calendar
                  month preceding the month in which the attachment or occupancy
                  is physically removed or the utilization is discontinued. A
                  one-month minimum charge is applicable to all licenses.

                  1.17.2  NOTICE OF RATE AND COMPUTATION OF CHARGES. On or about
                  November 1 of each year, BellSouth will notify MCIm by
                  certified mail, return receipt requested, of the rental rate
                  and pole transfer rate to be applied in the subsequent
                  calendar year. The letter of notification shall be
                  incorporated in, and governed by, the terms and conditions of
                  this Agreement. Attachment and occupancy rates shall be
                  applied to the number of pole(s) and duct feet of conduit for
                  which licenses have been issued before December 1 of each
                  calendar year. Charges for attachment(s) and occupancy which
                  commenced during the preceding twelve (12) month period will
                  be prorated accordingly.

         1.18     ADVANCE PAYMENT AND IMPUTATION

                  1.18.1  ATTACHMENT AND OCCUPANCY FEES. Fees for pole

                                                              Attachment VI - 39
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                  attachment and conduit occupancy shall be based on the
                  facilities for which licenses have been issued as of the date
                  of billing by BellSouth, shall be computed as set forth in
                  Attachment 1 of this Agreement and shall be payable annually.

                          1.18.1.1  Charges associated with newly licensed
                          attachments or occupancies and other attachments or
                          occupancies of less than the entire annual billing
                          period shall be prorated.

                          1.18.1.2  Charges shall be prorated retroactively in
                          the event of the removal of MCIm's facilities.

                  1.18.2  The amount of any advance payment required under this
                  Section 3.20 shall be due within sixty (60) days after receipt
                  of an invoice from BellSouth.

                  1.18.3  IMPUTATION. BellSouth shall impute to its costs of
                  providing telecommunications services (and charge any
                  affiliate, subsidiary, or associate company engaged in the
                  provision of such services) an equal amount to the charges set
                  forth in this Attachment for all of the conduits, ducts, and
                  poles it occupies and uses.

         1.19     ASSURANCE OF PAYMENT

                  1.19.1  In the event MCIm fails to demonstrate credit
                  worthiness, MCIm may be required to furnish a bond, letter of
                  credit or other evidence of financial security having a
                  minimum face amount of $10,000.00 per state or $50,000.00 per
                  region. Such bond, letter of credit or other security shall be
                  in a form satisfactory to BellSouth and may be increased from
                  time to time as reasonably required by BellSouth to guarantee
                  the performance of all obligations of MCIm hereunder. The
                  amount of the bond, letter of credit or other security shall
                  not operate as a limitation upon the obligations of MCIm
                  hereunder.

Section 2.  Unused Transmission Media

         2.1      Definition:

         Dark Fiber is unused strands of optical fiber. Dark Fiber also includes
         strands of optical fiber existing in aerial or underground structure
         which have lightwave repeater (regenerator or optical amplifier)
         equipment interspliced to at appropriate distances, but which has no
         line terminating

                                                              Attachment VI - 40
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

         elements terminated to such strands to operationalize its transmission
         capabilities.

         2.2      BellSouth shall not be required to provide dark fiber as an
         unbundled network element. However, MCIm shall have access to lit
         BellSouth fiber and BellSouth will not refuse such access merely
         because such fiber is now dark.

                                                              Attachment VI - 41
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                                    Exhibit I

                        ADMINISTRATIVE FORMS AND NOTICES

This Exhibit II lists the types of administrative forms to be utilized in
connection with this Attachment .

                          LIST OF ADMINISTRATIVE FORMS

Authorization for Make-Ready Work
Application and Conduit Occupancy License
Conduit System Diagram
Cable to Occupy Conduit
Equipment Housings to be Placed in manholes
Notification of Surrender or Modification of Conduit
  Occupancy License by Licenses
Notifications of Unauthorized Attachments by Applicant
Application and Pole Attachment License
Pole, Anchor and Guy Strand Details
Application and Unused Transmission Media License
Application Survey Data
Notification of Surrender or Modification of Pole
  Attachment License by Licenses

                                                              Attachment VI - 42
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                               TABLE OF CONTENTS

                                 ATTACHMENT VII
                               NUMBER PORTABILITY

            Section 1. BellSouth Provision of Number Portability        VII-1

            Section 2. Interim Number Portability (INP)                 VII-1

            Section 3. Number Portability (NP)                          VII-4

            Section 4. Requirement for INP and NP                       VII-8


                                                              ATTACHMENT VII - i
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                                 ATTACHMENT VII

                               NUMBER PORTABILITY

SECTION 1. BELLSOUTH PROVISION OF NUMBER PORTABILITY

BellSouth and MCIm shall provide number portability in accordance
with the requirements of the Act and applicable FCC rules and Regulations in
effect. Interim Number Portability (INP) will be provided by BellSouth to MCIm,
and MCIm to BellSouth, immediately upon the Effective Date of this Agreement.
INP will be provided with minimum impairment of functionality, quality,
reliability and convenience to subscribers of both companies' services. The
parties will provide Permanent Number Portability (PNP) as soon as it is
technically feasible, in conformance with FCC Orders, Rules and Regulations in
effect and the Act.

SECTION 2. INTERIM NUMBER PORTABILITY (INP)

INP shall be provided by Remote Call Forwarding ("RCF"), Route Indexing, Route
Indexing - Portability Hub, Local Exchange Routing Guide (LERG) reassignment,
and FLEX-DID, and MCI shall select which of these methods shall be used for each
application. MCIm shall specify on a per telephone number basis which method of
INP is to be employed and BellSouth shall provide such method to the extent
Technically Feasible.

         2.1 Remote Call Forwarding: Remote Call Forwarding (RCF) is an INP
         method to provide subscribers with service-provider portability by
         redirecting calls within the telephone network. When RCF is used to
         provide interim number portability, calls to the ported number will
         first route to the BellSouth switch to which the ported number was
         previously assigned. The BellSouth switch will then forward the call to
         a number associated with the MCIm designated switch to which the number
         is ported. MCIm may order any additional paths to handle multiple
         simultaneous calls to the same ported telephone number as specified by
         MCIm.

         2.2 FLEX-DID is an INP method that makes use of direct inward dialing
         trunks. Each FLEX-DID trunk group used for INP is dedicated to carrying
         FLEX-DID INP traffic between the BellSouth end office and the MCIm
         switch. Traffic on these trunks cannot overflow to other trunks, so the
         number of trunks shall be conservatively engineered by BellSouth.
         BellSouth shall provide FLEX-DID on an individual number basis as
         specified by MCIm. Also, inter-switch signaling is usually limited to
         multi-frequency (MF). This precludes passing CLID to the MCIm switch.
         However, BellSouth intends to

                                                              ATTACHMENT VII - 1
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

         use SS7.

         2.3 Route Indexing: Route Indexing may take two forms: Route
         Index-Portability Hub (RI-PH) or Directory Number-Route Index (DN-RI).

            2.3.1 Where Technically Feasible, RI-PH will route a dialed call to
            the BellSouth switch associated with the NXX of the dialed number.
            The BellSouth switch shall then insert a prefix onto the dialed
            number which identifies how the call is to be routed to MCIm. The
            prefixed dialed number is transmitted to the BellSouth tandem switch
            to which MCIm is connected.

            The prefix is removed by the operation of the tandem switch and the
            dialed number is routed to MCIm's switch so the routing of the call
            can be completed by MCIm.

            2.3.2 DN-RI is a form of RI-PH that requires direct trunking between
            the BellSouth switch to which the ported number was originally
            assigned and the MCIm switch to which the number has been ported.
            The BellSouth switch shall send the originally dialed number to the
            MCIm switch without a prefix.

            2.3.3 BellSouth shall provide RI-PH or DN-RI on an individual
            telephone number basis, as designated by MCIm. Where Technically
            Feasible, MCIm may designate both methods so that calls to ported
            numbers are first directed to the MCIm switch over direct trunks but
            may overflow to tandem trunks if all trunks in the direct group are
            occupied.

            2.3.4 For both RI-PH and DN-RI the trunks used may, at MCIm's
            option, and where Technically Feasible, be the same as those used
            for exchange of other local traffic and toll traffic with BellSouth.
            At MCIm' s option, the trunks shall employ SS7 or in band signaling.

         2.4 LERG Reassignment: Portability for an entire NXX shall be provided
         by utilizing reassignment of the block to MCIm through industry
         recognized guidelines and the Local Exchange Routing Guide (LERG).
         Updates to translations in the BellSouth switching office from which
         the telephone number is ported will be made by the BellSouth prior to
         the date on which LERG changes become effective, in order to redirect
         calls to the MCIm switch via route indexing or the INP method specified
         by MCIm.

         2.5 Other Currently Available Number Portability Provisions:

            2.5.1 BellSouth shall exchange with MCIm, SS7 TCAP messages as

                                                              ATTACHMENT VII - 2
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

            required for the implementation of Custom Local Area Signaling
            Services (CLASS) or other features available in the BellSouth
            network. CLID shall be passed by BellSouth to MCIm.

            2.5.2 Upon notification from MCIm that it will be initiating INP,
            BellSouth shall disclose to MCIm any technical or capacity
            limitations that would prevent the use of the requested INP method
            in a particular switching office. BellSouth and MCIm shall cooperate
            in the process of porting numbers to minimize subscriber
            out-of-service time, including updating switch translations where
            necessary within timeframes on parity with establishment of new
            services for BellSouth's customers, but in any event BellSouth
            shall use its best efforts not to exceed thirty (30) minutes after
            notification that physical cut-over has been completed (or
            initiated), as MCIm may designate.

            2.5.3 For INP, MCIm shall have the right to use the existing
            BellSouth 911 infrastructure for all 911 capabilities. When an INP
            method is used for MCIm subscribers, both the ported numbers and
            shadow numbers shall be stored in 911/ALI databases. MCIm shall have
            the right to verify the accuracy of the information in the PSAP
            databases.

            2.5.4 When any INP method is used to port a subscriber, the donor
            provider must maintain the Line Information Database (LIDB) record
            for that number to reflect appropriate conditions as reported to it
            by the porting service provider. The donor must outclear call
            records to MCIm for billing and collection from the subscriber. MCIm
            shall receive revenue for LIDB look-ups.

            2.5.5 BellSouth should send a CARE transaction 2231 to notify IXC
            that access is now provided by a new CLEC for that number.

                                                              ATTACHMENT VII - 3
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

SECTION 3. NUMBER PORTABILITY (NP)

BellSouth and MCIm agree to implement NP as follows, to the extent the parties
mutually agree the following is consistent with FCC orders in effect in FCC
Docket 95-116 and the directions from the appropriate industry forum:

            3.1.1 The requirements for NP shall include the following:

            3.1.2 Subscribers must be able to change local service providers and
            retain the same telephone number(s) consistent with FCC Rules and
            Regulations.

            3.1.3 The NP network architecture shall not subject alternate local
            exchange carriers to any degradation of service compared to
            BellSouth in any relevant measure, including transmission quality,
            switching and transport costs, increased call set-up time and
            post-dial delay, and MCIm shall not be required to rely on the
            BellSouth network for calls completing to its ported subscribers.

            3.1.4 When an office is equipped with NP, all NXXs in the office
            shall be defined as portable and translations will be changed in all
            service provider switches to open those NXXs for database queries.
            If a switch serves multiple rate centers, then at a minimum, all of
            the NXXs for a rate center in that switch shall be made portable
            when any one of them is turned up.

            3.1.5 When an NXX is defined as portable, it shall also be defined
            as portable in all LRN-capable offices which have direct trunks to
            the given switch.

            3.1.6 Upon introduction of LRN in a market area, the tandems (local
            and access) shall be among the first converted, with no unreasonable
            delay. All portable NXXs shall be recognized in these tandems as
            portable, with queries launched from these switches.

            3.1.7 Left blank intentionally

            3.1.8 When a subscriber ports to another service provider and has
            previously secured a reservation of line numbers from the donor
            provider for possible activation at "some future point, these
            reserved but inactive numbers shall "port" along with the active
            numbers being ported by the subscriber in order to ensure that the
            end user subscriber will be permitted to expand its service using
            the same number range it could use if it remained with the donor
            provider.

                                                              ATTACHMENT VII - 4
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

            3.1.9 During the process of porting a subscriber, the donor service
            provider shall implement the 10-Digit trigger feature. When the
            donor provider receives the porting request, the 10-Digit trigger
            shall be applied to the Subscriber's line at least 24 hours prior
            to the order due date in order to overcome donor network time delays
            in the disconnection of the subscriber. Alternatively, when an
            activation notice is sent to an NPAC to trigger a broadcast to
            service provider databases, the donor switch shall have its
            translations changed to disconnect the subscriber's line within
            fifteen (15) minutes of the donor network Local SMS's having
            received the broadcast.

         3.2 Joint Cooperation

            Both MCIm and BellSouth shall:

            Support all emergency and operator services.

         Use scarce numbering resources efficiently and administer such
         resources in a competitively neutral manner.

         Jointly cooperate with each other to ensure that both carriers shall be
         able to rate and bill all types of calls.

         Jointly cooperate with each other to apply NP consistently on a
         nationwide basis, and in accordance with all Federal Communication
         Commission directives.

         3.3 Location Routing Number (LRN)

            BellSouth and MCIm shall work to implement the LRN-NP solution.

            3.3.1 A ten-digit code, consistent with the North American Numbering
            Plan, called the location routing number (LRN) shall be used as a
            network address for each switch that terminates subscriber lines,
            i.e. an end office. LRN shall support existing six-digit routing and
            may be implemented without changes to existing switch routing
            algorithms. In existing end offices, the LRN shall be selected from
            one of its existing NPA-NXXs. New end offices shall be assigned LRNs
            through normal administrative processes.

            3.3.2 LRN employs an "N-1" Query Strategy for interLATA or intraLATA
            toll calls, by which the originating carrier will pass the call to
            the appropriate toll carrier who will perform a query to an external
            routing database and route the call to the appropriate terminating
            local carrier either directly or through an access tandem office.
            For a local

                                                              ATTACHMENT VII - 5
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

            call to a ported number, the originating carrier is the "N-1"
            carrier. It will perform an external database query and pass the
            call to the appropriate terminating carrier. The "N-1" methodology
            will be used to extend portability on a phased, region-by-region
            basis and it does not place BellSouth or other carriers needlessly
            in the call path.

            3.3.3 BellSouth shall furnish MCIm with the first six digits of the
            originating LRN when it supplies MCIm with the Jurisdiction
            Information Parameter for the Initial Address Message.

            3.3.4 BellSouth agrees to begin the introduction of LRN to end user
            subscribers who may begin changing local service providers and
            retaining their existing telephone number based on the time line set
            out by the FCC in its Telephone Number Portability Order (CC Docket
            No. 95-116), or as per a State order if such time for introduction
            of LRN set by the State is earlier than would result under the FCC
            Order.

            3.3.5 The generic requirements for LRN are specified in the
            following publications: Generic Switching and Signaling Requirements
            for Number Portability, Issue 1.03, September 4, 1996 [Editor -
            Lucent Technologies, Inc.]; Generic Requirements for SCP Application
            and GTT Function for Number Portability, Issue 0.31, Final Draft,
            March 24, 1996 [Editor - Ameritech Inc.]; and Generic Operator
            Services Switching Requirements for Number Portability, Issue 1.00,
            Final Draft, April 12, 1996 [Editor - Nortel].

         3.4 Additional NP Requirements

            3.4.1 For local calls to a portable NXX native to another
            end-office', BellSouth shall query an external database as soon as
            the call reaches the first NP-capable switch in the call path. An
            LRN-capable originating switch shall query on a local call to a
            portable NXX as soon as it determines that it (the originating
            switch) does not serve the dialed number.

            3.4.2 BellSouth shall be the default carrier for database queries
            where a participating carrier is unable to perform its own query due
            to abnormal conditions.

            3.4.3 BellSouth will provide MCIm INP and NP for subscribers moving
            to a different location, or staying at the same location, within the
            same rate center area.

         3.5 SMS Administration

                                                              ATTACHMENT VII - 6
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

         BellSouth will work cooperatively with other local service providers to
         establish the NP Service Management System (SMS). The SMS shall be
         administered by a neutral third party, to provide for the efficient
         porting of numbers between carriers. There must be one exclusive NPAC
         per portability State or region, and BellSouth shall provide all
         information uploads and downloads regarding ported numbers to/from,
         respectively, the exclusive NPAC. BellSouth and MCIm shall cooperate to
         facilitate the expeditious deployment of LRN-based NP through the
         process prescribed by the FCC, including, but not limited to,
         participation in the selection of a neutral third party and development
         of SMS, as well as SMS testing for effective procedures, electronic
         system interfaces, and overall readiness for use consistent with that
         specified for Provisioning in this Agreement.

         3.6 Cut-Over Process

         BellSouth shall cooperate in the process of porting numbers from one
         carrier to another so as to limit service outage for the ported
         subscriber. This shall include, but not be limited to, updating its
         network element translations within five (5) minutes following
         notification by the industry SMS, or ported-to local service provider,
         and deploying such temporary translations as may be required to
         minimize service outage, e.g., unconditional triggers. Also, MCIm shall
         have the right to determine who initiates the order for INP in specific
         cut-over situations.

         For a Coordinated Cutover Environment, BellSouth shall verbally
         coordinate with MCIm the disconnect and switch translation as close to
         the requested time as possible. The coordination shall be pre-specified
         by MCIm and agreed to by both parties and in no case shall begin more
         than 20 minutes after the agreed upon time.

         For a Non-Coordinated Cutover Environment, BellSouth shall schedule a
         mechanized update of disconnect and switch translations at the MCIm
         requested cutover time (frame due time). Such updates will be available
         seven (7) days a week, twenty-four (24) hours a day. BellSouth shall
         provide an Operation contact whom MCIm can reach in the event manual
         intervention is needed to complete the cutover. In the event of manual
         intervention, BellSouth shall notify MCIm immediately of the need for
         manual intervention and shall provide MCIm with a completion schedule
         and project plan for resolving the issue requiring intervention within
         thirty (30) minutes from the time the need for manual intervention was
         identified, and shall resolve such issue as soon as possible.

         3.7 With respect to operator services and directory listings associated
         with NP for MCIm subscribers, BellSouth shall provide the following
         when NP is in place:

                                                              ATTACHMENT VII - 7
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

            3.7.1 The Provisions in 4.6.1.1~.4.6.1.5 below, shall apply when NP
            is in place.

            3.7.2 If Integrated Services Digital Network User Part (ISUP)
            signaling is used BellSouth shall provide the Jurisdiction
            Information Parameter in the SS7 Initial Address Message. (See
            Generic Switching and Signaling Requirements for Number Portability,
            Issue 1.03, September 4, 1996 (Editor - Lucent Technologies, Inc.])

            3.7.3 BellSouth shall provide a 10-Digit Global Title Translation
            (GTT) Node for routing queries for TCAP-based operator services
            (e.g., LIDB).

         3.8 BellSouth OSS shall meet all requirements specified in "Generic
         Operator Services Switching Requirements for Number Portability," Issue
         1.00, Final Draft, April 12, 1996.

SECTION 4. REQUIREMENTS FOR INP AND NP

         4.1 White and Yellow Page Listings

         LEC shall provide and maintain for MCIm one (1) white page and one (1)
         yellow page (if applicable) listing for each MCIm subscriber that has
         ported its number from BellSouth, consistent with that specified for
         Provisioning in this Agreement. The listing and handling of listed and
         nonlisted telephone numbers will be at least at parity with that
         provided by BellSouth to its own subscribers.

         4.2 Call Referral Announcements

         BellSouth shall allow MCIm to order call referral announcements, and
         specify the particular announcement from BellSouth's standard set of
         call referral announcement options, on a per telephone number basis,
         for telephone numbers which MCIm has ported from BellSouth to MCIm and
         for which such ILNP measures have, at MCIm's direction, been
         terminated.

         4.3 Testing

         BellSouth and MCIm shall cooperate in conducting MCIm's testing to
         ensure interconnectivity between systems. BellSouth shall inform MCIm
         of any system updates that may affect the MCIm network and BellSouth
         shall, at MCIm's request, perform tests to validate the operation of
         the network. Additional testing requirements may apply as specified by
         this Agreement.

                                                              ATTACHMENT VII - 8
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

         4.4 Engineering and Maintenance

         BellSouth and MCIm will cooperate to ensure that performance of
         trunking and signaling capacity is engineered and managed at levels
         which are at least at parity with that provided by BellSouth to its
         subscribers and to ensure effective maintenance testing through
         activities such as routine testing practices, network trouble isolation
         processes and review of operational elements for translations, routing
         and network fault isolation.

         Additional specific engineering and maintenance requirements shall
         apply as specified in this Agreement.

         4.5 Recording and Billing

         BellSouth shall provide MCIm with accurate billing and Subscriber
         Account Record Exchange data for MCIm subscribers whose numbers have
         been ported.

            4.5.1 Calls originated from RCF ported numbers in BellSouth end
            offices and sent to the MCIm network must signal the shadow number
            in the Calling Party Number (CgPN) parameter and ported number in
            the Charge Number (CN) parameter in the SS7 Initial Address Message.

         4.6 Operator Services and Directory Listings.

         With respect to operator services and directory listings associated
         with NP for MCIm subscribers, BellSouth shall provide the following:

            4.6.1 While INP is deployed and prior to conversion to NP:

                4.6.1.1 BellSouth shall allow MCIm to order provisioning of
                Telephone Line Number (TLN) calling cards and Billed Number
                Screening (BNS), in its LIDB, for numbers ported to MCIm, as
                specified by MCIm. BellSouth shall continue to allow MCIm access
                to its LIDB. Other LIDB provisions are specified in this
                Agreement.

                4.6.1.2 Where BellSouth has control of directory listings for
                NXX codes containing ported numbers, BellSouth shall maintain
                entries for ported numbers as specified by MCIm.

                                                            ATTACHMENT VII - 9
<PAGE>

           MCIMETRO - BELLSOUTH MISSISSIPPI INTERCONNECTION AGREEMENT

                                 ATTACHMENT VIII

                                TABLE OF CONTENTS

                          BUSINESS PROCESS REQUIREMENTS

                    SECTION 1. GENERAL BUSINESS REQUIREMENTS

1.1 PROCEDURES
         1.1.1 BellSouth Contact with Subscribers
         1.1.2 Expedite, Escalation, and Disaster Procedures
         1.1.3 Operational and Technological Changes
         1.1.4 Subscriber of Record
         1.1.5 Work Center Interface Procedures

1.2  SERVICE OFFERINGS
         1.2.1 Changes in Retail Service Offerings
         1.2.2 Essential Services
         1.2.3 Caller ID
         1.2.4 TTY/TDD
         1.2.5 Blocking Services
         1.2.6 Training Services
         1.2.7 Carrier Identification Codes

       1.3 Performance Measurements

                      SECTION 2. ORDERING AND PROVISIONING

2.1 GENERAL BUSINESS REQUIREMENTS
         2.1.1 Ordering and Provisioning Parity
         2.1.2 Local Carrier Service Center (LCSC)/Single Point of Contact
               (SPOC)
         2.1.3 Street Address Guide (SAG)
         2.1.4 CLASS and Custom Features
         2.1.5 Subscriber Payment History
         2.1.6 Carrier Selection
         2.1.7 Notification to Long Distance Carrier
         2.1.8 Number Administration/Number Reservations

2.2 SERVICE ORDER PROCESS REQUIREMENTS
         2.2.1 OBF Compliance
         2.2.2 Service Migrations and New Subscriber Additions


                                                             Attachment VIII - i
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

         2.2.3 Intercept Treatment and Transfer of Service Announcements
         2.2.4 Desired Due Date (DDD)
         2.2.5 Subscriber Premises Inspections and Installations
         2.2.6 Firm Order Confirmation (FOC)
         2.2.7 Order Rejections
         2.2.8 Service Order Changes
         2.2.9 Jeopardy Situations
         2.2.10 Cooperative Testing
         2.2.11 Service Suspensions/Restorations
         2.2.12 Disconnects
         2.2.13 Order Completion Notification
         2.2.14 Fulfillment Process
         2.2.15 Specific Unbundling Requirements

2.3 SYSTEMS INTERFACES AND INFORMATION EXCHANGES
         2.3.1 General Requirements
         2.3.2 Ordering and Provisioning for Resale Services
         2.3.3 Ordering and Provisioning for Unbundling

2.4 STANDARDS
         2.4.1 General Requirements

2.5      PERFORMANCE MEASUREMENTS AND REPORTING 2.5.1 Cycle Time Measurements
         2.5.2 Quality Measurements 2.5.3 Reporting 2.5.4 Provisioning DMOQs

                  SECTION 3. CONNECTIVITY BILLING AND RECORDING

3.1 PROCEDURES

3.2 INFORMATION EXCHANGE AND INTERFACES

3.3 STANDARDS

3.4 PERFORMANCE MEASUREMENTS & REPORTING

                  SECTION 4. PROVISION OF SUBSCRIBER USAGE DATA

4.1 PROCEDURES
         4.1.1 General
         4.1.2 Charges
         4.1.3 Central Clearinghouse & Settlement
         4.1.4 Lost Data
         4.1.5 Testing, Changes and Controls


                                                            Attachment VIII - ii
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

4.2 INFORMATION EXCHANGE AND INTERFACES
         4.2.1 Core Billing Information
         4.2.2 Supporting Billing Information
         4.2.3 Product/Service Specific

4.2.4 EMERGENCY INFORMATION
         4.2.5 Rejected Recorded Usage Data
         4.2.6 Interfaces
         4.2.7 Formats & Characteristics
         4.2.8 Controls

4.3 STANDARDS

4.4 PERFORMANCE MEASUREMENTS

4.5 REPORTING

                                    SECTION 5. MAINTENANCE

5.1 GENERAL REQUIREMENTS

5.2 SYSTEMS INTERFACES AND INFORMATION EXCHANGES

5.3 STANDARDS

5.4 PERFORMANCE MEASUREMENTS AND REPORTING
         5.4.1 Cycle Time Measurements
         5.4.2 Quality
         5.4.3 Reporting

                 SECTION 6. MISCELLANEOUS SERVICES & FUNCTIONS
6.1 General Requirements

         6.1.1 Basic 911 and E911 General Requirements
         6.1.2 Directory Assistance Service
         6.1.3 Operator Services
         6.1.4 Directory Assistance and Listings Service Requests
         6.1.5 Directory Listings General Requirements
         6.1.6 Directory Assistance Data

6.2 SYSTEMS INTERFACES AND EXCHANGES
         6.2.1 Basic 911 and E911 Information Exchanges and Interfaces
         6.2.2 Directory Assistance Data Information Exchanges and Interfaces

                                                           Attachment VIII - iii
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

SECTION 1. GENERAL BUSINESS REQUIREMENTS

1.1 PROCEDURES

The parties will support machine-to-machine interface for maintenance,
preordering and provisioning with the introduction of an industry standard that
is subsequently approved by both parties. The parties further agree to make
every effort to implement EBI within 12 months of the introduction, and joint
approval, of such applicable industry standard or the activation of EBI for
access ordering, whichever is later. MCI further agrees to accept on an interim
basis, until such time as EBI is implemented, the interfaces approved by
BellSouth.

         1.1.1    BellSouth Contact with Subscribers

                  1.1.1.1 MCIm at all times shall be the primary contact and
                  account control for all interactions with its subscribers,
                  except as specified by MCIm. MCIm subscribers include active
                  MCIm subscribers as well as those for whom service orders are
                  pending.

                  1.1.1.2 BellSouth shall ensure that any BellSouth personnel
                  who may receive subscriber inquiries, or otherwise have
                  opportunity for subscriber contact: (i) provide appropriate
                  referrals and telephone numbers to subscribers who inquire
                  about MCIm services or products; (ii) do not in any way
                  disparage or discriminate against MCIm, or its products or
                  services; and (iii) do not provide information about BellSouth
                  products or services during that same inquiry or subscriber
                  contact.

                  1.1.1.3 BellSouth shall not use MCIm's request for subscriber
                  information, order submission, or any other aspect of MCIm's
                  processes or services to aid BellSouthAE s marketing or sales
                  efforts.

         1.1.2    Expedite, Escalation, and Disaster Procedures

                  1.1.2.1 No later than sixty (60) days after the Effective Date
                  of this Agreement, BellSouth and MCIm shall develop mutually
                  acceptable escalation and expedite procedures which may be
                  invoked at any point in the Service Ordering, Provisioning,
                  Maintenance, and Subscriber Usage Data transfer processes to
                  facilitate rapid and timely resolution of

                                                            Attachment VIII -- 1
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  disputes. Such procedures may include, without limitation,
                  intercompany contacts lists for purposes of handling
                  subscriber and other matters which require
                  attention/resolution outside of normal business procedures
                  within sixty (60) days after the Effective Date of this
                  Agreement.

                  1.1.2.2 BellSouth and MCIm agree to jointly develop and
                  implement a detailed service restoration plan and disaster
                  recovery plan to be in effect by year end 1997. A joint task
                  team will commence development within 30 days of execution of
                  this Agreement for implementation throughout 1997, reaching
                  full deployment by year end 1997.

                  Such plans shall incorporate BellSouth's Emergency
                  Contingency Plans for Residence and Business Repair centers.
                  The Plans shall conform to the FCC Restoration Guidelines, to
                  the NSEP (National Security Emergency Preparedness) procedures
                  and adhere to the guidelines developed by the TSP
                  (Telecommunications Service Priority) System office with the
                  NCS (National Communication System) Agency.

                  The Plans shall include at a minimum: (i) provision for
                  immediate access by MCIm via the Electronic Interface to be
                  established pursuant to Section 3, to information indicating
                  the existence, location and source of any emergency network
                  outage affecting MCIm customers; (ii) establishment of a
                  single point of contact responsible for initiating and
                  coordinating the restoration of all Local Services and Network
                  Elements or Combinations; (iii) methods and procedures to
                  provide MCIm with real-time access to information relating to
                  the status of restoration efforts and problem resolution
                  during the restoration process; (iv) an inventory and
                  description of mobile restoration equipment by locations; (v)
                  methods and procedures for the dispatch of mobile equipment to
                  the restoration site; (vi) methods and procedures for
                  re-provisioning all Local Services and Network Elements or
                  Combinations after initial restoration; (vii) equal priority,
                  as between MCIm subscribers and BellSouth subscribers, for
                  restoration efforts, consistent with FCC Service Restoration
                  guidelines, including, without limitation, deployment of
                  repair personnel and access to spare parts and components; and
                  (viii) a mutually agreeable process for escalation of
                  maintenance problems, including a


                                                            Attachment VIII -- 2
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  complete up-to-date list of responsible contacts, available
                  twenty-four (24) hours per day, seven (7) days per week.

                  Said plans shall be modified and updated as necessary. For
                  purposes of this subsection, an emergency network outage is
                  defined as 5,000 or more blocked call attempts in a ten (10)
                  minute period in a single exchange.

         1.1.3    Operational and Technological Changes

                  1.1.3.1 BellSouth shall use its best efforts to notify MCIm of
                  any operational or technological (e.g., central office switch,
                  transmission, systems interfaces) changes six (6) months in
                  advance, or at the time the decision is made, whichever is
                  less. If notice is given to MCIm less than six (6) months in
                  advance, BellSouth will work with MCIm to develop a mutually
                  agreeable implementation plan, if requested by MCIm. MCIm
                  agrees that it shall not submit an unreasonable request.

         1.1.4    Subscriber of Record

                  1.1.4.1 BellSouth shall recognize MCIm as the Subscriber of
                  Record for all Network Elements or services for resale ordered
                  by MCIm and shall send all notices, invoices, and information
                  which pertain to such ordered services directly to MCIm. MCIm
                  will provide BellSouth with addresses to which BellSouth shall
                  send all such notices, invoices, and information.

         1.1.5    Work Center Interface Procedures

                  1.1.5.1 BellSouth and MCIm shall, within 60 days of the
                  Effective Date of this Agreement, develop and implement Work
                  Center (Local Carrier Service Center) Interface Procedures for
                  each function/business process.

1.2 SERVICE OFFERINGS

         1.2.1    Changes in Retail Service Offerings 1.2.1.1 BellSouth shall
                  notify MCIm of any proposed changes in the terms and
                  conditions under which BellSouth offers Telecommunications
                  Services to subscribers who are not Telecommunications Service
                  providers or carriers,

                                                            Attachment VIII -- 3
<PAGE>

           McCImetro - BellSouth Mississippi Interconnection Agreement

                  including, but not limited to, the introduction or
                  discontinuance of any features, functions, services,
                  promotions, or changes in retail rates at least forty-five
                  (45) days prior to the effective date of such change, or
                  concurrent with BellSouth's internal notification process for
                  such change. MCIm recognizes that certain revisions may occur
                  between the time BellSouth notifies MCIm of a change pursuant
                  to this Section and BellSouth's tariff filing of such change.
                  BellSouth shall notify MCIm of such revisions consistent with
                  BellSouth's internal notification process but MCIm accepts
                  the consequences of such mid-stream changes as an uncertainty
                  of doing business and therefore will not hold BellSouth
                  responsible for any resulting inconvenience or cost incurred
                  by MCIm.

                  1.2.1.2 BellSouth shall notify MCIm of any proposed changes in
                  the terms and conditions under which it offers unbundled
                  Network Elements including, but not limited to, the
                  introduction or discontinuance of any features, functions,
                  services, promotions, or changes in rates at least forty-five
                  (45) days prior to the effective date of such change, or
                  concurrent with BellSouth's internal notification process for
                  such change. MCIm recognizes that certain revisions may occur
                  between the time BellSouth notifies MCIm of a change pursuant
                  to this Section and BellSouth's tariff filing of such change.
                  BellSouth shall notify MCIm of such revisions consistent with
                  BellSouth's internal notification process but MCIm accepts
                  the consequences of such mid-stream changes as an uncertainty
                  of doing business and therefore will not hold BellSouth
                  responsible for any resulting inconvenience or cost incurred
                  by MCIm.

         1.2.2    Telephone Service Priority

                  1.2.2.1 Upon receipt of a request from MCIm containing the
                  appropriate TSP Authorization Codes assigned by the NSEP-TSP,
                  BellSouth shall identify the account with this code. BellSouth
                  will conform to the framework defined by the NSEP-TSP for
                  restoration on a priority basis of the individual accounts.

         1.2.3    Caller ID

                  1.2.3.1 To the extent BellSouth is authorized to do so,
                  BellSouth shall cooperate with MCIm to provide the

                                                            Attachment VIII -- 4
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  BellSouth-approved equipment vendor list associated with
                  Caller ID.

         1.2.4 TTY/TDD

                  1.2.4.1 BellSouth shall cooperate with MCIm to provide
                  services and equipment necessary to serve TTY/TDD subscribers.

         1.2.5 Blocking Services

         Upon request from MCIm, BellSouth shall provide blocking of 700, 900,
         and 976 services, or other services of similar type as may now exist or
         be developed in the future, and shall provide Billed Number Screening
         (BNS), including required LIDB updates, or equivalent service for
         blocking completion of bill -to- third party and collect calls, on a
         line, trunk, or individual service basis.

         1.2.6 Training Support

                  1.2.6.1 BellSouth shall develop and deliver training for all
                  BellSouth employees who may communicate with MCIm subscribers.
                  Training will be provided for all ordering, provisioning,
                  maintenance, billing, miscellaneous services, and any other
                  area which is appropriate for the services to be provided by
                  BellSouth pursuant to this Agreement.

                  1.2.6.2 BellSouth will initially train MCIm employees on the
                  utilization of electronic interfaces and operational interface
                  procedures with BellSouth support centers for ordering,
                  maintenance and provisioning. BellSouth will provide the
                  initial training and training due to significant BellSouth
                  system or interface changes to MCIm at no charge.

         1.2.7 Carrier Identification Codes

         BellSouth shall provide to MCIm the active Carrier Identification Codes
         (CIC) for both Dial 1 and 800 services for each of its access tandems
         on a one time basis in accordance with OBF standards.

1.3 Performance Measurements

         1.3.1 BellSouth, in providing Services and Elements to MCIm
         pursuant to this Agreement, shall provide MCIm the same quality of
         service that BellSouth provides itself and its end-users. This

                                                            Attachment VIII -- 5
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

         Agreement includes MCIm's measurements for those requirements. The
         Parties have agreed to five (5) categories of Performance to be
         measured: (1) Ordering and Provisioning ; (2) Connectivity Billing; (3)
         Subscriber Usage Data; (4) Maintenance; and (5) LIDB. Each category
         includes measurements which focus on timeliness, accuracy and quality.
         BellSouth shall measure the following activities to meet the goals
         provided herein.

         1.3.2 Except as otherwise provided in this Agreement, BellSouth shall
         provide data on a monthly basis for each state and for the nine states
         served by BellSouth. The data shall be reported to MCIm In a mutually
         agreed upon format which will enable MCIm to compare BellSouth's
         performance for itself with respect to a specific measure to
         BellSouth's performance for MCIm for that same specific measure.
         BellSouth shall also provide the raw data used to calculate each
         measurement for MCIm as reasonably requested by MCIm. For provisioning
         and maintenance, separate measurements shall be provided as follows:

         o POTS/Non-Design

                  - Residence - Dispatch Out/Non-Dispatch Out
                  - Business - Dispatch Out/Non-Dispatch Out

         o UNE - Dispatch Out/Non-Dispatch Out
         o Local lnterconnection/Trunking
         o Specials - Design Only

         1.3.3 BellSouth and MCIm recognize that percentage target certain
         performance levels and data have not been provided for all measurements
         and that such targets for certain categories of performance will be
         required to improve performance, to maintain parity with that which
         BellSouth has obligated itself to provide under this Agreement, or to
         improve service as MCIm and BellSouth may mutually agree. BellSouth and
         MCIm agree to meet and to discuss establishment of such targets
         quarterly, starting no later than ninety (90) days after actual
         performance occurs. Notwithstanding the foregoing, MCIm reserves its
         rights to request targets that exceed parity. Such a request may
         require MCIm to reimburse BellSouth for the reasonable and demonstrable
         cost BellSouth incurs to provide such performance, as the Parties may
         mutually agree.

                                                            Attachment VIII -- 6
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

Section 2. Ordering and Provisioning

         2.1 General Business Requirements

                  2.1.1    Ordering and Provisioning Parity

                           2.1.1.1 For preordering and provisioning, the parties
                           agree to implement the BellSouth approved and
                           implemented EBI standard for Local Service Requests
                           ("LSR") within 12 months of the implementation of the
                           EBI interface for Access Service Request
                           provisioning. MCI further agrees to accept on an
                           interim basis, until such time as EBI is implemented
                           for LSR, the interfaces approved by BellSouth.

                           2.1.1.2 During the term of this Agreement, BellSouth
                           shall provide necessary ordering and provisioning
                           business process support as well as those technical
                           and systems interfaces as may be required to enable
                           MCIm to provide at least the same level and quality
                           of service for all resale services, functions,
                           features, capabilities and unbundled Network Elements
                           as BellSouth provides itself, its Affiliates or its
                           own subscribers. BellSouth shall provide MCIm with
                           the same level of ordering and provisioning support
                           as BellSouth provides itself in accordance with
                           standards and performance measurements that are at
                           least equal to the highest level of standards and/or
                           performance measurements that BellSouth uses and/or
                           which are required by law, regulatory agency, or by
                           BellSouthAE s own internal procedures, whichever are
                           the most rigorous. These standards shall apply to the
                           quality of the technology, equipment, facilities,
                           processes, and techniques (including, but not limited
                           to, such new architecture, equipment, facilities, and
                           interfaces as BellSouth may deploy) that BellSouth
                           provides to MCIm under this Agreement.

                           For resale purposes, BellSouth shall provide real
                           time electronic interfaces ("EI") for transferring
                           and receiving Service Orders and Provisioning data
                           and materials (e.g., access to Street Address Guide
                           ("SAG") and Telephone Number Assignment database).
                           These interfaces shall be administered through a
                           gateway that will serve as a point of contact for the
                           transmission of such data from MCIm to BellSouth, and
                           from BellSouth to MCIm. The implementation of such
                           data transfer system shall be negotiated in good
                           faith by the parties and be specified in a

                                                            Attachment VIII -- 7
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  written agreement between MCIm and BellSouth that will be
                  completed expeditiously after the Effective Date of this
                  Agreement. MCIm and BellSouth agree to use best efforts to
                  provide the Electronic Communications gateway described above
                  as soon as practicable, but in no event later than April 1,
                  1997. In addition, (I) BellSouth agrees to use its best
                  efforts to carry outs its responsibilities under this Section,
                  and (ii) MCIm agrees to use its best efforts to carry out its
                  responsibilities under this Section interfaces. BellSouth
                  warrants that interim solutions shall provide MCIm Customers
                  with the same level of service available to BellSouth
                  customers.

         2.1.2    Local Carrier Service Center (LCSC)/Single Point of Contact
                  (SPOC)

         BellSouth shall provide MCIm, twenty-four (24) hours a day, seven (7)
         days a week, with the capability of ordering via an electronic
         interface, except for scheduled electronic interface downtime and
         mutually agreed in advance electronic interface downtime. Provisioning
         shall be available during normal business hours. Downtime shall not be
         scheduled during normal business hours and shall occur during time
         where systems experience minimal usage. BellSouth shall provide a
         Single Point of Contact (SPOC) for all ordering and provisioning
         contacts and order flow involved in the purchase and provisioning of
         BellSouth's unbundled Elements, Combinations and Resale. BellSouth's
         SPOC shall provide to MCIm a toll-free nationwide telephone number
         (operational from 8:30 a.m. to 5:00 p.m., Monday through Friday, within
         each respective continental U.S. time zone) which will be answered by
         capable staff trained to answer questions and resolve problems in
         connection with the ordering and provisioning of Elements or
         Combinations and resale services.

         2.1.3    Street Address Guide (SAG)

                  2.1.3.1 Within thirty (30) days after the Effective Date of
                  this Agreement, BellSouth shall provide to MCIm the SAG data,
                  or its equivalent, in electronic form. All changes to the SAG
                  shall be made available to MCIm on the same day as the change
                  to the data is made.

         2.1.4    CLASS and Custom Features

                  2.1.4.1 For purchase of unbundled network elements, MCIm


                                                            Attachment VIII -- 8
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  may order the entire set of CLASS and Custom features and
                  functions, or, where Technically Feasible, a subset of any one
                  or any combination of such features. For resale purposes,
                  BellSouth shall provide MCIm with a list of features and
                  functions available on an end office by end office basis.

         2.1.5    SUBSCRIBER PAYMENT HISTORY

                  2.1.5.1 To the extent each party has such information, MCIm
                  and BellSouth agree to make available to each other such of
                  the following subscriber information as the subscriber
                  authorizes BellSouth or MCIm to release:

                  2.1.5.1.1 Applicant's name;

                  2.1.5.1.2 Applicant's address;

                  2.1.5.1.3 Applicant's previous phone number, if any;

                  2.1.5.1.4 Amount, if any, of unpaid balance in
                  applicant's name;

                  2.1.5.1.5 Whether applicant is delinquent on
                  payments;

                  2.1.5.1.6 Length of service with prior local or
                  intraLATA toll provider;

                  2.1.5.1.7 Whether applicant had local or intraLATA toll
                  service terminated or suspended within the last six months
                  with an explanation of the reason therefor; and,

                  2.1.5.1.8 Whether applicant was required by prior local or
                  intraLATA toll provider to pay a deposit or make an advance
                  payment, including the amount of each.

         2.1.5.2 BellSouth shall not refuse service to MCIm for any potential
         MCIm subscriber on the basis of that subscriberAE s past payment
         history with BellSouth. MCIm shall establish the credit scoring
         criteria for applicants for MCIm services.

         2.1.5.3 Left Blank Intentionally.

                                                            Attachment VIII -- 9
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  2.1.5.4 Left Blank Intentionally.

         2.1.6    Carrier Selection

                  2.1.6.1 For services for resale or unbundled Network Elements,
                  BellSouth shall provide to MCIm, no later than January 1,
                  1997, the capability to order local service, intraLATA (where
                  available), interLATA, and international toll services by
                  entering the MCIm subscriber' s choice of carrier on a single
                  order. BellSouth shall provide MCIm with the capability to
                  order separate interLATA and intraLATA (where available)
                  carriers on a line or trunk basis.

                  2.1.6.2 Where intraLATA toll carrier selection is not
                  implemented, BellSouth agrees to provide intraLATA toll
                  services for resale to MCIm. In all other cases, BellSouth
                  will route toll calls to the appropriate carrier as designated
                  by MCIm.

         2.1.7    Notification to Long Distance Carrier

                  2.1.7.1 BellSouth agrees to notify MCI using OBF-approved CARE
                  transactions, whenever an MCI subscriber who is provided local
                  service through services for resale or unbundled Network
                  Elements changes MCI PIC status.

                  2.1.7.2 BellSouth shall support and implement new Transaction
                  Code Status Indicators (TCSIs) defined by OBF in support of
                  local resale to enable MCI to provide seamless subscriber
                  service.

                           2.1.7.2.1 BellSouth shall implement TCSIs used in
                           conjunction with the new Local Service Provider (LSP)
                           Identification Code, where applicable, for handling
                           Account Maintenance, Subscriber Service, and Trouble
                           Administration issues. These TCSIs include
                           4001/02/05, 4201-4205, 4301, 2033, 2233, 3147, 3148,
                           3149, and others as OBF may define.

                           2.1.7.2.2 In addition, BellSouth shall implement
                           TCSIs used in conjunction with the new Ported
                           Telephone Number field to link "shadow" and ported
                           telephone numbers in support of Interim Number
                           Portability. These TCSIs may include 2231, 3150,


                                                           Attachment VIII -- 10
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                  3151, and others as OBF may define.

                  2.1.7.3 Where available, BellSouth shall provide to MCI the
                  Local Service Provider ID (LSP) on purchased lists of MCI
                  PICAE d and non-PIC'd subscribers.

                  2.1.7.4 Where available, BellSouth shall provide the Ported
                  Telephone Number (PTN) on purchased CARE lists of MCI PIC'd
                  and non-MCI PIC'd subscribers.

         2.1.8    Number Administration/Number Reservations

                  2.1.8.1. Until Number Administration functions are assumed by
                  a neutral third party in accordance with FCC Rules and
                  Regulations, BellSouth shall assign NXXs to MCIm on a
                  non-discriminatory basis in accordance with national
                  guidelines. BellSouth shall provide the same range of number
                  choices allowing the assignment of numbers while the
                  subscriber is on the phone to MCIm, including choice of
                  exchange number, as BellSouth provides its own subscribers.
                  Reservation and aging of numbers shall remain BellSouth's
                  responsibility.

                  2.1.8.2 Where MCIm has not obtained its own NXX, BellSouth
                  shall reserve up to 100 telephone numbers, per MCIm request,
                  per NPA-NXX (where available), for large business subscribers
                  in the same manner as for BellSouth's own large business
                  subscribers. BellSouth shall provide additional numbers at
                  MCIm' s request as subscriber demand requires. Telephone
                  numbers reserved in this manner may be released for other than
                  MCIm use only in the same manner that BellSouth would release
                  numbers reserved for its own subscribers.

                  2.1.8.3 Where MCIm has obtained its own NXX, but has purchased
                  BellSouth services for resale or Network Elements, BellSouth
                  agrees to install the MCIm NXX in BellSouth's switch
                  according to the local calling area defined by BellSouth and
                  perform appropriate number administration functions. Where
                  MCIm provides its own switching and obtains its own NXX code,
                  BellSouth agrees to install the routing in its switches
                  according to the local calling area defined by MCI.

                                                           Attachment VIII -- 11
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  2.1.8.4 BellSouth shall accept MCIm orders with assigned
                  vanity numbers and blocks of numbers assigned for use with
                  complex services including, but not limited to, DID,
                  MULTISERV, and Hunting arrangements. Vanity numbers and
                  numbers for use with complex services, DID and Hunting
                  arrangements will be assigned by the LCSC on a case-by-case
                  basis to meet the needs for specific service order activity.

                  2.1.8.5 Until the Electronic Interface exists for simple
                  services number reservations, BellSouth shall use its best
                  efforts to provide confirmation of a number reservation within
                  twenty-four (24) hours of receiving a completed MCIm's
                  request. For reservations associated with complex services see
                  2.1.8.4.

2.2 SERVICE ORDER PROCESS REQUIREMENTS

         2.2.1 OBF Compliance

                  2.2.1.1 In accordance with OBF standards, BellSouth and MCIm
                  shall follow the OBF-developed ordering and provisioning
                  process standards. These processes include pre-order service
                  inquiry, pre-order service inquiry response, firm order,
                  acknowledgment/ rejection, firm order confirmation, delay
                  notification, and completion notification. BellSouth agrees to
                  work cooperatively to implement future OBF-developed processes
                  related to ordering and provisioning.

         2.2.2 Service Migrations and New Subscriber Additions

                  2.2.2.1 For resale services, BellSouth shall not require a
                  disconnect order from a subscriber, another local service
                  provider, or any other entity, to process an MCIm order to
                  establish MCIm Local Service and/or migrate a subscriber to
                  MCIm local service.

                  2.2.2.2 BellSouth shall not intentionally or unnecessarily
                  disconnect any subscriber service or existing features at any
                  time during the migration of a Resale subscriber to MCIm
                  service, unless disconnection is required by an MCIm order
                  changing the service type.

                                                           Attachment VIII -- 12
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  2.2.2.3 For services MCIm will provide through unbundled
                  Network Elements, BellSouth shall, upon receipt of a BellSouth
                  Blanket Agency Agreement Letter for Local Service Provider
                  provided in the Ordering Guidelines, recognize MCIm as an
                  agent for the subscriber in requesting the migration of
                  services provided by another BellSouth or another CLEC. In
                  addition, BellSouth shall not disconnect any BellSouth
                  services provided to the BellSouth subscriber until MCIm
                  notifies BellSouth that MCIm's unbundled elements are
                  installed and operational, except where existing BellSouth
                  facilities are being reused.

                  2.2.2.4 Unless otherwise directed by MCIm, when MCIm orders
                  resale services or Network Elements, where applicable, all
                  trunk or telephone numbers currently associated with existing
                  services shall be retained without loss of feature capability
                  and without loss of associated ancillary services, except
                  those excluded from resale, partial migration of lines or
                  services affected by the MCIm order which require common
                  blocks of equipment or facilities (e.g. MultiServ, Hunting,
                  DID), and BellSouth Handicap Exemptions shall be retained.
                  BellSouth shall not intentionally or unnecessarily interrupt
                  feature capability including, but not limited to, Directory
                  Assistance and 911/E911 capability.

                  2.2.2.5 For subscriber conversions requiring coordinated
                  cut-over activities, on a per order basis, BellSouth and MCIm
                  will agree on a scheduled conversion time.

                           2.2.2.5.1 BellSouth will coordinate activities of all
                           BellSouth work groups involved.

                           2.2.2.5.2 BellSouth will notify MCIm when conversion
                           is complete.

                           2.2.2.5.3 BellSouth will use its best efforts to
                           minimize subscriber interruptions during conversions.

         2.2.3 Intercept Treatment and Transfer of Service Announcements

                  2.2.3.1 BellSouth shall provide the same unbranded
                  intercept treatment and transfer of service announcements
                  to MCIm's subscribers. for resale and unbundled switch as
                  BellSouth provides its own end users.

                                                           Attachment VIII -- 13
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

         2.2.4 Desired Due Date (DDD)

                  2.2.4.1 MCIm shall specify on each order the Desired Due Date
                  (DDD). BellSouth shall not complete the order prior to DDD
                  unless early turn-up is needed for testing purposes. BellSouth
                  will provide services on the DDD, or on the earliest available
                  installation date thereafter. BellSouth will notify MCIm if
                  the DDD cannot be met.

                  2.2.4.2 If the DDD falls after the standard order completion
                  interval provided by BellSouth, then BellSouth, where
                  facilities are available, shall complete the order on the
                  Desired Due Date.

                  2.2.4.3 BellSouth shall supply MCIm with due date intervals to
                  be used by MCIm personnel to determine service installation
                  dates.

                  2.2.4.4 Subsequent to an initial order submission, MCIm may
                  require a new/revised due date that is earlier than the
                  original due date requested. BellSouth will make best effort
                  to meet MCImAE s requested due date, and applicable expedite
                  charges set forth in Attachment I will apply.

                  2.2.4.5 Any special or preferred scheduling options available,
                  internally or externally to BellSouth, for ordering and
                  provisioning services shall also be available to MCIm.

         2.2.5    Subscriber Premises Inspections and Installations -

                  2.2.5.1 MCIm shall perform or contract for all needs
                  assessments, including equipment and installation
                  requirements, at the subscriber premises on the subscriber's
                  side of the demarcation point.

                  2.2.5.2 BellSouth shall provide MCIm with the ability to
                  schedule subscriber premises installations.

                  2.2.5.3 In accordance with BellSouth's procedures and on
                  parity with provision of such services to BellSouth's
                  customers, BellSouth shall provide extended demarcation beyond
                  the NID, at MCIm's request, using intrabuilding riser and
                  lateral beyond the NID.

                                                           Attachment VIII -- 14
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

         2.2.6    Firm Order Confirmation (FOC)

                  2.2.6.1 BellSouth shall provide to MCIm, via an electronic
                  interface, a Firm Order Confirmation (FOC) for each MCIm order
                  provided electronically. The FOC shall contain on a per line
                  and/or trunk basis, where applicable, an enumeration of MCIm's
                  ordered unbundled Network Elements (and the specific
                  BellSouth naming convention applied to that element or
                  combination), features, functions, resale services, options,
                  physical interconnection, quantity, and BellSouth Committed
                  Due Date for order completion.

                  2.2.6.2 For a revised FOC, BellSouth shall provide order
                  detail on a per line or per trunk level as well as the order
                  detail from the prior FOC. BellSouth shall submit, where
                  applicable, to MCIm a complete revised list of features,
                  functions and services ordered.

                  2.2.6.3 BellSouth shall provide to MCIm the date that
                  service is initiated.

         2.2.7    Order Rejections

                  2.2.7.1 BellSouth shall review MCIm local service requests and
                  notify MCIm of all known reasons for which the order was
                  rejected. BellSouth shall not reject any orders due to an
                  unavailable Desired Due Date. In that instance, BellSouth will
                  process the order assigning the best available due date. The
                  assigned due date will be returned to MCIm as the FOC.

                  2.2.7.2 Left blank intentionally

                  2.2.7.3 Left blank intentionally

         2.2.8    Service Order Changes

                  2.2.8.1 If an installation requires deviation for the Service
                  Order in any manner, or if a MCIm customer requests a service
                  change at the time of installation, BellSouth will call MCIm
                  in advance of performing the installation for authorization.
                  BellSouth will provide MCIm at that time an estimate of
                  additional labor hours and/or materials required for that
                  installation. After installation is completed, BellSouth will
                  immediately inform MCIm of actual labor

                                                           Attachment VIII -- 15
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  hours and materials used.

                  2.2.8.1.1 If work performed in connection with a service order
                  is partially completed, notification which identifies the work
                  that was done and work remaining to complete will be provided
                  at the same level BellSouth provides to itself.

                  2.2.8.2 Where BellSouth provides installation and the MCIm
                  Customer requests a service change at the time of
                  installation. BellSouth shall immediately notify MCIm at the
                  telephone number on the service order of that request. The
                  BellSouth technician should notify MCIm in the presence of the
                  MCIm Customer so that MCIm can negotiate authority to install
                  the requested service directly with that customer and the
                  technician and revise appropriate ordering documents as
                  necessary.

         2.2.9    Jeopardy Situations

                  2.2.9.1 BellSouth shall provide to MCIm notification of any
                  jeopardy situations prior to the Committed Due Date, missed
                  appointments and any other delay or problem in completing work
                  specified on MCIm's service order as detailed on the FOC.

         2.2.10   Cooperative Testing

                  2.2.10.1 Network Testing

                           2.2.10.1.1 BellSouth shall perform all pre-service
                           testing prior to the completion of the order,
                           including testing on local service facilities and
                           switch translations, including, but not limited to,
                           verification of features, functions, and services
                           ordered by MCIm.

                           2.2.10.1.2 Within 24-hrs of MCIm's request for
                           scheduled cooperative testing, BellSouth shall
                           perform said testing with MCIm (including trouble
                           shooting to isolate any problems) to test Network
                           Elements purchased by MCIm in order to identify any
                           problems.

                  2.2.10.2 Systems and Process Testing

                                                           Attachment VIII -- 16
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           2.2.10.2.1 LEC shall cooperate with MCIm upon request
                           to test all operational interfaces and processes and
                           thereby ensure that they are in place and functioning
                           properly and efficiently.

         2.2.11   Service Suspensions/Restorations

                  2.2.11.1 Upon MCIm's request through a Suspend/Restore Order,
                  BellSouth shall suspend or restore the functionality of any
                  Network Element, feature, function, or resale service.
                  BellSouth shall use its best efforts to provide restoration
                  priority on a per network element or combination basis in a
                  manner that conforms with MCIm requested priorities.

         2.2.12   Disconnects

                  2.2.12.1 BellSouth shall provide to MCIm daily information
                  notifying MCIm of any services disconnected from MCIm, other
                  than disconnections initiated by MCIm, in a mutually agreed
                  upon format.

         2.2.13   Order Completion Notification

                  2.2.13.1 Upon completion of a service orders associated with
                  Local Service Requests (LSRs) in its system(s), BellSouth
                  shall submit to MCIm an order completion notifications. Such
                  notifications shall provide the Purchase Order Numbers
                  provided by MCIm when submitting the requests and the Local
                  Service Request Numbers assigned by BellSouth.

         2.2.14   Fulfillment Process

                  2.2.14.1 MCIm shall conduct all activities associated with the
                  account fulfillment process, for example welcome packages and
                  calling cards, for all MCIm subscribers.

         2.2.15   Specific Unbundling Requirements

                  2.2.15.1 MCIm may order and BellSouth shall provision
                  unbundled Network Elements either individually or in any
                  combination on a single order. Network Elements ordered as
                  combined shall be provisioned as combined by BellSouth unless
                  MCIm specifies that the Network Elements ordered in
                  combination be provisioned separately. Orders of combined

                                                           Attachment VIII -- 17
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  Network Elements shall be subject to provisions of section 2.3
                  of Attachment III.

                  2.2.15.2 Prior to providing service in a specific geographic
                  area or when MCIm requires a change of network configuration,
                  MCIm may elect to place an order with BellSouth requiring
                  BellSouth to prepare Network Elements and switch translations
                  in advance of orders for additional network elements from
                  MCIm.

                  2.2.15.3 When MCIm orders Network Elements or Combinations
                  that are currently interconnected and functional, Network
                  Elements and Combinations shall remain connected and
                  functional without any disconnection or disruption of
                  functionality. This shall be known as Contiguous Network
                  Interconnection of Network Elements.

                  2.2.15.4 Order combinations of Contiguous Network Elements
                  shall be available to be ordered (i) on a case-by-case basis
                  for those Network Elements that are subscriber-specific; or
                  (ii) on a common-use basis for those Network Elements that are
                  shared by multiple subscribers.

                  2.2.15.5 Network Elements shall be identified and ordered by
                  MCIm so that they can be provisioned together. MCIm may
                  specify the functionality of a combination without the need to
                  specify the configuration of the individual Network Elements
                  needed to provide that functionality.

                  2.2.15.6 When ordering a Combination, MCIm shall have the
                  option of ordering all features, functions and capabilities of
                  each Network Element.

                  2.2.15.7 When MCIm orders Network Elements, BellSouth shall
                  provision at parity with services provided to BellSouth
                  subscribers all features, functions, and capabilities of the
                  Network Elements which include, but are not limited to:

                           2.2.15.7.1 The basic switching function of connecting
                           lines to lines, lines to trunks, trunks to lines, and
                           trunks to trunks, as well as the same basic
                           capabilities made available to BellSouth's
                           subscribers, such as telephone number, white page
                           listing, and dial tone; and

                                                           Attachment VIII -- 18
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           2.2.15.7.2 All other features that the switch is
                           equipped to provide, including, but not limited to,
                           custom calling, custom local area signaling service
                           features, and MULTISERV, as well as any Technically
                           Feasible customized routing functions provided by the
                           switch.

                  2.2.15.8 When MCIm orders Network Elements, BellSouth shall
                  provide technical assistance to ensure compatibility between
                  elements.

                  2.2.15.9 Each order for Network Elements will contain
                  administration, bill, contact, and subscriber information, as
                  defined by the OBF.

2.3 SYSTEMS INTERFACES AND INFORMATION EXCHANGES

         2.3.1    General Requirements

                  2.3.1.1 For pre-ordering and provisioning, the parties agree
                  to implement the BellSouth approved and implemented EBI
                  standard for Local Service Requests (LSR") within twelve (12)
                  months of the implementation of the EBI interface for Access
                  Service Request provisioning. MCIm further agrees to accept on
                  an interim basis, until such time as EBI is implemented for
                  LSR, the interfaces approved by BellSouth. These interim
                  solutions described below address the Pre-ordering, Ordering
                  and Provisioning interfaces.

                           2.3.1.1.1 Until such standards are completed,
                           BellSouth and MCIm agree to use an interim order
                           format and interface which will be defined by
                           BellSouth and implementation negotiated between the
                           Parties no later than sixty (60) days after the
                           Effective Date of this Agreement.

                  2.3.1.2 BellSouth interfaces shall provide MCIm with the same
                  process and system capabilities for both Residence and
                  Business ordering and provisioning. MCIm shall not be required
                  to develop distinct processes or interfaces by class of
                  service.

                  2.3.1.3 BellSouth and MCIm shall agree on and implement
                  interim solutions for each interface within thirty (30) days
                  after the Effective Date of this Agreement, unless otherwise

                                                           Attachment VIII -- 19
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           specified in Exhibit A of this Attachment. The
                           interim interface(s) shall, at a minimum, provide
                           MCIm the same functionality and level of service as
                           is currently provided by the electronic interfaces
                           used by BellSouth for its own systems, users, or
                           subscribers.

                           2.3.1.4 Interim interfaces or processes may be
                           modified, if so agreed by MCIm and BellSouth, during
                           the interim period.

                           2.3.1.5 Until the electronic interface is available,
                           BellSouth agrees that the Local Carrier Service
                           Center (LCSC) or similar function will accept MCIm
                           orders. Orders will be transmitted to the LCSC via an
                           interface or method agreed upon by MCIm and
                           BellSouth.

                           2.3.1.6 BellSouth shall provide to MCIm a list of all
                           CLASS and Custom features and functions within ten
                           (10) days of the Effective Date of this Agreement and
                           shall provide updates to such list at the time new
                           features and functions become available.

                   2.3.2   Ordering and Provisioning for Resale Services

                           2.3.2.1 BellSouth shall make available to MCIm a list
                           of all intraLATA and interLATA carriers available for
                           subscriber selection on a central office level.

                           2.3.2.2 Left blank intentionally.

                           2.3.2.3 BellSouth shall provide MCIm with customer
                           service records, including without limitation
                           Customer Proprietary Network Information (CPNI),
                           except such information as BellSouth is not
                           authorized to release either by the customer or
                           pursuant to applicable law, rule or regulation.

                                    2.3.2.3.1 BellSouth shall provide to MCIm,
                                    on a restricted basis which will
                                    appropriately safeguard "subscribers'"
                                    privacy, a real-time, electronic interface
                                    to "BellSouth's" subscriber information
                                    systems which will allow MCIm to obtain the
                                    subscriber profile information, including
                                    listed name, billing and service addresses,
                                    billed telephone number(s), and
                                    identification of features and services on
                                    the "subscriber's" account(s). The Parties
                                    shall mutually

                                                           Attachment VIII -- 20
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    agree on restrictions that will
                                    appropriately safeguard subscribers'
                                    privacy.

                                            2.3.2.3.1.1 Until access to CSRs is
                                            available via a real-time,
                                            electronic interface, BellSouth
                                            shall provide CSRs via a three-way
                                            call to a BellSouth service center
                                            or will fax a copy of the
                                            customer's record to MCIm with the
                                            customer's permission. BellSouth
                                            will also make available to MCIm the
                                            "switch-as-is" process. BellSouth
                                            will also provide information on an
                                            existing account in conjunction with
                                            issuing an LSR to convert the
                                            subscriber's service to MCIm.

                                            2.3.2.3.1.2 BellSouth shall not
                                            require MCIm to present to BellSouth
                                            prior written authorization from
                                            each customer before BellSouth
                                            allows MCIm access to CSRs. Instead,
                                            MCIm shall issue a blanket letter of
                                            authorization to BellSouth which
                                            states that MCIm will obtain the
                                            customer's permission before
                                            accessing the CSRs.

                  2.3.2.4 BellSouth shall provide to MCIm access to a list of
                  all Telecommunications Services features and functions,
                  including new services, trial offers, and promotions. At
                  MCIm's option, BellSouth will provide MCIm access to
                  BellSouth's Products and Services Inventory Management System
                  (P/SIMS) data via Network Data Mover file transfer. BellSouth
                  shall update this data at least once a week from BellSouth's
                  P/SIMS database. The data shall be available at all times and
                  MCIm may retrieve the data at any time on a mutually agreed
                  upon schedule which will allow MCIm to download the file once
                  it is updated by BellSouth

                  2.3.2.5 At MCIm's option, BellSouth will provide MCIm the
                  capability to validate addresses by access to "BellSouth's"
                  Regional Street Address Guide (RSAG) via dial-up or LAN to WAN
                  access. Implementation time frames will be negotiated between
                  the parties.

                  2.3.2.6. BellSouth shall provide MCIm on line access to
                  telephone number reservations by April 1, 1997. Until on
                  line access is available via electronic interface, BellSouth

                                                           Attachment VIII -- 21
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           agrees to provide MCIm with a ready supply of
                           telephone numbers as described in Section 2.1.8.2.

                           2.3.2.7 At MCIm's option, BellSouth will provide
                           MCIm the capability to reserve telephone numbers
                           electronically. Up to 100 telephone numbers per
                           CLLI/Terminating Traffic Area may be reserved at
                           MCIm's request, for MCIm's sole use. BellSouth
                           will provide additional numbers manually at MCIm's
                           request in order that MCIm will have sufficient
                           numbers available to meet expected needs. In
                           situations where there are limited numbers available,
                           BellSouth may limit the number of telephone numbers
                           that can be reserved for a particular CLLI/TTA. The
                           telephone number reservations made in this manner are
                           valid for MCIm's assignment for ninety (90) days
                           from the reservation date. BellSouth will make the
                           telephone number reservations available to MCIm via
                           diskette or via electronic file transfer. BellSouth
                           agrees to implement an electronic interface to allow
                           MCIm to reserve telephone numbers via an on-line
                           electronic interface no later than April 1, 1997.

                           2.3.2.8 BellSouth Local Carrier Service Center (LSCS)
                           will assign vanity numbers and blocks of numbers for
                           use with complex services including, but not limited
                           to, DID and Hunting arrangements, as requested by
                           MCIm, and documented in Work Center Interface
                           agreements.

                           2.3.2.9 BellSouth will supply MCIm with Interval
                           Guide Job Aids to be used to determine service
                           installation dates. BellSouth will implement an
                           electronic interface to its Due Date Support
                           Application (DSAP) no later than April 1, 1997.

                           2.3.2.10 BellSouth shall provide to MCIm a real-time,
                           on-line, electronic interface which will allow MCIm
                           the ability to validate addresses, reserve telephone
                           numbers, determine central office services/features
                           and the ability to estimate due dates. This
                           capability shall be provided no later than April 1,
                           1997.

                           2.3.2.11 BellSouth shall provide to MCIm a real-time,
                           on-line electronic interface which will allow for
                           entering Local Service Requests for resold services.
                           This interface will provide MCIm the capability to
                           retrieve Firm Order Confirmation, service order
                           status and completion notifications.

                                                           Attachment VIII -- 22
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           2.3.2.12 BellSouth agrees to develop and make
                           available to MCIm an Electronic Data Interchange
                           (EDI) for ordering Local Services. This EDI ordering
                           process supports select service order types and
                           related transactions (i.e. orders, confirmations,
                           firm order commitments, supplements and completions).

                           2.3.2.13 For ordering of Local Service Requests via
                           EDI, BellSouth agrees to develop the EDI interface to
                           be in conformance with the industry standards at such
                           time as those standards become available.
                           Implementation of this industry standard EDI
                           interface will be per schedules mutually agreed to by
                           MCIm and BellSouth.

                  2.3.3    Ordering and Provisioning for Unbundling

                           2.3.3.1 BellSouth shall provide to MCIm upon request
                           a listing of all technically available
                           functionalities for Network Elements.

                           2.3.3.2 BellSouth shall provide to MCIm upon request
                           all engineering design and layout information for
                           Network Elements.

                           2.3.3.3 BellSouth shall provide to MCIm a real-time,
                           electronic interface which will allow MCIm to
                           determine service due date intervals, schedule
                           appointments, and adjust pending order due dates in
                           real-time.

                           2.3.3.4 BellSouth shall provide to MCIm upon request
                           advance information of the details and requirements
                           for planning and implementation of NPA splits at
                           least 6 months prior to implementation of the split.

                           2.3.3.5 BellSouth shall provide to MCIm information
                           on charges associated with special construction.
                           Until real-time, electronic interface is available,
                           BellSouth agrees that BellSouth will immediately
                           notify MCIm of any charges associated with necessary
                           construction.

                           2.3.3.6 BellSouth shall provide MCIm with results
                           from mechanized loop tests.

                           2.3.3.7 BellSouth shall provide MCIm with
                           confirmation of circuit assignments.

                                                           Attachment VIII -- 23
<PAGE>

           MCimetro - BellSouth Mississippi Interconnection Agreement

         2.4 STANDARDS

                  2.4.1 General Requirements

                           2.4.1.1 MCIm and BellSouth shall use the OBF
                           standards for ordering and provisioning codes to be
                           used for Network Elements. These codes shall apply to
                           all aspects of the unbundling of elements and shall
                           be known as data elements as defined by the
                           Telecommunications Industry Forum Electronic Data
                           Interchange Service Order Subcommittee
                           (TCIF-EDI-SOSC). Some unbundled Network Elements will
                           continue to be ordered utilizing the ASR process.

         2.5 PERFORMANCE MEASUREMENTS AND REPORTING: Provisioning
         performed by BellSouth will meet the following measurements:

                  2.5.1 Desired Due Date: Measures as a percent how often
                  BellSouth is able to meet MCIm's desired due date for
                  provisioning Services, Elements, or Combinations. BellSouth
                  has stated that it cannot provide this measurement at this
                  time. The Parties agree to review BellSouth's ability to
                  provide Desired Due Date no later than October 1, 1997. Until
                  such time as BellSouth provides this measurement, BellSouth
                  agrees to provide a range of intervals provided below that it
                  represents are reflective of the time it takes to install
                  Services, Elements, or Combinations. BellSouth shall measure
                  and provide data on the performance intervals (for each of
                  BellSouth and MCIm Customers) and the Parties agree to meet to
                  review interval data to assess whether the Intervals should be
                  improved, no later than August 1, 1997. In addition, BellSouth
                  and MCIm shall jointly develop by July 1, 1997, an audit plan
                  that will provide data to demonstrate that the intervals
                  provided by BellSouth to MCIm are at parity with those
                  BellSouth provided itself or its end-users.

                                                           Attachment VIII -- 24
<PAGE>

           MCimetro - BellSouth Mississippi Interconnection Agreement

--------------------------------------------------------------------------------
                  SERVICE                               INTERVAL
--------------------------------------------------------------------------------
INSTALLATION
--------------------------------------------------------------------------------
Lines/trunks With no premises visit:
--------------------------------------------------------------------------------
BUSINESS
--------------------------------------------------------------------------------
    1-3 Lines                                   (less than or equal to) 2
                                                business days*
--------------------------------------------------------------------------------
    3-5 Lines                                   (less than or equal to) 4
                                                business days*
--------------------------------------------------------------------------------
    Over 15 lines                               As NEGOTIATED
--------------------------------------------------------------------------------
RESIDENTIAL                                     (less than or equal) to 2
                                                business days*
--------------------------------------------------------------------------------
Lines/Trunks with premises visit:
--------------------------------------------------------------------------------
BUSINESS
--------------------------------------------------------------------------------
    1-2 lines                                   2 business days*
--------------------------------------------------------------------------------
    3-5 lines                                   4 business days*
--------------------------------------------------------------------------------
   6-10 lines                                   6 business days*
--------------------------------------------------------------------------------
   11-15 lines                                  9 business days*
--------------------------------------------------------------------------------
   Over 15 lines                                AS NEGOTIATED
--------------------------------------------------------------------------------
RESIDENTIAL                                     4 days*
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Business lines/trunks; plant or other           AS NEGOTIATED
facilities not available and must be
provisioned
--------------------------------------------------------------------------------
ESSX(R)Multi Serv (Centrex)(sm)
--------------------------------------------------------------------------------
New/To & From                                   AS NEGOTIATED
--------------------------------------------------------------------------------
Add/Changes (in common block)
          1-3 lines                             2 business days
--------------------------------------------------------------------------------
          4-9 lines                             3 business days
--------------------------------------------------------------------------------
          Over 24 lines                         5 business days
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
UNBUNDLED NETWORK ELEMENTS
--------------------------------------------------------------------------------
BUSINESS OR RESIDENTIAL                         The Parties agree to establish
                                                appropriate intervals for
                                                provisioning unbundled Network
                                                Elements by July 1, 1987
--------------------------------------------------------------------------------
FEATURE CHANGES
--------------------------------------------------------------------------------
Orders received before 3:00 p.m.                Completed on day or report.
--------------------------------------------------------------------------------
Orders received after 3:00 p.m.                 Completed before 5:00 p.m.
                                                next business day
--------------------------------------------------------------------------------
SERVICE DISCONNECTS
--------------------------------------------------------------------------------
With no premises visits
--------------------------------------------------------------------------------
BUSINESS OR RESIDENTIAL                         Within 24 hours after receipt of
--------------------------------------------------------------------------------

                                                           Attachment VIII -- 25
<PAGE>

           MCimetro - BellSouth Mississippi Interconnection Agreement

--------------------------------------------------------------------------------
                                                Service Order
--------------------------------------------------------------------------------

*Under normal business conditions

                  2.5.2 Committed Due Date Met:

                  Measures as a percent the actual date service provisioned
                  compared to the date service was scheduled to be provisioned.

                  Measurement:

                           N = Total Appointments Met
                               ----------------------
                           D = Total Appointments Set

                  2.5.3 No Trouble Reported within 30 Days of Order Completion:

                  Measures reliability of service provided to MCIm customers in
                  first 30 days of service.

                  Measurement:


                  POTS:             N =      All troubles on service installed
                                             in less than 30 days in a
                                             calendar month
                                             -----------------------------------
                                    D =      Installations in a calendar month

                                    Note: N and D are not the same order base.

                  Specials:         N =     Troubles on service Installed
                                            in less than 30 days
                                    D =     Installations in a calendar month

                                    Note: N and D are in the same order base.

                  2.5.4 Firm Order Confirmation:

                  Measures the timeliness of receiving a validation that the
                  services ordered will be provisioned.

                  Measurement:

                           N = Total Number of FOCs Sent for the
                               segment of each 24 hour period
                               ----------------------------------

                                                           Attachment VIII -- 26
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           D = Total Number of FOCs Sent in a 24 hour period

                  BellSouth agrees to collect and measure data in 4 hour
                  segments through September 1, 1997. At that time, MCIm and
                  BellSouth will review BellSouth' s ability to provide an
                  Electronic FOC in four hours or less.

                  2.5.5 Notice of Reject or Error Status Within 1 Hour of
                  Receipt (Paper/Electronic):

                  Measures the timeliness of receiving notification that a
                  service order is incorrect and needs to be corrected:

                  Measurement:

                           N = Number of Rejects or Error Status Sent in
                               less than 1 hour
                               --------------------------------------------
                           D = Total Number of Rejects or Error Status Sent

                  2.5.6 Service Orders Provisioned As Requested:

                  (BellSouth and MCIm agree to review appropriate information
                  and develop a proposal to provide this measurement no later
                  than August 1, 1997.)

SECTION 3. CONNECTIVITY BILLING AND RECORDING

This Section 3 describes the requirements for BellSouth to bill and record all
charges MCIm incurs for purchasing services under this Agreement.

         3.1 PROCEDURES

                  3.1.1 BellSouth shall comply with various industry, OBF, and
                  other standards referred to throughout this Agreement. To
                  satisfy these requirements, both parties shall adhere to
                  mutually agreed upon interpretations of all standards referred
                  to in this Agreement.

                  3.1.2 BellSouth shall record and bill in accordance with this
                  Agreement those charges MCIm incurs as a result of MCIm
                  purchasing from BellSouth services, as set forth in this
                  Agreement (hereinafter "Connectivity Charges").

                                                           Attachment VIII -- 27
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  3.1.3.BellSouth will bill charges for interconnection and
                  resale (within 180 days of the execution of this agreement) in
                  a CABS format. BellSouth will conform each CABS bill in
                  accordance with CABS guidelines.

                  3.1.4 Each service purchased by MCIm shall be assigned a
                  separate and unique billing code in the form agreed to by the
                  parties and such code shall be provided to MCIm on each
                  Connectivity Bill in which charges for such services appear.

                        3.1.4.1 Each such billing code shall enable MCIm to
                        identify the service as ordered by MCIm.

                  3.1.5 Each Connectivity Bill shall set forth the quantity and
                  description of each such service provided and billed to MCIm.
                  All Connectivity Charges billed to MCIm shall indicate the
                  state from which such charges were incurred.

                  3.1.6 BellSouth shall bill MCIm for each service supplied by
                  BellSouth to MCIm pursuant to this Agreement at the rates
                  forth in this Agreement.

                  3.1.7 BellSouth shall bill MCIm for the Connectivity Charges
                  incurred; provided that, for those usage based Connectivity
                  Charges where actual charge information is not determinable by
                  BellSouth because the jurisdiction (i.e., interstate,
                  interstate/interLATA, intrastate, intrastate/ intraLATA,
                  local) of the traffic is unidentifiable, or for other reason,
                  the parties shall jointly develop a process to determine the
                  appropriate charges.

                  3.1.8 Measurement of usage-based Connectivity Charges shall be
                  in actual conversation seconds. The total conversation seconds
                  per chargeable traffic types shall be totaled for the entire
                  monthly bill cycle and then rounded to the next whole minute.
                  State tariffs apply for resold usage plans.

                  3.1.9 BellSouth shall provide to MCIm at no additional charge
                  a Single Point of Contact through a Local Carrier Service
                  Center (LCSC), or similar function, for handling any
                  Connectivity Billing questions or problems that may arise
                  during the implementation and performance of the terms and
                  conditions of this Agreement.

                  3.1.10 BellSouth shall provide single point of contact for
                  handling of any data exchange questions or problems that may
                  arise during the implementation and performance of the terms
                  and conditions of this Agreement.

                                                           Attachment VIII -- 28
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  3.1.11 As soon as possible after completion of this Agreement,
                  each party shall provide the other party written notice of
                  which form of the monthly Connectivity Bill is to be deemed
                  the official bill to assist the parties in resolving any
                  conflicts that may arise between the official bill and another
                  form of bill received via a different media which purportedly
                  contain the same charges as are on the official bill.

                  3.1.12 If either party requests an additional copy(ies) of a
                  bill, such party shall pay the other party a reasonable fee
                  per additional bill copy, unless such copy was requested due
                  to errors, omissions, or corrections or the failure of the
                  transmission to comply with the specifications set forth in
                  this Agreement.

                  3.1.13 When sending Connectivity Bills via electronic
                  transmission, to avoid transmission failures or the receipt of
                  Connectivity Billing information that cannot be processed,
                  MCIm shall provide BellSouth process specifications. Both
                  parties shall comply with processing specifications when
                  transmitting Connectivity Billing data to each other. Both
                  parties shall provide notice to the other party if a
                  Connectivity Billing transmission is received that does not
                  meet specifications or that such party cannot process. Such
                  transmission shall be corrected and resubmitted to the other
                  party, at the resubmitting party's sole expense, in a form
                  that can be processed. The payment due date for such
                  resubmitted transmissions shall be thirty (30) days from the
                  issue date of the bill in a form that can be processed and
                  that meets the specifications set forth in this Attachment.

                  3.1.14 BellSouth shall deliver to a location specified by
                  MCIm, billing information via Network Data Mover (NDM),
                  magnetic tape or paper, as agreed to by MCIm and BellSouth. In
                  the event of an emergency, system failure or other such
                  condition which prevents BellSouth from transmitting via NDM,
                  BellSouth shall notify MCIm of such difficulties within twenty
                  four (24) hours of detection. BellSouth shall deliver to a
                  location specified by MCIm billing information via magnetic
                  tape or paper, as agreed to by MCIm and BellSouth. The parties
                  acknowledge that all tapes transmitted to the other party via
                  U.S. Mail or Overnight Delivery and which contain Connectivity
                  Billing data shall not be returned to the sending party.

                  3.1.15 Subject to the terms of this Agreement, including
                  without limitation Section 3.1.18 of this Attachment VIII,
                  MCIm shall pay BellSouth within thirty (30) days from the
                  issue date of the bill. If the payment due date is a Saturday,
                  Sunday or has been

                                                           Attachment VIII -- 29
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  designated a bank holiday payment shall be made the next
                  business day.

                  3.1.16 Left Blank Intentionally

                  3.1.17 Left Blank Intentionally

                  3.1.18 Bill Reconciliation

                           3.1.18.1 Each party agrees to notify the other party
                           upon the discovery of a billing discrepancy "Notice
                           of Discrepancy".

                           3.1.18.2 In the event of such Notice of Discrepancy,
                           the parties shall endeavor to resolve the discrepancy
                           within sixty (60) calendar days notification using
                           normal business procedures. If the discrepancy is
                           disputed, resolution of such dispute is expected to
                           occur at the first level of management resulting in a
                           recommendation for settlement of the dispute and
                           closure of a specific billing period.

                           3.1.18.3 Closure of a specific billing period shall
                           occur by joint Agreement of the parties whereby the
                           parties agree that such billing period is closed to
                           any further analysis and financial transactions,
                           except those resulting from an Audit. Closure shall
                           take place within nine (9) months of the Bill Date.
                           The month being closed represents those Connectivity
                           Charges that were billed or should have been billed
                           by the respective Bill Date.

                           3.1.18.4 If the dispute is not resolved within the
                           allotted time frame, the following resolution
                           procedure shall begin:

                                    3.1.18.4.1 If the dispute is not resolved
                                    within sixty (60) days of the Notice of
                                    Discrepancy, the dispute shall be escalated
                                    to the second level of management for
                                    resolution.

                                    3.1.18.4.2 If the dispute is not resolved
                                    within ninety (90) days of Notice of
                                    Discrepancy, the dispute shall be escalated
                                    to the third level of management for
                                    resolution.

                                    3.1.18.4.3 If the dispute is not resolved
                                    within one hundred and twenty (120) days of
                                    the Notice of Discrepancy, the dispute may
                                    be resolved pursuant to Section 23 (Dispute
                                    Resolution Procedures) of Part A

                                                           Attachment VIII -- 30
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    of this Agreement.

                                    3.1.18.4 If MCIm disputes Connectivity
                                    Charges and the dispute is resolved in favor
                                    of MCIm, BellSouth shall credit the
                                    Connectivity Bill of MCIm for the amount of
                                    the disputed charges.

                                    3.1.19 BellSouth shall reimburse MCIm for
                                    incorrect Connectivity Billing charges
                                    including without limitation: overcharges,
                                    services ordered or requested but not
                                    delivered, interrupted services, services of
                                    poor quality; and installation problems if
                                    caused by BellSouth. Such reimbursements
                                    shall be set forth in the appropriate
                                    section of the Connectivity Bill pursuant to
                                    CABS, or SECAB standards.

                  3.1.20 Left Blank Intentionally

                  3.1.21 When MCIm collocates with BellSouth in BellSouth's
                  facility as described in this Agreement, capital expenditures
                  (e.g., costs associated with building the "cage"), shall not
                  be included in the Connectivity Bill provided to MCIm pursuant
                  to this Attachment VIII. All such capital expenses shall be
                  given a unique BAN and invoice number. All invoices for
                  capital expenses shall be sent to the location specified by
                  MCIm for payment. All other non-capital recurring collocation
                  expenses shall be billed to MCIm in accordance with this
                  Agreement. (The CABS Billing Output Specifications ("BOS")
                  documents provide the guidelines on how to bill the
                  Connectivity Charges associated with collocation.) The bill
                  label for such collocation charges shall be entitled
                  "Expanded Interconnection Service." The bill label for
                  non-capital recurring collocation expenses shall be entitled
                  "Collocation."

                  3.1.22 LEC shall be responsible for billing and collecting
                  charges from IXCs for access related to interexchange calls
                  generated by resale subscribers.

                  3.1.23 When MCIm owns the end office, BellSouth shall not bill
                  RIC to either MCIm or other IXCs.

                  3.1.24 Left Blank Intentionally

                  3.1.25 BellSouth shall establish a switched access meet point
                  billing arrangement with MCIm. This arrangement will include
                  tandem routed IXC calls and IXC calls routed through a line
                  that is ported via Remote Call Forward (RCF) or FLEX DID from
                  the BellSouth to MCIm.

                                                           Attachment VIII -- 31
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           3.1.25.1 MCIm will bill for carrier common line,
                           local switching, RIC, and its portion of the
                           transport charges for tandem routed IXC calls. For
                           lines that are ported from the BellSouth to MCIm,
                           BellSouth will bill only transport charges. MCIm will
                           bill for all other applicable access charges.

                           3.1.25.2 BellSouth and MCIm will provide all
                           necessary switched access records to each other for
                           access billing.

3.2 INFORMATION EXCHANGE AND INTERFACES

         3.2.1 BellSouth shall provide MCIm monthly Connectivity Bills that
         include all Connectivity Charges incurred by and credits and/or
         adjustments due to MCIm for those services ordered, established,
         utilized, discontinued or performed pursuant to this Agreement.
         BellSouth shall issue multiple bills per month, on the first day of the
         month until otherwise notified by MCIm and the billing cycle shall be
         on a calendar basis. Each Connectivity Bill provided by BellSouth to
         MCIm shall include:

                  3.2.1.1 all non-usage sensitive charges incurred for the
                  period beginning with the day after the current bill date and
                  extending to, and including, the next bill date;

                  3.2.1.2 any known unbilled non-usage sensitive charges for
                  prior periods;

                  3.2.1.3 unbilled usage sensitive charges for the period
                  beginning with the last bill date and extending up to, but not
                  including, the current bill date for interconnection and
                  extending through the bill date for resold services;

                  3.2.1.4 any known unbilled usage sensitive charges for
                  prior periods;

                  3.2.1.5 any known unbilled adjustments.

                  3.2.1.6 Interim Number Portability. MCIm shall become the
                  Customer of Record for the original BellSouth' s telephone
                  number(s). BellSouth shall use its reasonable efforts to
                  provide MCIm with a consolidated billing statement for all
                  collect and billed-to-3rd-number calls associated with those
                  numbers, with sub-account detail by retained number. Such
                  billing statements shall be delivered in the Carrier Access
                  Billing System/Small Exchange Carrier Access Billing

                                                           Attachment VIII -- 32
<PAGE>

                  MCImetro - BellSouth Mississippi Interconnection Agreement

                        System ("CABS/SECABS") format when defined by the
                        Ordering and Billing Forum ("OBF").

                  3.2.2 BellSouth shall make available during normal business
                  days, pursuant to Section 4 of this Attachment, usage call
                  detail information.

                  3.2.3 The Bill Date must be present on each bill transmitted
                  by BellSouth to MCIm, must be a valid calendar date, and not
                  more than one (1) year old. Connectivity Bills shall not be
                  rendered for any Connectivity Charges which are incurred under
                  this Agreement on or before one (1) year preceding the Bill
                  Date, except as otherwise permitted by law.

                  3.2.4 On each bill where "Jurisdiction" is identified, local
                  and local toll charges shall be identified as "Local" and not
                  as interstate, interstate/ interLATA, intrastate, or
                  intrastate/intraLATA. BellSouth shall provide from and through
                  dates for charges rendered on all Connectivity Bills.

                  3.2.5 BellSouth shall separately identify, via USOCs, business
                  charges from residence charges, as appropriate, and shall
                  assign a specific adjustment or reference number provided by
                  MCIm to each adjustment and credit included on the
                  Connectivity Bill.

                  3.2.6 Left Blank Intentionally

                  3.2.7 BellSouth and MCIm shall issue all Connectivity Bills in
                  accordance with the terms and conditions set forth in this
                  Section 3. On Connectivity Bills BellSouth renders to MCIm,
                  BANs shall be 13 character alpha/numeric. The Bill Date shall
                  be the same day month to month. Each party shall provide the
                  other party at least thirty (30) calendar days written notice
                  prior to changing, adding or deleting a BAN. The parties shall
                  provide one Connectivity Billing invoice associated with each
                  BAN. Each invoice must contain an invoice number (which will
                  vary from month to month). On each bill associated with a BAN,
                  the appropriate invoice number and the charges contained on
                  such invoice must be reflected. All Connectivity Bills must be
                  received by the other party no later than ten (10) calendar
                  days from Bill Date and at least twenty (20) calendar days
                  prior to the payment due date (as described in this
                  Attachment), whichever is earlier. Any Connectivity Bill
                  received on a Saturday, Sunday or a day designated as a bank
                  holiday will be deemed received the next business day. If
                  either party fails to receive Connectivity Billing data and
                  information within the time

                                                           Attachment VIII -- 33
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  period specified above the payment due date will be extended
                  by the number of days receipt has been delayed.

                  3.2.8 BellSouth shall make best efforts to issue all
                  Connectivity Bills containing such billing data and
                  information in accordance with the most current version of
                  CABS /SECABS published by Bellcore, or its successor, or such
                  later versions as are adopted by Bellcore, or its successor.
                  To the extent that there are no CABS, or SECAB standards
                  governing the formatting of certain data, such data shall be
                  issued in the format mutually agreed to by BellSouth and MCIm.

                  3.2.9 BellSouth and MCIm agree that each party shall transmit
                  Connectivity Billing information and data in the appropriate
                  CABS or SECAB format electronically via NDM to the other party
                  at the location specified by such party. MCIm data centers
                  will be responsible for originating the calls for data
                  transmission. BellSouth shall transmit in accordance with
                  mutually agreed to technical specifications. MCIm will supply
                  to BellSouth its RACF ID and password before the first
                  transmission of data via NDM. Any changes to either party's
                  NDM Node ID must be sent to the other party no later than
                  thirty (30) calendar days before the changes take effect.

                  3.2.10 In emergency situations when tape transmittal has been
                  used BellSouth shall adhere to the tape packaging requirements
                  set forth in this Agreement. Where magnetic tape shipping
                  containers are transported in freight compartments, adequate
                  magnetic field protection shall be provided by keeping a
                  6-inch distance from any magnetic field generating device
                  (except a magnetron-tape device). BellSouth shall only use
                  those shipping containers that contain internal insulation to
                  prevent damage. BellSouth shall clearly mark on the outside of
                  each shipping container its name, contact and return address.
                  BellSouth shall not ship any Connectivity Billing tapes in
                  tape canisters.

                  3.2.11 All emergency billing data transmitted via tape must be
                  provided on a cartridge (cassette) tape and must be of high
                  quality, conform to the parties' record and label standards,
                  9-track, odd parity, 6250 BPI group coded recording mode and
                  extended binary-coded decimal interchange code ("EBCDIC").
                  Each reel of tape must be 100% tested at 20% or better
                  "clipping" level with full width certification and permanent
                  error free at final inspection. MCIm reserves the right to
                  destroy a tape that has been determined to have unrecoverable
                  errors. MCIm also reserves the right to replace a tape with
                  one of equal or better quality.

                                                           Attachment VIII -- 34
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

         3.2.12 Billing data tapes used in emergency circumstances shall have
         the following record and label standards. The dataset serial number on
         the first header record of an IBM standard tape label also shall have
         the following format.

--------------------------------------------------------------------------------
                            CABS BOS                     SECAB
--------------------------------------------------------------------------------
Record Length               bytes (fixed length)         bytes (fixed length)
--------------------------------------------------------------------------------
Blocking factor             records per block            Not Applicable
--------------------------------------------------------------------------------
Block size                  bytes per block              Not Applicable
--------------------------------------------------------------------------------
Labels                      Standard IBM Operating       Standard IBM Operating
                            System                       System
--------------------------------------------------------------------------------

                  3.2.13 A single 6-digit serial number must appear on the
                  external (flat) surface of the tape for visual identification.
                  This number shall also appear in the "dataset serial number
                  field" of the first header record of the IBM standard tape
                  label. This serial number shall consist of the character "V"
                  followed by the reporting location's four digit Originating
                  Company Code and a numeric character chosen by the sending
                  company. The external and internal label shall be the same.
                  The dataset name shall appear on the flat side of the reel and
                  also in the "data set name field" on the first header record
                  of the IBM standard tape label. BellSouth's name, address,
                  and contact shall appear on the flat side of the cartridge or
                  reel

                  3.2.14 Tape labels shall conform to IBM OSNS Operating System
                  Standards contained in the IBM Standard Labels Manual. IBM
                  standard labels are 80-character records recorded in EBCDIC,
                  odd parity.

                  3.2.15 BellSouth shall conform to the Standard Volume Label
                  Format which will be prescribed by MCIm.

                  3.2.16 BellSouth shall use The IBM Standard Dataset Label
                  Format which will be prescribed by MCIm.

                  3.2.17 BellSouth shall use mutually agreed upon test &
                  production dataset formats.

         3.3 STANDARDS

                                                           Attachment VIII -- 35
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  3.3.1 Within thirty (30) days of the execution of this
                  Agreement, BellSouth shall send to MCIm connectivity bill data
                  in the appropriate mechanized format (i.e. CABS or SECAB) for
                  testing to ensure that bills can be processed and that bills
                  comply with the requirements of this Attachment. After receipt
                  of the test data from BellSouth MCIm will notify BellSouth if
                  the connectivity billing transmission meets MCIm's testing
                  specifications. If the transmission fails to meet MCIm's
                  testing specifications, BellSouth shall make the necessary
                  corrections. At least three (3) sets of testing data must meet
                  MCIm's testing specifications prior to BellSouth sending MCIm
                  a mechanized production connectivity bill for the first time
                  via electronic transmission or tape. Thereafter, BellSouth may
                  begin sending MCIm production connectivity bills via
                  electronic transfer on the next Bill Date, or within ten (10)
                  days, whichever is later.

                  3.3.2 At least thirty (30) days prior to any change in
                  existing formats or change to a different format, BellSouth
                  shall send to MCIm connectivity bill data in the appropriate
                  mechanized format for testing to ensure that the bills can be
                  processed and that the bills comply with the requirements of
                  this Attachment. BellSouth agrees that it shall not send to
                  MCIm bill data in the new mechanized format until such bill
                  data has met the testing specifications as set forth in this
                  subsection.

                  3.3.3 During the testing period, BellSouth shall transmit to
                  MCIm Connectivity Billing data and information via paper or
                  tape as specified by MCIm. Test tapes shall be sent to a MCIm
                  specified location.

                  3.3.4 BellSouth agrees that if it transmits data to MCIm in a
                  mechanized format, BellSouth shall also comply with the
                  following specifications which are not contained in CABS or
                  SECAB guidelines but which are necessary for MCIm to process
                  Connectivity Billing information and data:

                  3.3.5 The Bill Date shall not contain spaces or non-numeric
                  values.

                           3.3.5.1 Each Connectivity Bill must contain at least
                           one detail record.

                           3.3.5.2 Any "From" Date should be less than the
                           associated "Thru" Date and neither date can contain
                           spaces.

                                                           Attachment VIII -- 36
<PAGE>

           MCimetro - BellSouth Mississippi Interconnection Agreement

                           3.3.5.3 The Invoice Number must not have embedded
                           spaces or low values.

                  3.3.6 LEFT BLANK INTENTIONALLY

                  3.3.7 LEFT BLANK INTENTIONALLY

         3.4 PERFORMANCE MEASUREMENTS & REPORTING

                  3.4.1 Left Blank Intentionally

Section 4. Provision Of Subscriber Usage Data

This Section 4 sets forth the terms and conditions for BellSouth's provision of
Recorded Usage Data (as defined in this Attachment VIII) to MCIm and for
information exchange regarding long distance billing.

         4.1 PROCEDURES

                  4.1.1 General

                  4.1.1.1 BellSouth shall comply with BellSouth EMR industry
                  standards in delivering customer usage data to MCIm.

                  4.1.1.2 BellSouth shall provide MCIm with Recorded Usage Data
                  in accordance with provisions of Section 4 of this document.

                  4.1.1.3 BellSouth shall provide MCIm with copies of detail
                  usage on MCIm accounts. However, following execution of this
                  Agreement, MCI, may submit and BellSouth will accept a PON for
                  a time and cost estimate for development by BellSouth of the
                  capability to provide copies of other detail usage records for
                  completed calls originating from lines purchased by MCIm for
                  resale. Recorded Usage Data includes, but is not limited to,
                  the following categories of information:

                           Completed Calls

                           Use of CLASS/LASS/Custom Features (under
                           circumstances where BellSouth records activations
                           for its own end user billing).
                           Calls To Information Providers Reached Via
                           BellSouth Facilities And Contracted By BellSouth
                           Calls To Directory Assistance Where BellSouth

                                                           Attachment VIII -- 37
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           Provides Such Service To An MCIm Subscriber Calls
                           Completed Via BellSouth-Provided Operator Services
                           Where BellSouth Provides Such Service To MCIm's
                           Local Service Subscriber and usage is billable to an
                           MCIm account. For BellSouth-Provided MULTISERV
                           Service, Station Level Detail Records Shall Include
                           Complete Call Detail And Complete Timing Information
                           where Technically Feasible.

                  4.1.1.4 Retention of Records: BellSouth shall maintain a
                  machine readable back-up copy of the message detail provided
                  to MCIm for a minimum of forty-five (45) calendar days.
                  BellSouth shall provide any data back-up to MCIm upon the
                  request of MCIm within the record retention interval and at
                  the rates set forth in Attachment I.

                  4.1.1.5 BellSouth shall provide to MCIm Recorded Usage Data
                  for MCIm subscribers. BellSouth shall not submit other carrier
                  local usage data as part of the MCIm Recorded Usage Data.

                  4.1.1.6 BellSouth shall bill to MCIm any recurring or
                  non-recurring charges appropriate based on the Local Service
                  Requests submitted to the BellSouth by MCIm. BellSouth

                  4.1.1.7 Left Blank Intentionally

                  4.1.1.8 BellSouth shall provide Recorded Usage Data to MCIm
                  billing locations as designated by MCIm, segregated no lower
                  than NXX level.

                  4.1.1.9 BellSouth shall establish a Local Carrier Service
                  Center (LCSC) or similar function to serve as MCIm's single
                  point of contact to respond to MCIm call usage, data error,
                  and record transmission inquiries.

                  4.1.1.10 BellSouth shall provide MCIm with a single point of
                  contact, Remote Identifiers (IDs), and assistance in resolving
                  usage data volume fluctuations for each sending location.

                  4.1.1.11 MCIm shall provide a single point of contact
                  responsible for receiving usage transmitted by BellSouth and
                  receiving usage tapes from a courier service in the event of a
                  facility outage.

                                                           Attachment VIII -- 38
<PAGE>

                  MCImetro - BellSouth Mississippi Interconnection Agreement

                  4.1.1.12 BellSouth shall bill and MCIm shall pay the charges
                  for Recorded Usage Data. Billing and payment shall be in
                  accordance with the applicable terms and conditions set forth
                  in this Agreement.

                  4.1.1.13 Without waiver of, and in addition to the Audit and
                  Examination rights in the Section 22 (Audits and Examinations
                  of Part A) of this Agreement, upon reasonable notice and at
                  reasonable times MCIm or its authorized representatives may
                  examine BellSouth's documents, systems, records and
                  procedures which relate to the recording and transmission of
                  the Usage data to MCIm under this Attachment.

         4.1.2    Charges

                  4.1.2.1 BellSouth shall charge fees as delineated in
                  Attachment I.

                  4.1.2.2 No charges shall be assessed for incomplete call
                  attempts, nor will attempts be delivered to MCIm for calls
                  which originate from lines purchased by MCIm for resale.

         4.1.3    Central Clearinghouse & Settlement

                  4.1.3.1 In connection with CMDS hosting functions, BellSouth
                  shall comply with Clearinghouse and Incollect/Outcollect
                  procedures in accordance with CMDS standards.

                  4.1.3.2 BellSouth shall settle with MCIm for both intra-region
                  and inter-region billing exchanges of calling card, bill-to-
                  third party, and collect calls in accordance with the
                  prevailing CMDS standards.

         4.1.4    Lost Data

                  4.1.4.1 Loss of Recorded Usage Data - In the event MCIm
                  Recorded Usage Data is determined to have been lost, damaged
                  or destroyed as a result of an error or omission by BellSouth
                  in its performance of the recording function, upon MCIm's
                  request, BellSouth shall attempt to recover the Recorded Usage
                  Data at no charge to MCIm. In the event

                                                           Attachment VIII -- 39
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  the data cannot be recovered by BellSouth, BellSouth and MCIm
                  shall mutually agree upon a credit amount based upon an
                  estimate of the affected messages and associated revenue,
                  reduced by a mutually agreed upon estimate of associated
                  Recording Service charges, based upon the method described
                  below. This method shall be applied on a consistent basis,
                  subject to modifications agreed to by BellSouth and MCIm. This
                  estimate shall be used to adjust amounts MCIm owes BellSouth
                  for services BellSouth provides in conjunction with the
                  provision of Recorded Usage Data, and BellSouth's liability
                  for lost, damaged or destroyed Recorded Usage Data shall be
                  limited to the application of the credit described in this
                  section.

                  4.1.4.2 The lost revenue per day will be based upon the daily
                  average of revenues for the corresponding days of the week
                  (e.g. four Mondays) in the most recent month for which MCIm
                  supplied data to BellSouth before the day of loss, except:

                           4.1.4.2.1 If the loss occurs on a weekday which is a
                           holiday (except Mother's Day or Christmas),
                           BellSouth will use the daily average of revenues from
                           the four Sundays of the most recent month for which
                           MCIm supplied data to BellSouth before the day of
                           loss;

                           4.1.4.2.2 If the loss occurs on Mother's Day or
                           Christmas, BellSouth will use the daily average of
                           revenue from that day in the preceding year (if
                           available from the data supplied by MCIm to BellSouth
                           before the day of loss); and

                           4.1.4.2.3 If the loss occurs on a day not a holiday
                           but one (or more) of the days lost is a holiday,
                           BellSouth will use additional corresponding days from
                           the next most recent month for which MCIm supplied
                           data to BellSouth before the day of loss.

           4.1.5 Testing, Changes and Controls

                  4.1.5.1 The Recorded Usage Data, EMR format, content, and
                  transmission process shall be tested in a manner mutually
                  agreed upon by BellSouth and MCIm.

                                                           Attachment VIII -- 40
<PAGE>

           MCimetro - BellSouth Mississippi Interconnection Agreement

                  4.1.5.2 Interface Testing: The purpose of this test is to
                  ensure that the usage records can be sent by BellSouth to MCIm
                  and can be accepted and processed by MCIm. BellSouth shall
                  provide a test file to MCIm's designated Regional Processing
                  Center (RPC) in the format that shall be used for live
                  day-to-day processing. The file shall contain that production
                  data which MCIm and BellSouth agree upon. MCIm shall review
                  the file and verify that it conforms to agreed upon EMR
                  standards. MCIm shall notify BellSouth in writing whether the
                  format is acceptable. MCIm shall also provide BellSouth with
                  the agreed-upon control reports as part of this test.

                  4.1.5.3 Operational Test: The purpose of this test is to
                  ensure that volumes of usage in consecutive sequence can
                  be extracted. distributed, and processed by BellSouth and
                  MCIm.

                  4.1.5.4 For testing purposes BellSouth shall provide MCIm with
                  BellSouth recorded, unrated usage for a minimum of five (5)
                  consecutive days. MCIm shall provide BellSouth with the
                  message validation reports associated with test usage.

                  4.1.5.5 Test File: Test data should be transported via NDM
                  whenever possible. In the event that courier service must be
                  used to transport test media, the physical tape
                  characteristics to be used are described in this Agreement.

                  4.1.5.6 Periodic Review: Control procedures for all usage
                  transferred between BellSouth and MCIm shall require periodic
                  review. This review may be included as part of an annual audit
                  of BellSouth by MCIm or as part of the normal production
                  interface management function. Breakdowns which impact the
                  flow of usage between BellSouth and MCIm must be identified
                  and jointly resolved as they occur. The resolution may include
                  changes to control procedures, as similar problems would be
                  avoided in the future. Any changes to control procedures would
                  need to be mutually agreed upon by MCIm and BellSouth.

                  4.1.5.7 BellSouth Software Changes:

                           4.1.5.7.1 When BellSouth plans to introduce any
                           software changes which impact the format or content
                           structure of the usage data feed to MCIm, designated

                                                           Attachment VIII -- 41
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  BellSouth personnel shall notify MCIm no less than one hundred
                  twenty (120) calendar days before such changes are
                  implemented.

                  4.1.5.7.2 BellSouth shall communicate the projected changes to
                  the single point of contact in MCIm so that potential impacts
                  on MCIm processing can be determined.

                  4.1.5.7.3 MCIm personnel shall review the impact of the change
                  on the entire control structure and the Post Conversion Test
                  Plan, herein. MCIm shall negotiate any perceived problems with
                  BellSouth and shall arrange to have the data tested utilizing
                  the modified software.

                  4.1.5.7.4 If it is necessary for BellSouth to request changes
                  in the schedule, content or format of usage data transmitted
                  to MCIm, BellSouth shall notify MCIm. BellSouth and MCIm agree
                  to comply with changes in EMR standard as they from time to
                  time occur.

          4.1.5.8 MCIm Requested Changes:

                  4.1.5.8.1 MCIm may request changes in the schedule, content,
                  format of the usage data transmitted from BellSouth, as deemed
                  necessary by MCIm within the constraints of EMR industry
                  standard requirements.

                  4.1.5.8.2 When the negotiated changes are to be implemented,
                  MCIm and/or BellSouth shall arrange for testing of the
                  modified data in a mutually agreed Post Conversion Test Plan
                  designed to encompass all types of changes to the usage data
                  transferred by BellSouth to MCIm and the methods of
                  transmission for that data.

          4.1.5.9 BellSouth System Change Description:

                  4.1.5.9.1 For a BellSouth change to the Recorded Usage Data ,
                  BellSouth shall provide MCIm with an overall description of
                  the change, stating the objective and a brief explanation of
                  the reasons for

                                                           Attachment VIII -- 42
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  the change.

                  4.1.5.9.2 During the initial negotiations regarding the
                  change, BellSouth shall provide a list of the specific records
                  and/or systems impacted by the change to designated MCIm
                  personnel.

                  4.1.5.9.3 BellSouth shall also provide MCIm a detailed
                  description of the changes to be implemented. It shall include
                  sufficient detail for designated MCIm personnel to analyze and
                  estimate the effects of the changes and to design tests to
                  verify the accuracy of the implementation.

         4.1.5.10 Change Negotiations:

                  4.1.5.10.1 MCIm shall be notified in writing of all proposed
                  negotiations initiated by BellSouth. In turn, MCIm shall
                  notify BellSouth in writing of proposed change negotiations
                  initiated by MCIm. These written notifications will be
                  directed to the single point of contact for the respective
                  companies.

                  4.1.5.10.2. After formal notification of planned changes,
                  whether originated by BellSouth or MCIm, designated MCIm
                  personnel shall schedule negotiation meetings as required with
                  designated BellSouth personnel. The first meeting should
                  produce the overall change description (if not previously
                  furnished) and the list of records and/or systems affected.

                  4.1.5.10.3 In subsequent meetings, BellSouth shall provide the
                  detailed description of changes to be implemented. After
                  reviewing the described changes, designated MCIm personnel
                  shall negotiate a detailed test procedure with BellSouth.

         4.1.5.11 Changes to controls:
         MCIm may request changes to the control structure. BellSouth Requested
         control changes will be negotiated.

         4.1.5.12 Verification Of Changes

                  4.1.5.12.1 Based on the detailed description of

                                                           Attachment VIII -- 43
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  changes furnished by BellSouth, MCIm and BellSouth
                  personnel shall:

                           Determine the type of change(s) to be implemented.
                           Develop a comprehensive test plan. Negotiate
                           scheduling and transfer of modified data with
                           BellSouth. Confirm that test data is verified and
                           acceptable by both BellSouth and MCIm.

         4.1.5.13 Introduction of Changes:

                  4.1.5.13.1 When all the testing requirements have been met and
                  the results reviewed and accepted, designated MCIm and
                  BellSouth personnel shall:

                           Negotiate an implementation schedule. Verify the
                           existence of a contingency plan with the appropriate
                           MCIm personnel. Arrange for the follow-up review of
                           changes with appropriate MCIm personnel. Arrange for
                           appropriate changes in control program, if
                           applicable.

4.2 INFORMATION EXCHANGE AND INTERFACES

         4.2.1 Core Billing Information

                  4.2.1.1 Recorded Usage Data all intraLATA toll and local
                  usage. BellSouth shall provide MCIm with unrated EMR records
                  associated with all billable intraLATA toll and local usage
                  which they record on lines purchased by MCIm for resale. Any
                  billable Category, Group and/or Record types approved in the
                  future for BellSouth shall be included if they fall within the
                  definition of local service resale. MCIm shall be given
                  notification thirty (30) days prior to implementation of a new
                  type, category and / or record.

                  4.2.1.2 BellSouth shall provide rated EMR records only when
                  explicit consent for sending such records has been obtained
                  from MCIm. The following records shall be rated by BellSouth:

                                                           Attachment VIII -- 44
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

         Category 01       Operator handled, person to person, collect
                           calls, bill to third number, SSP record query
         Category 03       Credit & adjustments
         Category 41       Subscriber credit

                  4.2.1.3 All messages billable to an MCIm account will
                  BellSouth be transmitted to MCIm. BellSouth recorded usage
                  billable to MCIm Subscribers.

                  4.2.1.4 Data Delivery Schedules: Data shall be delivered to
                  MCIm by BellSouth daily (Monday through Friday) unless
                  otherwise negotiated. MCIm and/or BellSouth Data Center
                  holidays are excluded. BellSouth and MCIm shall exchange
                  schedules of designated Data Center holidays.

         4.2.2    Supporting Billing Information

                  4.2.2.1 Returned Long Distance Messages and Invoices

                           4.2.2.1.1 EC shall return message records or invoices
                           to MCI for messages or invoices which cannot be
                           billed to a BellSouth end user because BellSouth no
                           longer serves the end user for the associated
                           messages or invoices as a result of the end user
                           telephone number being served by another LEC/CLEC.
                           BellSouth will return IC messages as misdirected if
                           BellSouth no longer serves the end user.

                           4.2.2.1.2 Message records or invoices shall be
                           returned as part of the established unbillable
                           process. Returned messages or invoices shall be in
                           industry-standard EMR format using the OBF-agreed
                           return code 50, unless otherwise negotiated with MCI.

                  4.2.2.1.3 Additional return codes to be used for
                  return designations are as follows:

                           81 - Rated record is received and indicator 19 is set
                           to a value of other than 1 or 3 for a CIC of zeroes.
                           82 - Message is determined to be interLATA, and
                           interLATA is not determined to be applicable.
                           83 - field is designated as numeric field contains
                           non-numeric values.

                                                           Attachment VIII -- 45
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           84 - message is terminating to number that has a
                           NPA 900

                  4.2.2.1.4 The above message and/or invoice returns shall
                  contain the Operating Company Number (OCN), or another
                  identifying number or code as may become a future industry
                  standard, of the LEC serving the end user through resale or
                  portability at the time the invoice or message is returned.

                  4.2.2.1.5 Following are the record types and positions where
                  the OCN should be populated. The error or return code should
                  continue to appear in the standard position.

                  01-XX-XX record:                      positions 168-171
                  01-51-21 record:                      positions 125-128
                  01-51-24 record:                      positions 187-190
                  41-XX-XX record (detail):             positions
                  168-171
                  41-50-XX record (summary):            positions 154-157
                  42-50-XX record (summary):            positions 154-157

                  4.2.2.2 Interim Number Portability. BellSouth shall provide
                  MCIm call detail records identifying each IXC which are
                  sufficient to allow MCIm to render bills to IXCs for calls
                  IXCs place to ported numbers in the BellSouth network which
                  the BellSouth forwards to MCIm for termination.

                  MCIm shall become the Customer of Record for the original
                  BellSouth's telephone number(s), subject to the CALNP
                  arrangements. BellSouth shall provide to MCIm the Electronic
                  Message Records ("EMR") for all calls in a daily electronic
                  Network Data Mover ("NDM") feed or magnetic tape, as specified
                  by MCIm, for MCIm customers.

         4.2.3    Product/Service Specific

                  4.2.3.2 BellSouth shall provide a Specialized Service /
                  Service Provider Charge record to support the Special Features
                  Star Services if these features are part of BellSouth's
                  offering.

         4.2.4    Emergency Information

                                                           Attachment VIII -- 46
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  4.2.4.2 MCIm shall arrange transport facilities per BellSouth
                  tariffed services. BellSouth shall transmit via NDM whenever
                  possible. In the event usage transfer cannot be accommodated
                  by NDM because of extended (one (1) business day or longer)
                  facility outages, BellSouth shall contract for a courier
                  service to transport the data via tape. The data tape will be
                  transported via courier service and costs for delivery will be
                  borne by the company responsible for the outage.

                  4.2.4.3 BellSouth shall comply with the following standards
                  when emergency data is transported to MCI on tape or cartridge
                  via a courier. The data shall be in fixed or variable block
                  format as specified by MCI and:

                  Tape: 9-track, 6250 (or 1600) BPI (Bytes per inch)
                  Cartridge: 38,000 BPI (Bytes per inch)
                  LRECL: 2,472 Bytes
                  Parity: Odd
                  Character Set: Extended Binary Coded Decimal
                  Interchange Code (EBCDIC)
                  External labels: Exchange Carrier Name, Dataset Name (DSN) and
                  volume serial number Internal labels: IBM Industry OS labels
                  shall be used. They consist of a single volume label and two
                  sets of header and trailer labels.

         4.2.5    Rejected Recorded Usage Data

                  4.2.5.1 If MCIm should encounter significant volumes of
                  errored messages that prevent processing by MCIm within its
                  systems, BellSouth will work with MCIm to jointly determine
                  the source and appropriate error resolution. 4.2.5.2 BellSouth
                  must return EMR/EMI records to IXCs with the OBF standard
                  message reject code which indicates that BellSouth no longer
                  serves the end user and which includes the OCN/Local Service
                  Provider ID of the new LEC/Reseller serving the end user.
                  4.2.5.3 Rejected messages or invoices shall be returned to
                  MCIm in accordance with procedures and timeframes already
                  established between BellSouth and MCIm.

         4.2.6    Interfaces

                                                           Attachment VIII -- 47
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  4.2.6.1 BellSouth shall transmit formatted Recorded Usage Data
                  to MCIm via NDM as designated by MCIm.

                  4.2.6.2 MCIm shall notify BellSouth of resend requirements if
                  a pack or entire dataset must be replaced due to pack
                  rejection, damage in transit, dataset name failure, etc.
                  4.2.6.3 Critical edit failure on the Pack Header or Pack
                  Trailer records shall result in pack rejection (e.g., detail
                  record count not equal to grand total included in the pack
                  trailer). Notification of pack rejection shall be made by MCIm
                  within one (1) business day of processing. Rejected packs
                  shall be corrected by BellSouth and retransmitted to MCIm
                  within twenty-four (24) hours or within an alternate timeframe
                  negotiated on a case by case basis. 4.2.6.4 A pack shall
                  contain a minimum of one message record or a maximum of 9,999
                  message records plus a pack header record and a pack trailer
                  record. A file transmission contains a maximum of 99 packs. A
                  dataset shall contain a minimum of one pack. BellSouth shall
                  provide MCIm one dataset per sending location, with the agreed
                  upon RAO/OCN populated in the Header and Trailer records.

         4.2.7    Formats & Characteristics

                  4.2.7.1 Rated in collect messages should be transmitted via
                  the NDM and can be intermingled with the unrated messages. No
                  special packing is needed 4.2.7.2 EMR: BellSouth shall provide
                  Recorded Usage Data in the EMR format and by category, group
                  and record type, and shall be transmitted, via a direct feed,
                  to MCIm. The following is a list of EMR records that MCIm can
                  expect to receive from BellSouth:

                  HEADER RECORD 20-20-01
                  TRAILER RECORD 20-20-02
                  DETAIL RECORDS * 01-01-01, 06, 07, 08, 09, 16, 18, 31, 32, 33,
                  35, 37, 80, 81, 82, 83
                                      10-01-01, 06, 07, 08, 09, 16, 18, 31,
                  32, 35, 37, 80, 81, 82, 83
                  CREDIT RECORDS 03-01-01, 06, 08, 09, 14, 17, 18, 31, 32, 35,
                  37, 80, 81, 82,

                                                           Attachment VIII -- 48
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  RATED CREDITS 41-01-01, 06, 08, 09, 14, 17, 18, 31, 32, 35,
                  37, 80, 81, 82,
                  CANCEL RECORDS 51-01-01, 06, 08, 09, 14, 17, 18, 31, 32, 35,
                  37, 80, 81, 82, (58 -01 -xx where the record being canceled is
                  unrated)
                  CORRECTION RECORDS 71-01-01, 06, 08, 09, 14, 17, 18, 31, 32,
                  35, 37, 80, 81, 82,

                  * Category 01 is utilized for Rated Messages; Category 10 is
                  utilized for Unrated Messages. Category 10 records are to have
                  indicator 13 populated with a value of 5

                  In addition, BellSouth shall provide a 42-50-01 Miscellaneous
                  Charge record to support the Special Features Star Services if
                  these features are part of BellSouth's offering.

                  4.2.7.3 BellSouth shall comply with the most current version
                  of Bellcore standard practice guidelines for formatting EMR
                  records.

                  4.2.7.4 The Interfacing Bell RAO, OCN, and Remote Identifiers
                  shall be used by MCIm to control invoice sequencing and each
                  shall have its own invoice controls.

                  4.2.7.5 The file's Record Format (RECFM) shall be Variable
                  Block with 175 character EMR record, plus modules if
                  appropriate.

                  4.2.7.6 Initially, BellSouth may elect not to comply with
                  specific sorting requirements. However, MCIm may elect to
                  require BellSouth to sort PACKS in accordance with MCIm
                  specifications at a later date.

                  4.2.7.7 BellSouth shall transmit the usage to MCIm using
                  dataset naming conventions prescribed by MCIm.

         4.2.8    Controls

                  4.2.8.1 MCIm shall test and certify the NDM interface to
                  ensure the accurate receipt of Recorded Usage Data.

                  4.2.8.2 Header and trailer records shall be populated in
                  positions 13-27 with the following information:

                                                           Attachment VIII -- 49
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                            13-14               Invoice numbers (1-99)
                            15-16               Bell Co. ID number
                            17-19               Interfacing Bell RAO Code
                            20-23               MCIm OCN - value 7229
                            24-27               Reseller OCN

                  The trailer grand total record count shall be populated with
                  total records in pack (excluding header & trailer)

                  4.2.8.3 Control Reports: MCIm accepts input data provided by
                  BellSouth in EMR format in accordance with-the requirements
                  and specifications detailed in this Section 8 of the
                  Attachment III. In order to ensure the overall integrity of
                  the usage being transmitted from BellSouth to MCIm, data
                  transfer control reports shall be required. These reports
                  shall be provided by MCIm to BellSouth on a daily or otherwise
                  negotiated basis and reflect the results of the processing for
                  each pack transmitted by BellSouth.

                  4.2.8.4 Control Reports - Distribution: Since BellSouth is
                  not receiving control reports, dataset names shall be
                  established during detailed negotiations.

                  4.2.8.5 Message Validation Reports: MCIm shall provide the
                  following once(1) per day (or as otherwise negotiated) Message
                  Validation reports to the designated BellSouth System Control
                  Coordinator. These reports shall be provided for all data
                  received within BellSouth Local Resale Feed and shall be
                  transmitted Monday through Friday.

                  4.2.8.6 Incollect Pack Processing: This report provides vital
                  statistics and control totals for packs rejected and accepted
                  and dropped messages. The information is provided in the
                  following report formats and control levels:

                           BellSouth Name
                           Reseller Total Messages processed in a pack Packs
                           processed shall reflect the number of messages
                           initially erred and accepted within a pack Reseller
                           Total Packs processed

                  4.2.8.7 MCIm requires information on a subscriber's
                  selection of billing method, special language billing, and

                                                           Attachment VIII -- 50
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           other billing options.

         4.3 STANDARDS

                  4.3.1 When requested by MCIm for security purposes, BellSouth
                  shall provide MCIm with Recorded Usage Data as soon as
                  practical. If not available in EMR format, the Recorded Usage
                  Data may be provided in AMA format.

                  4.3.2 BellSouth shall include the Working Telephone Number
                  (WTN) of the call originator on each EMR call record where
                  Technically Feasible.

                  4.3.3 End user subscriber usage records and station level
                  detail records shall be in packs in accordance with EMR
                  standards.

                  4.3.4 BellSouth shall provide Recorded Usage Data to MCIm on a
                  schedule to be determined by the parties once a day Monday
                  through Friday except holidays.

                  4.3.5 BellSouth shall segregate and organize the Recorded
                  Usage Data in a manner mutually agreed upon between BellSouth
                  and MCIm.

         4.4 PERFORMANCE MEASUREMENTS

         4.4.1 ACCOUNT MAINTENANCE

                  4.4.1.1 When notified by a CLEC that a MCIm Customer has
                  switched to CLEC service, BellSouth shall provision the
                  change, and notify MCIm via CONNECT:Direct that the customer
                  has changed to another service provider ("OUTPLOC") within one
                  (1) business day:

                  Measurement:

                             N  =  Number of Local Services Changes from MCIm
                                    to Another CLEC Provisioned with
                                    Notification to MCIm in One Business Day
                                   ---------------------------------------------
                             D  =  Total Number of Local Service Changes from
                                    MCIm to Another CLEC Provisioned with
                                    Notification to MCIm.

         4.4.1.2 When notified by MCIm that a customer has

                                                           Attachment VIII -- 51
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  changed his/her PIC only from one interexchange carrier to
                  another carrier, BellSouth shall provision the PIC only change
                  and convey the confirmation of the PIC change via the work
                  order completion feed within one (1) business day.

                  Measurement:

                              N =   Number of PIC Only Changes from One LEC to
                                    Another Initiated by MCIm Provisioned with
                                    Notification via the Work Order Completion
                                    Feed in less than or equal to One Business
                                    Day

                              D =   Total Number of PIC Only Changes from One
                                    LEC to Another initiated by MCIm Provisioned
                                    with Notification via the Work Order
                                    Completion Feed

                  4.4.1.3 If notified by an interexchange carrier using an/01/
                  PIC order record that an MCIm Customer has changed his/her PIC
                  only, BellSouth will reject the order and notify that
                  interexchange carrier a CARE PIC record should be sent to the
                  serving CLEC for processing within one (1) business day of
                  BellSouth's receipt of the PIC order from the IXC.

         Measurement:

                      N =  Number of PIC Change Requests for a MCIm Local
                           Customer Rejected by BellSouth to IXC (pound) One
                           Business Day
                           -----------------------------------------------------
                      D =  Total Number of PIC Changes for a MCIm Local
                           Customer Rejected by BellSouth to IXC

         4.4.2 Timeliness

         BellSouth will mechanically transmit, via CONNECT:Direct, all usage
         records to MCIm's Message Processing Center once daily.

         Measurement:

                      N =  Total Number of Messages Sent within six (6) calendar
                           days from initial Recording
                           -----------------------------------------------------
                      D =  Total Number of Messages Sent

                                                           Attachment VIII -- 52
<PAGE>

                  MCImetro - BellSouth Mississippi Interconnection Agreement

         Target:     greater than or equal to 95% of all messages will be
                     delivered within 6 calendar days from initial
                     recording

         4.4.3 Completeness

         BellSouth will provide all required Recorded Usage Data and ensure that
         it is processed and transmitted within thirty (30) days of the message
         create date.

         Measurement:

                        N  =   Total number of Recorded Usage Data records
                               delivered during the current month that are
                               within thirty (30) days of the message create
                               date.
                               ------------------------------------------- x 100
                        D  =   Total number of Recorded Usage Data Records
                               delivered during the current month.

         Target:            greater than or equal to 98% of all records
                            delivered within 30 days of the message creation

         4.4.4 Recorded Usage Data Accuracy

                  4.4.4.1 Format and Content

                  BellSouth will provide Recorded Usage Data in the format and
                  with the content as defined in the current BellCore EMR
                  document.

                  Measurement:

                       N = Total Number of Recorded Usage Data
                           Transmitted Correctly
                           ---------------------------------------- x 100
                       D = Total Number of Recorded Usage Data
                           Transmitted

                  Target:  greater than or equal to 98% of all recorded
                           records delivered will be
                                                           Attachment VIII -- 53
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                              transmitted correctly

                  4.4.4.2 Transmission

                  BellSouth will ensure that the Recorded Usage Data is
                  transmitted to MCIm error free. The level of detail includes,
                  but is not limited to: detail required to Rating the call,
                  Duration of the call, and Correct Originating/Terminating
                  information pertaining to the call. The error is reported to
                  BellSouth as a Modification Request (MR). The type of MR that
                  corresponds with each MR response time classification shall be
                  mutually determined. Performance is to be measured and
                  reported in accordance with the MR response times described
                  below:

                  MR Response Times:

                  A = Immediate Attention - Resolution within 24 hours

                  B = Resolution 4 to 7 Days - Unguidables

                  C = Resolution 2 to 3 Weeks

                  D = Resolution 1 to 2 Months - Changes Which Need to be
                  Made

                  R = Resend (Files) within 6 Hours

                  All times refer to mutual business work days/hours

         4.4.5 Data Packs

         BellSouth will transmit to MCIm all packs error free in the format
         agreed.

         Measurement:

                  N = Total Number of Data Packs Sent Error Free
                      ------------------------------------------
                  D = Total Number of Data Packs Sent

                                                           Attachment VIII -- 54
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

          Target:          96% of all Packs transmitted in a calendar month will
                           be accepted.

         4.5 REPORTING

                  4.5.1 Left Blank Intentionally.

                  4.5.2 Left Blank Intentionally.

                           4.5.2.1 Left Blank Intentionally.

Section 5. Maintenance

         5.1 GENERAL REQUIREMENTS
         For maintenance, the parties agree to implement the BellSouth approved
         EBI standard within 12 months of the signing of this Agreement. MCIm
         understands that within such 12 month period BellSouth may not be able
         to make full implementation of the approved EBI standard, and provided
         BellSouth uses its best efforts to fully implement such standard as
         soon as possible, MCI agrees to accept less than full implementation at
         the conclusion of the 12 month period. MCI further agrees to accept on
         an interim basis, until such time as EBI is implemented, the interfaces
         approved by BellSouth.

                  5.1.1 BellSouth shall provide repair, maintenance, testing,
                  and surveillance for all Telecommunications Services and
                  unbundled Network Elements and Combinations in accordance with
                  the terms and conditions of this Agreement.

                           5.1.1.1 During the term of this Agreement, BellSouth
                           shall provide necessary maintenance business process
                           support as well as those technical and systems
                           interfaces required to enable MCIm to provide at
                           least the same level and quality of service for all
                           services for resale, functions, features,
                           capabilities and unbundled elements or combinations
                           of elements as BellSouth provides itself, its
                           subscribers any of its Affiliated or subsidiaries or
                           any other entity. BellSouth shall provide MCIm with
                           the same level of maintenance support as BellSouth
                           provides itself in accordance with standards and
                           performance measurements that are at least equal to
                           the highest level of standards and/or performance
                           measurements that BellSouth uses and/or which are
                           required by law, regulatory agency, or by

                                                           Attachment VIII -- 55
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  BellSouth's own internal procedures, whichever are the most
                  rigorous. These standards shall apply to the quality of the
                  technology, equipment, facilities, processes, and techniques
                  (including, but not limited to, such new architecture,
                  equipment, facilities, and interfaces as BellSouth may deploy)
                  that BellSouth provides to MCIm under this Agreement.

                  5.1.1.2 Until an Electronic Interface is available, BellSouth
                  shall provide access numbers to the state specific TRC
                  (Trouble Reporting Center) based on class of service for MCIm
                  to report via telephone maintenance issues and trouble reports
                  twenty-four (24) hours a day and seven (7) days a week.

                  5.1.1.3 BellSouth shall provide MCIm maintenance dispatch
                  personnel on the same schedule that they provide their own
                  subscribers.

                  5.1.2 MCIm shall handle all interaction with MCIm subscribers
                  including all calls regarding service problems, establishing
                  appointments pursuant to Section 5.1.11, and notifying the
                  subscriber of trouble status and resolution, unless otherwise
                  authorized by MCIm.

         5.1.3 BellSouth shall cooperate with MCIm to meet maintenance standards
         set forth in this Attachment for all Telecommunications Services,
         unbundled network elements and Combinations ordered under this
         Agreement. Such maintenance standards shall include, without
         limitation, standards for testing, network management, call gapping,
         and notification of upgrades as they become available.

         5.1.4 All BellSouth employees or contractors who perform repair service
         for MCIm subscribers shall follow at a minimum, procedures and
         protocols which ensure that: (1) BellSouth employees or contractors
         shall perform repair service that is at least equal in quality to that
         provided to BellSouth subscribers; (2) trouble calls from MCIm
         subscribers shall receive response time priority that is at least equal
         to that of BellSouth subscribers and shall be handled on a "first come
         first served" basis regardless of whether the subscriber is an MCIm
         subscriber or a BellSouth subscriber.

         5.1.5 For services provided through resale, BellSouth agrees to

                                                           Attachment VIII -- 56
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  provide MCIm with scheduled maintenance for residence and
                  small business customers, consistent with that which it
                  provides its own customers. BellSouth agrees to provide MCIm
                  written notification of Central Office conversions and such
                  conversions will occur after midnight and before 4 A.M.

                  BellSouth shall negotiate the release of any scheduled and
                  non-scheduled maintenance for Unbundled Network Elements or
                  Large Business Subscribers' service with MCIm prior to any
                  activity which may impact those services.

                  For services provided through resale, the BellSouth agrees to
                  provide scheduled maintenance for residence and small business
                  subscribers, consisting of cable throws, performed with test
                  sets which prevent the subscribers'services from being
                  interrupted during the activity. BellSouth shall monitor
                  individual cutover work to insure that the service is not in
                  use prior to the cut. Central office conversions shall be
                  publicized through the media and will occur after midnight and
                  before 4:00 A.M., unless MCIm is provided with written
                  notification.

                  For misdirected calls, BellSouth and MCIm shall advise
                  customers to contact MCIm and BellSouth, respectively, and
                  offer the customer the contact number upon request.

                  5.1.6 Left Blank Intentionally

                  5.1.7 Left Blank Intentionally

                  5.1.8 BellSouth shall inform MCIm of repair completion and
                  trouble reason as soon as possible after restoration of
                  network elements, or Combinations, and any other trouble
                  reports by MCIm. Notification should be provided via
                  electronic interface, when available.

                  5.1.9 BellSouth and MCIm shall mutually develop escalation
                  procedures to be followed if, in MCIm's judgment, any
                  performance standard defined in this Agreement is not met for
                  any individual trouble report. The escalation procedures to be
                  provided shall include telephone numbers of BellSouth
                  management personnel who are responsible for maintenance
                  issues and who will be contacted when a trouble condition is
                  escalated.

                                                           Attachment VIII -- 57
<PAGE>

                  MCImetro - BellSouth Mississippi Interconnection Agreement

                  5.1.10 BellSouth and MCIm shall mutually develop procedures to
                  establish the conditions under which a root cause analysis
                  will be performed and the methods by which the results will be
                  conveyed to MCIm.

                  5.1.11 Dispatching of BellSouth technicians to MCIm subscriber
                  premises shall be accomplished by BellSouth pursuant to a
                  request received from MCIm. MCIm shall be able to schedule
                  appointment windows based on load. The electronic interface
                  established pursuant to subsection 5.2 shall provide the
                  capability of allowing MCIm to receive trouble reports,
                  analyze and sectionalize the trouble, determine whether it is
                  necessary to dispatch a service technician to the subscriber'
                  s premises, and verify by disposition codes or narratives any
                  actual work completed on the subscriber's premises.

                  5.1.12 BellSouth shall supply MCIm with a unique number, which
                  may be the customer's actual number, to identify each MCI
                  initial trouble report opened. For repeat trouble reports, if
                  the previous trouble was within a 30 day period, the report
                  will be flagged as a repeat report automatically.

                  5.1.13 Left Blank Intentionally

                  5.1.14 Where BellSouth uses 611 for its own customers,
                  BellSouth shall make available to MCIm the ability to route
                  611 repair calls dialed by MCIm subscribers directly to the
                  MCIm repair center. Where BellSouth does not employ 611, MCIm
                  may establish at its discretion a 7 or 10 digit toll free
                  number for access to its repair center.

                  5.1.15 Until such information is available via an Electronic
                  Interface, BellSouth l will notify MCIm upon completion of
                  trouble report. The report shall not be considered closed
                  until such notification is made. MCIm will contact its
                  subscriber to determine if repairs were completed and confirm
                  the trouble no longer exists.

                  5.1.16 Additional Unbundling Requirements

                  5.1.16.1 When trouble is reported by a subscriber served
                  through unbundled network elements, MCIm will test its network
                  to identify any problems. If no problems are identified with
                  the MCIm network, MCIm will open a trouble report with
                  BellSouth. BellSouth shall then test its portion of

                                                           Attachment VIII -- 58
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  the network and perform repairs as required in the
                  timeframes set forth below in this Agreement.

                           5.1.16.1.1 MCIm will coordinate combined testing or
                           repair activities until trouble is resolved.
                           BellSouth shall provide repair updates to MCIm.

         5.2 SYSTEMS INTERFACES AND INFORMATION EXCHANGES

                  5.2.1.1 For line based (POTS) Resold Local Service, BellSouth
                  shall develop a real-time, on-line Electronic Interface for
                  access by MCIm to BellSouth's maintenance systems and
                  databases, in order to allow MCIm to: (i) receive "estimated
                  time to repair" ("ETTR") on a real-time basis; (ii) based on
                  the nature of the reported trouble, perform electronic test at
                  time of entry and provide test results to MCIm; and (iii)
                  provide final closure on trouble tickets entered into
                  BellSouth maintenance system for an MCIm subscriber. This
                  capability will be deployed by March 31, 1997.

                  In addition BellSouth agrees to continue to develop the
                  electronic interface capability to provide MCIm with ability
                  to: (iv) receive timely notification in the event a repair
                  person is unable to be present for, or anticipates missing, a
                  scheduled repair appointment; and (v) retrieve all applicable
                  time and material charges at the time of ticket closure
                  (itemized by time spent, price of materials used, procedures
                  employed, amounts incurred in each such category, and total by
                  customer, per event).

                  5.2.1.2 As an option to the above, MCIm may opt to use the
                  existing Electronic Communications gateway interface for line
                  based (POTS) Resold Local Service. This interface will allow
                  MCIm maintenance personnel and customer services
                  representatives to perform the following functions for MCIm
                  subscribers: (i) enter a new trouble ticket into the BellSouth
                  maintenance system for an MCIm subscriber; (ii) limited
                  ability to retrieve and track current status on all MCIm
                  subscriber repair tickets; and (iii) provide final closure on
                  trouble tickets entered into BellSouth's maintenance system
                  for an MCIm subscriber.

                  For local services provisioned via the Access Service

                                                           Attachment VIII -- 59
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  Request (ASR) process, the Electronic Communications gateway
                  interface may be used.

         5.2.2    BellSouth shall perform all testing for Resale Services.

                  5.2.2.1 Until the electronic interface with MCIm is fully
                  operational, BellSouth shall provide test results to MCIm, if
                  appropriate, for trouble clearance. When the electronic
                  interface with MCIm is fully operational, BellSouth shall give
                  MCI the ability to retrieve such results via the electronic
                  interface. In all instances, BellSouth will provide MCIm with
                  the disposition of the trouble.

                  5.2.2.2 If BellSouth initiates trouble handling procedures it
                  will bear all costs associated with that activity. If MCIm
                  requests the trouble dispatch then MCIm will bear the cost.

         5.2.3 Until such information is available via the Electronic Interface,
         BellSouth shall provide to MCIm the ability to obtain the status on
         open maintenance trouble reports via telephone or by another interface
         as the parties may mutually agree. BellSouth agrees to provide the
         status of residence and small business trouble reports upon MCIm's
         request.

         5.2.4 BellSouth agrees to provide to MCIm the status for open
         maintenance trouble reports for large business subscribers anytime the
         status of the trouble report changes or at MCIm's request.

         5.2.5 Until the electronic interface with MCIm is fully operational,
         BellSouth agrees that MCIm may call BellSouth to verify central office
         features and functions as they relate to an open trouble report.
         BellSouth agrees to work with MCIm on the initial trouble report to
         isolate the cause of the trouble and, where possible, resolve the
         feature/function related trouble at that time.

         5.2.6 BellSouth agrees to advise MCIm of any central office failure
         that is known at the time of any inquiry or trouble report. BellSouth
         agrees to continue to use its best efforts to implement a process which
         will provide automatic notification to MCIm at the time of trouble
         ticket entry.

         5.2.7 BellSouth agrees to provide an Estimated Time To Repair

                                                           Attachment VIII -- 60
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

         (ETTR), an appointment time or commitment time, as appropriate, on all
         residence and small business trouble reports.

         5.2.8 BellSouth agrees to develop, with MCIm's cooperation, mutually
         acceptable workcenter interface agreements to document methods and
         procedures for interim and final interfaces for each service within
         sixty (60) days following the effective date of this Agreement or
         MCIm's notice to BellSouth of its initiation of that service. The sixty
         (60) day period shall be extended to the extent of any delay
         attributable to MCIm.

5.3 PROCEDURES

         5.3.1 Maintenance charges for premises visits by BellSouth employees or
         contractors shall be billed to MCIm and not to the subscriber.

                  5.3.1.1 If additional work is required, BellSouth employees or
                  contractors shall call MCIm from subscriber premises so that
                  MCIm can schedule a new appointment with BellSouth and
                  subscriber at the same time.

                  5.3.1.2 BellSouth employees or contractors shall present the
                  subscriber with an unbranded form, or MCIm provided MCIm
                  branded form, detailing the time spent, the materials used and
                  an indication that the trouble has either been resolved, or
                  that additional work will be necessary.

                  5.3.1.3 The BellSouth employees or contractors shall use its
                  best efforts obtain the subscriber's signature upon said
                  form, and use the signed form to input maintenance charges
                  into the BellSouth repair and maintenance database (accessible
                  by way of electronic interface). These charges shall include
                  any charges for inside wiring work by BellSouth employees or
                  contractors.

         5.4 Performance Measurements and Reporting

                  5.4.1 Time to Restore

                  Measures average time it takes to restore to service Local

                                                           Attachment VIII -- 61
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  Services, Network Elements, or Combinations.

                  Measurement:

                             N = Total Duration Time
                                 -------------------
                             D = Total Troubles

           For Specials and Local Interconnection / Trunking:

                           N = Responsible Duration Time
                               -------------------------
                           D = Total Troubles

                  To the extent MCIm has requested that BellSouth measure the
                  time to restore Local Services, Network Elements or
                  Combinations, separated between time to restore where no
                  dispatch is required, time to restore where dispatch is
                  required and time to restore a service impairment, and in
                  addition MCIm has requested BellSouth to provide these
                  measurements delineated in certain hourly intervals, BellSouth
                  is agreeable to meeting this request for hourly intervals as
                  delineated by MCIm, subject to an estimated one-time cost of
                  $20,000.00 and a monthly recurring cost of $500.00. MCIm
                  agrees to give BellSouth thirty (30) days written notice of
                  its desire for BellSouth to provide this measurement and,
                  subject to final agreement on cost (one-time and monthly),
                  BellSouth will provide it as requested, within ninety (90)
                  days unless otherwise agreed.

                  5.4.2 Repeat Troubles

                  Measurers trouble reports from the same customer in a 30 day
                  period.

                           N = Total Repeats (less than) 30 days
                               ---------------------------------
                           D = Total Troubles

                  5.4.3 Trouble Resolution Notification

                  BellSouth shall inform MCIm of the restoration of Local
                  Service, Network Element, or Combination after an outage has
                  occurred by means of a telephone call until such time as a
                  mechanized means

                                                           Attachment VIII -- 62
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  of notification becomes available.

                  5.4.4 MCIm will transmit repair calls to the BellSouth repair
                  bureau by telephone until it is able to make use of the
                  Electronic Interfaces pursuant to this Attachment VIII.
                  BellSouth shall measure the average length of time it takes
                  for the BellSouth repair bureau attendant to answer the
                  telephone.

                  5.4.5 Missed Appointments

                  Measures when BellSouth misses meeting end user appointments
                  that require a premise visit.

                  Measurement:

                           N = Total Appointments met
                               ----------------------
                           D = Total Appointments set

                  5.4.6 Report Rate

                  Measures the frequency of troubles reported within BellSouth's
                  network.

                  Measurement:

                           N = Number of Trouble Reports per month
                               -----------------------------------
                           D = Total number of lines

         SECTION 6. MISCELLANEOUS SERVICES & Functions

                  6.1 General Requirements

                           6.1.1 Basic 911 and E911 General Requirements

                                    6.1.1.1 Basic 911 and E911 provides a caller
                                    access to the appropriate emergency service
                                    bureau by dialing a 3-digit universal
                                    telephone number (911). Basic 911 and E911
                                    access from Local Switching shall be
                                    provided to MCIm in accordance with the
                                    following:

                                    6.1.1.2 E911 shall provide additional
                                    routing flexibility for

                                                           Attachment VIII -- 63
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           911 calls. E911 shall use subscriber data, contained
                           in the Automatic Location Identification/ Data
                           Management System (ALI/DMS) and the E911 tandem
                           switch, to determine to which Public Safety Answering
                           Point (PSAP) to route the call.

                           6.1.1.3 If available, BellSouth shall offer a third
                           type of 911 service, S911. All requirements for E911
                           also apply to S911 with the exception of the type of
                           signaling used on the interconnection trunks from the
                           local switch to the S911 tandem.

                           6.1.1.4 Basic 911 and E911 functions provided to MCIm
                           shall be at least at parity with the support and
                           services that BellSouth provides to its subscribers
                           for such similar functionality.

                           6.1.1.5 Basic 911 and E911 access from Local
                           Switching shall be provided to MCIm in accordance
                           with the following:

                                    6.1.1.5.1 BellSouth shall conform to all
                                    state regulations concerning emergency
                                    services.

                                    6.1.1.5.2 For E911, BellSouth shall receive
                                    data from MCIm as described in the MCIm
                                    GUIDE (electronically via FTS). Errors will
                                    be mechanically faxed to MCIm promptly after
                                    the errors are detected by the update
                                    process. MCIm will transmit daily update
                                    files for "batch" processing within 24 hours
                                    of receipt of a "good file."

                                    6.1.1.6 BellSouth shall provide for overflow
                                    911 traffic to be routed to BellSouth
                                    Operator Services or, at MCIm's discretion,
                                    directly to MCIm operator services or to a
                                    seven digit number as provided by BellSouth
                                    and/or the appropriate public safety agency.

                                    6.1.1.7 Basic 911 and E911 access from the
                                    MCIm local switch shall be provided to MCIm
                                    in accordance with the following:

                                            6.1.1.7.1 Subject to mutual
                                            agreement, BellSouth shall
                                            interconnect direct trunks from the
                                            MCIm network to the E911 PSAP, or
                                            the E911 tandems as designated by
                                            MCIm. Such trunks may alternatively

                                                           Attachment VIII -- 64
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                            be provided by MCIm, without the
                                            selective routing function.

                                            6.1.1.7.2 In government
                                            jurisdictions where BellSouth has
                                            obligations under existing
                                            Agreements as the primary provider
                                            of the 911 System to the county,
                                            MCIm shall participate in the
                                            provision of the 911 System as
                                            follows:

                                                     6.1.1.7.2.1 Each party
                                                     shall be responsible for
                                                     those network portions of
                                                     the 911 System for which it
                                                     has control, including any
                                                     necessary maintenance to
                                                     each party's portion of
                                                     the 911 System.

                                                     6.1.1.7.2.2 Host BellSouth
                                                     shall be responsible for
                                                     maintaining the E-911
                                                     database BellSouth
                                                     including validating MCIm
                                                     updates against MSAG and
                                                     posting valid updates to
                                                     E911 database. Errors will
                                                     be returned to MCIm for
                                                     correction and transmission
                                                     of valid updates.

                           6.1.1.7.3 If a third party is the primary service
                           provider to a government agency, MCIm shall negotiate
                           separately with such third party with regard to the
                           provision of 911 service to the agency. All relations
                           between such third party and MCIm are totally
                           separate from this Agreement and BellSouth makes no
                           representations on behalf of the third party.

                           6.1.1.7.4 If MCIm or Affiliate is the primary service
                           provider to a government agency, MCIm and BellSouth
                           shall negotiate the specific provisions necessary for
                           providing 911 service to the agency and shall include
                           such provisions in an amendment to this Agreement.

                           6.1.1.7.5 Interconnection and database access shall
                           be priced as specified in Attachment I or at any rate
                           charged to other interconnected carriers, whichever
                           is lower.

                           6.1.1.7.6 BellSouth shall comply with established,
                           competitively neutral intervals for installation of
                           facilities, including any collocation facilities,
                           diversity requirements, etc.

                                                           Attachment VIII -- 65
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           6.1.1.7.7 Where it may be appropriate for BellSouth
                           to update the ALI database, BellSouth shall update
                           such database with MCIm data in an interval no less
                           than is experienced by BellSouth subscribers, or than
                           for other carriers, whichever is faster, at no
                           additional cost.

                           6.1.1.8 BellSouth shall provide to MCIm, where
                           available, no later than fifteen (15) days after the
                           Effective Date of this Agreement, the emergency
                           public agency (e.g. police, fire, rescue, poison, and
                           bomb) telephone numbers linked to all NPA NXXs for
                           the states in which they provide service. Such
                           information shall be used solely for purposes of
                           handling emergency calls.

                           6.1.1.9 BellSouth shall transmit to MCIm all changes,
                           alterations, modifications, and updates to the
                           emergency public agency telephone numbers linked to
                           all NPA NXX's when known.

                           6.1.1.10 The following are Basic 911 and E911
                           Database Requirements:

                                    6.1.1.10.1 The TN data is managed in ALI by
                                    BellSouth, but the responsibility for
                                    providing the data resides with each Local
                                    Service Provider.

                                    6.1.1.10.2 Copies of the MSAG shall be
                                    provided within seven (7) business days from
                                    the time requested and provided on magnetic
                                    tape or paper.

                                    6.1.1.10.3 MCIm shall be solely responsible
                                    for providing MCIm database records to
                                    BellSouth for inclusion in BellSouth's ALI
                                    database on a timely basis.

                                    6.1.1.10.4 BellSouth and MCIm shall arrange
                                    for the automated input and periodic
                                    updating of the E911 database information
                                    related to MCIm end users as stated in the
                                    ALEC Guide (Local Exchange Users Guide for
                                    Facility Based Providers). BellSouth shall
                                    work cooperatively with MCIm to ensure the
                                    accuracy of the data transfer by verifying
                                    it against the Master Street Address Guide
                                    (MSAG). BellSouth

                                                           Attachment VIII -- 66
<PAGE>

                  MCImetro - BellSouth Mississippi Interconnection Agreement

                                    6.1.1.10.5 MCIm shall assign an E911
                                    database coordinator charged with the
                                    responsibility of forwarding MCIm end user
                                    ALI record information to BellSouth or via a
                                    third-party entity, charged with the
                                    responsibility of ALI record transfer. MCIm
                                    assumes all responsibility for the accuracy
                                    of the data that MCIm provides to BellSouth.

                                    6.1.1.10.6 MCIm shall provide information on
                                    new subscribers to BellSouth within one (1)
                                    business day of the order completion.
                                    BellSouth shall update the database within
                                    two (2) business days of receiving the data
                                    from MCIm. If BellSouth detects an error in
                                    the MCIm provided data, the data shall be
                                    returned to MCIm within two (2) business
                                    days from when it was provided to BellSouth.
                                    MCIm shall respond to requests from
                                    BellSouth to make corrections to database
                                    record errors by uploading corrected records
                                    within two (2) business days.

                                    6.1.1.10.7 BellSouth agrees to treat all
                                    data on MCIm subscribers provided under this
                                    Agreement as strictly confidential and to
                                    use data on MCIm subscribers only for the
                                    purpose of providing E911 services.

                                    6.1.1.10.8 BellSouth shall adopt use of a
                                    Carrier Code (NENA standard five-character
                                    field) on all ALI records received from MCIm
                                    at such time as a NENA standard carrier
                                    codes is implemented. The Carrier Code will
                                    be used to identify the carrier of record in
                                    INP configurations.

                                    6.1.1.10.9 BellSouth shall identify which
                                    ALI databases cover which states, counties
                                    or parts thereof, and identify and
                                    communicate a Point of Contact for each.

                           6.1.1.11 Left blank intentionally

                           6.1.1.12 The following are basic 911 and E911 Network
                           Requirements:

                                    6.1.1.12.1 BellSouth, at MCIm's option,
                                    shall provide a minimum of two (2) E911
                                    trunks per Numbering

                                                           Attachment VIII -- 67
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    Plan Area (NPA) code, or that quantity which
                                    will maintain parity with the BellSouth's
                                    grade of service, whichever is the higher
                                    grade of service. These trunks will be
                                    dedicated to routing 911 calls from MCIm's
                                    switch to a BellSouth selective router.

                                    6.1.1.12.2 BellSouth shall provide the
                                    selective routing of E911 calls received
                                    from MCIm's switching office where
                                    feasible. This includes the ability to
                                    receive the ANI of MCIm's subscriber,
                                    selectively route the call to the
                                    appropriate PSAP, and forward the
                                    subscriber's ANI to the PSAP. BellSouth
                                    shall provide MCIm with the appropriate CLLI
                                    codes and specifications regarding the
                                    tandem serving area associated addresses and
                                    meetpoints in the network.

                                    6.1.1.12.3 Selective Routing Boundary
                                    documentation shall be available to MCIm.
                                    Documentation shows the boundary around the
                                    outside of the set of exchange areas served
                                    by that selective router. The documentation
                                    provides MCIm the information necessary to
                                    set up its network to route E911 callers to
                                    the correct selective router.

                                    6.1.1.12.4 MCIm shall ensure that its switch
                                    provides an eight-digit ANI consisting of an
                                    information digit and the seven-digit
                                    exchange code. MCIm shall also ensure that
                                    its switch provides the line number of the
                                    calling station. Where applicable and
                                    mutually agreed to, MCIm shall send a
                                    ten-digit ANI to BellSouth.

                                    6.1.1.12.5 Each ALI discrepancy report shall
                                    be transmitted by BellSouth to MCIm for
                                    corrective action.

                                    6.1.1.12.6 The BellSouth controlling the 911
                                    network should provide MCIm with a detailed
                                    written description of the following
                                    information on a one time basis:

                                            6.1.1.12.6.1 When requested by MCIm,
                                            geographic boundaries of the
                                            BellSouth exchange service areas,
                                            and assistance in identifying the
                                            geographic boundaries of the

                                                           Attachment VIII -- 68
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           MCImetro - BellSouth Mississippi Interconnection Agreement

                                            government entities and PSAPs, as
                                            necessary.

                                            6.1.1.12.6.2 When requested by MCIm,
                                            LECs rate centers/exchanges, where
                                            "Rate Center" is defined as a
                                            geographically specified area used
                                            for determining mileage dependent
                                            rates in the Public Switched
                                            Telephone Network.

                                            6.1.1.12.6.3 Technical
                                            specifications for network
                                            interface, Technical specifications
                                            for database loading and
                                            maintenance.

                                    6.1.1.12.7 Left Blank Intentionally

                                    6.1.1.12.8 BellSouth shall begin restoration
                                    of E911 and/or E911 trunking facilities
                                    immediately upon notification of failure or
                                    outage. BellSouth must provide priority
                                    restoration of trunks or networks outages on
                                    the same terms/conditions it provides itself
                                    and without the imposition of
                                    Telecommunications Service Priority (TSP).

                                    6.1.1.12.9 Left Blank Intentionally

                                    6.1.1.12.10 Left blank intentionally

                                    6.1.1.12.11 Diversity will be maintained or
                                    upgraded to utilize the highest level of
                                    diversity available in the network.

                                    6.1.1.12.12 Equipment and circuits used for
                                    911 shall be monitored at all times.
                                    Monitoring of circuits shall be done to the
                                    individual circuit level. Monitoring shall
                                    be conducted by BellSouth for trunks between
                                    the tandem and all associated PSAPs.

                                    6.1.1.12.13 Repair service shall begin
                                    immediately upon receipt of a report of a
                                    malfunction. Repair service includes testing
                                    and diagnostic service from a remote
                                    location, dispatch of or in-person visit(s)
                                    of personnel. Technicians will be dispatched
                                    without delay.

                                    6.1.1.12.14 All 911 trunks must be capable
                                    of

                                                           Attachment VIII -- 69
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           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    transmitting and received Baudot code
                                    necessary to support the use of
                                    Telecommunications Devices for the Deaf
                                    (TTY/TDDs).

                           6.1.1.13 Basic 911 and E911 Additional Requirements

                                    6.1.1.13.1 All MCIm lines that have been
                                    ported via INP shall reach the correct PSAP
                                    when 911 is dialed. BellSouth shall send
                                    both the ported number and the MCIm number
                                    (if both are received from MCIm) to the
                                    PSAP.

                                    6.1.1.13.2 BellSouth, where available, shall
                                    work with the appropriate government agency
                                    to provide MCIm the ten-digit POTS number of
                                    each PSAP which sub-tends each BellSouth
                                    selective router/911 tandem to which MCIm is
                                    interconnected.

                                    6.1.1.13.3 BellSouth shall notify MCIm 48
                                    hours in advance of any scheduled testing or
                                    maintenance affecting MCIm 911 service, and
                                    provide notification as soon as possible of
                                    any unscheduled outage affecting MCIm 911
                                    service.

                                    6.1.1.13.4 MCIm shall be responsible for
                                    reporting all errors, defects and
                                    malfunctions to BellSouth. BellSouth shall
                                    use its best efforts to provide MCIm with
                                    the point of contact for reporting errors,
                                    defects, and malfunctions in the service and
                                    shall also provide escalation contacts
                                    within thirty (30) days of the Effective
                                    Date.

                                    6.1.1.13.5 MCIm may enter into subcontracts
                                    with third parties, including MCIm
                                    Affiliates, for the performance of any of
                                    MCIm' s duties and obligations stated
                                    herein.

                                    6.1.1.13.6 Within ninety (90) days of a
                                    BellSouth decision to implement SS7
                                    signaling, BellSouth shall notify MCIm of
                                    such decision.

                                    6.1.1.13.7 BellSouth shall provide
                                    notification of any pending tandem moves,
                                    NPA splits, or scheduled maintenance
                                    outages, with enough time to react.

                                                           Attachment VIII -- 70
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    6.1.1.13.8 BellSouth shall notify MCIm
                                    within 30 days of BellSouth's decision to
                                    implement "reverse ALI" inquiries by public
                                    safety entities.

                                    6.1.1.13.9 BellSouth shall continue its
                                    existing process for the management of NPA
                                    splits by populating the ALI database with
                                    the appropriate new NPA codes.

                                    6.1.1.13.10 BellSouth must provide the
                                    ability for MCIm to update 911 database with
                                    end user information for lines that have
                                    been ported via INP or NP.

                                    6.1.1.13.11 MCIm may, at its discretion,
                                    further request additional and/or modified
                                    reporting as business needs demand.

                  6.1.2    DIRECTORY ASSISTANCE SERVICE

                           6.1.2.1 BellSouth shall provide for the routing of
                           directory assistance calls (including but not limited
                           to 411, 555-1212, NPA-555-1212) dialed by MCIm
                           subscribers directly to either the MCIm DA service
                           platform or BellSouth DA service platform as
                           specified by MCIm. BellSouth shall provide MCIm with
                           selective routing via Line Class Codes. Further, MCIm
                           and BellSouth shall continue to work with the
                           appropriate industry groups to develop a long term
                           solution for selective routing.

                           6.1.2.2 MCIm subscribers shall be provided, subject
                           to section 6.1.2.1, above, the capability by
                           BellSouth to dial the same telephone numbers for
                           access to MCIm Directory Assistance that BellSouth
                           subscribers to access BellSouth Directory Assistance.

                           6.1.2.3 BellSouth shall provide, subject to section
                           6.1.2.1, above, Directory Assistance functions and
                           services to MCIm for its subscribers as described
                           below until, at MCIm's discretion, BellSouth routes
                           calls to the MCIm Directory Assistance Services
                           platform.

                                    6.1.2.3.1 BellSouth agrees to provide MCIm
                                    subscribers with the same Directory
                                    Assistance

                                                           Attachment VIII -- 71
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    service available to BellSouth subscribers.

                                    6.1.2.3.2 BellSouth shall notify MCIm in
                                    advance of any changes or enhancements to
                                    its DA service, and shall make available
                                    such service enhancements on a
                                    non-discriminatory basis to MCIm.

                                    6.1.2.3.3 BellSouth shall provide Directory
                                    Assistance to MCIm subscribers in accordance
                                    with BellSouth's internal operating
                                    BellSouth procedures and standards, which
                                    shall, at a minimum, comply with accepted
                                    professional and industry standards.

                                    6.1.2.3.4 BellSouth shall provide MCIm with
                                    the same level of support for the
                                    provisioning of Directory Assistance as
                                    BellSouth provides itself. Quality of
                                    service standards shall be in accordance
                                    with standards and performance measurements
                                    that are at least equal to the highest level
                                    of standards and/or performance measurements
                                    that BellSouth uses and/or which are
                                    required by law, regulatory agency, or by
                                    BellSouth's own internal procedures,
                                    whichever are the most rigorous.

                                    6.1.2.3.5 Service levels shall comply, at a
                                    minimum, with State Regulatory Commission
                                    requirements for number of rings to answer,
                                    average work time, and disaster recovery
                                    options.

                                    6.1.2.3.6 BellSouth agrees to maintain an
                                    adequate operator work force based on
                                    service standards described in sections
                                    6.1.2.3.4 and 6.1.2.3.5

                                    6.1.2.3.7 Left Blank Intentionally

                                    6.1.2.3.8 Directory Assistance services
                                    provided by BellSouth to MCIm subscribers
                                    shall be branded as required by MCIm;
                                    provided, however, that if for any reason
                                    BellSouth finds it is not possible to
                                    implement MCIm's branding request, then
                                    BellSouth shall revert to generic branding
                                    for all local exchange service providers,
                                    including itself. Branding includes
                                    front-end, back-end, and non-branding to be
                                    determined by MCIm.

                                    6.1.2.3.9 BellSouth shall provide the
                                    following minimum Directory Assistance
                                    capabilities to MCIm's subscribers:

                                                           Attachment VIII -- 72
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                            6.1.2.3.9.1 A minimum of two
                                            subscriber listings and/or addresses
                                            or BellSouth parity per MCIm
                                            subscriber request.

                                            6.1.2.3.9.2 Name and address to MCIm
                                            subscribers upon request, except for
                                            unlisted numbers, in the same states
                                            where such information is provided
                                            to BellSouth subscribers.

                                            6.1.2.3.9.3 Upon request, call
                                            completion to the requested number
                                            for local and intraLATA toll calls
                                            shall be sent, subject to section
                                            6.1.2.1. above, to the network
                                            specified by MCIm. Rating and
                                            billing shall be done by MCIm.

                                            6.1.2.3.9.4 Populate the Directory
                                            Assistance database in the same
                                            manner and in the same time frame as
                                            for BellSouth subscribers.

                                            6.1.2.3.9.5 Any information provided
                                            by a Directory Assistance Automatic
                                            Response Unit (ARU) shall be
                                            repeated the same number of times
                                            for MCIm subscribers as for
                                            BellSouth's subscribers.

                                            6.1.2.3.9.6 When requested by MCIm,
                                            BellSouth shall provide instant
                                            credit on directory assistance calls
                                            as provided to BellSouth
                                            subscribers. BellSouth

                           6.1.2.4 BellSouth shall provide data regarding
                           billable events as mutually agreed upon by MCIm and
                           BellSouth.

                     6.1.3 Operator Services

                           6.1.3.1 BellSouth shall provide for the routing of
                           local operator services calls (including but not
                           limited to 0+, 0-) dialed by MCIm subscribers
                           directly to either the MCIm operator service platform
                           or BellSouth operator service

                                                           Attachment VIII -- 73
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                           platform as specified by MCIm. BellSouth shall
                           provide MCIm with selective routing via Line Class
                           Codes. Further, MCIm and BellSouth shall continue to
                           work with the appropriate industry groups to develop
                           a long term solution for selective routing.

                           6.1.3.2 MCIm subscribers shall be provided, subject
                           to section 6.1.3.1, above, the capability by
                           BellSouth to dial the same telephone numbers to
                           access MCIm operator service that BellSouth
                           subscribers dial to access BellSouth operator
                           service.

                           6.1.3.3 BellSouth shall provide, subject to section
                           6.1.3.1, above, Operator Services to as described
                           below until, at MCIm's discretion, BellSouth routes
                           calls to the MCIm Local Operator Services platform.

                                    6.1.3.3.1 BellSouth agrees to provide MCIm
                                    subscribers the same Operator Services
                                    available to BellSouth subscribers.
                                    BellSouth shall make available its service
                                    enhancements on a non-discriminatory basis..

                                    6.1.3.3.2 Operator Services provided to MCIm
                                    subscribers shall be branded as required by
                                    MCIm; provided however, that if for any
                                    reason BellSouth finds it is not possible to
                                    implement MCIm's branding request, then
                                    BellSouth shall revert to generic branding
                                    for all local exhcange service providers,
                                    including itself. Branding options include
                                    front-end, back-end, and non-branding as
                                    specified by MCIm.

                                    6.1.3.3.3 BellSouth shall provide the
                                    following minimum Operator Service
                                    capabilities to MCIm subscribers:

                                            6.1.3.3.3.1 BellSouth shall complete
                                            0+ and 0- dialed local calls.

                                            6.1.3.3.3.2 BellSouth shall complete
                                            0+ and 0- intraLATA toll calls.

                                            6.1.3.3.3.3 BellSouth shall complete
                                            calls that are billed to a calling
                                            card and MCIm shall designate to
                                            BellSouth the acceptable types of

                                                           Attachment VIII -- 74
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                            special billing for Special Calling
                                            Cards or credit cards that can be
                                            accepted.

                                            6.1.3.3.3.4 BellSouth shall complete
                                            person-to-person calls.

                                            6.1.3.3.3.5 BellSouth shall complete
                                            collect calls.

                                            6.1.3.3.3.6 BellSouth shall provide
                                            the capability for callers to bill
                                            to a third party and complete such
                                            calls.

                                            6.1.3.3.3.7 BellSouth shall complete
                                            station-to-station calls.

                                            6.1.3.3.3.8 BellSouth shall process
                                            emergency calls when the caller
                                            dials 0- in error.

                                            6.1.3.3.3.9 BellSouth shall process
                                            Busy Line Verify and Emergency Line
                                            Interrupt requests.

                                            6.1.3.3.3.10 BellSouth shall process
                                            emergency call trace, subject to
                                            mutual agreement of MCIm and
                                            BellSouth on applicable processes.

                                            6.1.3.3.3.11 BellSouth shall process
                                            operator-assisted directory
                                            assistance calls.

                                            6.1.3.3.3.12 Upon a subscriber
                                            request for either a rate quote or
                                            time and charges, BellSouth shall,
                                            through a neutral response, inquire
                                            of the subscriber from which carrier
                                            the rate or time and charges is
                                            requested. The operator will connect
                                            the call to that carrier.

                                            6.1.3.3.3.13 Left blank
                                            intentionally

                                            6.1.3.3.3.14 BellSouth shall route
                                            0- traffic to a "live" operator
                                            team.

                                            6.1.3.3.3.15 When requested by MCIm,
                                            BellSouth shall provide instant
                                            credit on

                                                           Attachment VIII -- 75
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                            operator services calls as provided
                                            to BellSouth subscribers.

                                            6.1.3.3.3.16 Caller assistance for
                                            the disabled in the same manner as
                                            provided to BellSouth subscribers.

                                            6.1.3.3.3.17 If and when available,
                                            BellSouth shall provide
                                            operator-assisted conference
                                            calling.

                           6.1.3.4 Left Blank Intentionally

                           6.1.3.5 Operator Service shall adhere to equal access
                           requirements when providing operator transfer
                           services.

                           6.1.3.6 BellSouth shall exercise at least the same
                           level of fraud control in providing Operator Service
                           to MCIm that BellSouth provides for its own operator
                           service.

                           6.1.3.7 BellSouth shall perform Billed Number
                           Screening when handling Collect, Third Party, and
                           Calling Card Calls, both for station to station and
                           person to person call types.

                           6.1.3.8 BellSouth shall provide service measurements
                           and accounting reports as mutually agreed by MCIm and
                           BellSouth.

                           6.1.3.9 Left Blank Intentionally

                           6.1.3.10 BellSouth shall direct subscriber account
                           and other similar inquiries to the subscriber service
                           center designated by MCIm, if requested by the
                           subscriber.

                           6.1.3.11 BellSouth shall provide an electronic feed
                           of subscriber call records in "EMR" format to MCIm in
                           accordance with Section 4 of this Attachment.

                           6.1.3.12 Left Blank Intentionally

                           6.1.3.13 Busy Line Verification and Emergency Line
                           Interrupt:

                                    6.1.3.13.1 BellSouth shall engineer its
                                    BLV/ELI facilities to accommodate the
                                    anticipated volume of

                                                           Attachment VIII -- 76
<PAGE>

                  MCImetro - BellSouth Mississippi Interconnection Agreement

                           BLV/ELI requests during the Busy Hour. MCIm may, from
                           time to time, provide its anticipated volume of
                           BLV/ELI requests to BellSouth. In those instances
                           when the BLV/ELI systems and databases become
                           unavailable, BellSouth shall promptly Inform MCIm.

                  6.1.3.14 BellSouth shall update the Line Information Data Base
                  (LIDB) for MCIm subscribers without charge. Additionally,
                  BellSouth must provide access to LIDB for validation of
                  collect, third party billed, and LEC card billed calls.

                  6.1.3.15 Where INP is deployed and when a BLV/BLI
                  request for a ported number is directed to a BellSouth
                  operator and the query is not successful (i.e., the request
                  yields an abnormal result) the operator shall confirm
                  whether the number has been ported and shall direct the
                  request to the appropriate operator.

                  6.1.3.16 Charges for services provided pursuant to Section
                  6.1.3 shall be as set forth in Attachment I.

         6.1.4   DIRECTORY ASSISTANCE AND LISTINGS SERVICE REQUESTS

                  6.1.4.1 These requirements pertain to BellSouthAE s DA and
                  Listings Service Request process that enables MCIm to (a)
                  submit MCIm subscriber information for inclusion in BellSouth
                  Directory Assistance and Directory Listings databases; (b)
                  submit MCIm subscriber information for inclusion in published
                  directories; and (c) provide MCIm subscriber delivery address
                  information to enable BellSouth to fulfill directory
                  distribution obligations.

                           6.1.4.1.1 BellSouth shall accept orders via
                           electronic interface in accordance with OBF Directory
                           Service Request standards (TCIF EDI Technical
                           Mapping) within - nine (9) months of final standard
                           adoption. In the interim, BellSouth shall create a
                           standard format and order process by which MCIm can
                           place an order via electronic exchange no later than
                           April 1, 1997.

                           6.1.4.1.2 BellSouth will provide to MCIm the
                           following Directory Listing Migration Options, valid
                           under all interconnection methods, including but not
                           limited to, Resale, Unbundled Network Elements and

                                                           Attachment VIII -- 77
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                Facilities-Based:

                                    6.1.4.1.2.1 Migrate with no Changes: Retain
                                    and transfer all white and transfer all
                                    yellow page listings for the subscriber in
                                    both DA and DL. Transfer ownership and
                                    billing for listings to MCIm.

                                    6.1.4.1.2.2 Migrate with Additions: Retain
                                    and transfer all white and transfer all
                                    yellow page listings for the subscriber in
                                    both DA and DL. Incorporate the specified
                                    additional listings order. Transfer
                                    ownership and billing for the listings to
                                    MCIm.

                                    6.1.4.1.2.3 Migrate with Deletions: Retain
                                    and transfer all white and transfer all
                                    yellow page listings for the subscriber in
                                    both DA and DL. Delete the specified
                                    listings from the listing order. Transfer
                                    ownership and billing for the listings to
                                    MCIm.

                           6.1.4.1.3 BellSouth shall enable MCIm to
                           electronically transmit multi-line listing orders.

                           6.1.4.1.4 Left blank intentionally

                           6.1.4.1.5 Left blank intentionally

                           6.1.4.1.6 Left blank intentionally

                           6.1.4.1.7 Based on changes submitted by MCIm,
                           BellSouth shall update and maintain directory
                           assistance and directory listings data for MCIm
                           subscribers who:

                                    6.1.4.1.7.1 Disconnect Service
                                    6.1.4.1.7.2 Change of Local Carrier
                                    6.1.4.1.7.3 Install Service
                                    6.1.4.1.7.4 Change any service which
                                    affects DA information
                                    6.1.4.1.7.5 Are Non-Published,
                                    Non-Listed, or Listed

                           6.1.4.1.8 BellSouth shall not charge for storage of

                                                           Attachment VIII -- 78
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    MCIm subscriber information in the DA and DL
                                    systems.

                                    6.1.4.1.9 MCIm shall not charge for storage
                                    of BellSouth subscriber information in the
                                    DA and DL systems.

                           6.1.5 Left blank intentionally

                           6.1.6 Directory Assistance Data

                                 6.1.6.1 BellSouth shall provide to MCIm, to the
                                 extent authorized, the residential, business,
                                 and government subscriber records used by
                                 BellSouth to create and maintain its Directory
                                 Assistance Data Base, in a non-discriminatory
                                 manner. MCIm may combine this element with any
                                 other Network Element for the provision of any
                                 Telecommunications Service.

                                 6.1.6.2 Upon request, BellSouth shall provide
                                 an initial load of subscriber records via
                                 electronic data transfer for ILECs, CLECs and
                                 independent Telcos included in their Directory
                                 Assistance Database, to the extent authorized.
                                 The NPAs included shall represent the entire
                                 BellSouth operating territory. The initial load
                                 shall reflect all data that is current as of
                                 one business day prior to the provision date.

                                 6.1.6.3 BellSouth shall provide MCIm, to the
                                 extent authorized, a complete list of ILECs,
                                 CLECs, and independent Telcos that provided
                                 data contained in the database.

                                 6.1.6.4 All directory assistance data shall be
                                 provided in the format as specified in
                                 "Directory Assistance Data Information
                                 Exchanges and Interfaces" below or in Bellcore
                                 standard F20 format.

                                 6.1.6.5 On a daily basis, BellSouth shall
                                 provide updates (end user and mass) to the
                                 Listing Information via electronic data
                                 transfer. Updates shall be current as of one
                                 business day prior to the date provided to
                                 MCIm.

                                 6.1.6.6 Left blank intentionally


                                                           Attachment VIII -- 79
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                 6.1.6.7 DA data shall specify whether the
                                 subscriber is a residential, business, or
                                 government subscriber. Additionally, data must
                                 include all levels of indentation and all
                                 levels of information specified in "Directory
                                 Assistance Data Information Exchanges and
                                 Interfaces" below.

                                 6.1.6.8 DA data shall be provided on the same
                                 terms and conditions that BellSouth provides to
                                 itself or other third parties, and at the same
                                 rates that BellSouth provides to other third
                                 parties.

                                 6.1.6.9 BellSouth shall provide complete
                                 refresh of the DA data upon mutual agreement of
                                 BellSouth and MCIm and subject to applicable
                                 charges pursuant to Attachment I. 6.1.6.10 MCIm
                                 and BellSouth, upon mutual agreement, will
                                 designate a Technically Feasible point at which
                                 the data will be provided.

                      6.2 SYSTEMS INTERFACES AND EXCHANGES

                           6.2.1 BASIC 911 AND E911 INFORMATION EXCHANGES AND
                           INTERFACES

                                 6.2.1.1 BellSouth shall provide MCIm a data
                                 link to the ALI/DMS database or permit MCIm to
                                 provide its own data link to the ALI/DMS
                                 database. BellSouth shall provide error reports
                                 from the ALI/DMS database to MCIm after MCIm
                                 inputs information into the ALI/DMS database.
                                 Alternately, MCIm may utilize BellSouth or a
                                 third party entity to enter through the service
                                 order process subscriber information into the
                                 database on a demand basis, and validate
                                 subscriber information on a demand basis.

                                 6.2.1.2 BellSouth and MCIm shall arrange for
                                 the automated input and periodic updating of
                                 the E911 database information related to MCIm
                                 end users as stated in the ALEC Guide (Local
                                 Exchange Users Guide for Facility Based
                                 Providers). BellSouth shall work cooperatively
                                 with MCIm to ensure the accuracy of the data
                                 transfer by verifying it against the Master
                                 Street Address Guide (MSAG).

                                 6.2.1.3 The TN data is managed in ALI by the
                                 BellSouth, but the responsibility for providing
                                 the data resides with

                                                           Attachment VIII -- 80
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    each Local Service Provider.

                  6.2.2 DIRECTORY ASSISTANCE DATA INFORMATION EXCHANGES AND
                  INTERFACES

                           6.2.2.1 Subscriber List Information

                                    6.2.2.1.1 BellSouth shall provide to MCIm,
                                    when an industry standard is available, and
                                    upon request by MCIm, all published
                                    Subscriber List Information (including such
                                    information that resides in BellSouth's
                                    master subscriber system/accounts master
                                    file) via an electronic data transfer medium
                                    and in a format which is acceptable to MCIm,
                                    on the same terms and conditions and at the
                                    same rates that the BellSouth provides
                                    Subscriber List Information to itself or to
                                    other third parties. When industry standards
                                    are available, all changes to the Subscriber
                                    List Information shall be provided to MCIm
                                    on the same day as the change occurred
                                    through the electronic data transfer medium
                                    used to transmit the initial Subscriber List
                                    Information. Both the initial List and all
                                    subsequent Lists shall indicate for each
                                    subscriber whether the subscriber is
                                    classified as residence or business class of
                                    service.

                           6.2.2.2 This section addresses data format
                           requirements and data inclusion requirements for
                           directory assistance data information exchange
                           between BellSouth and MCIm. BellSouth shall provide
                           MCIm the following:

                                    6.2.2.2.1 List of NPA-NXX's relating to the
                                    listing records being provided.

                                    6.2.2.2.2 List of Directory Section names
                                    and their associated NPA-NXX's.

                                    6.2.2.2.3 List of Community Names expected
                                    to be associated with each of the NPA-NXX's
                                    for which listing records shall be provided.

                                    6.2.2.2.4 List of Independent Company names
                                    and their associated NPA-NXX's for which
                                    their listing data shall be included in
                                    BellSouth's listing data.

                                                           Attachment VIII -- 81
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                    6.2.2.2.5 List of Independent Company names
                                    and their associated NPA-NXXs for which
                                    their listing data is a part of BellSouth's
                                    directory database, but BellSouth is not to
                                    provide the listing data to MCIm under this
                                    request.

                                    6.2.2.2.6 Listing volume totals by directory
                                    section, NPA, and state.

                                    6.2.2.2.7 Average daily update volume by
                                    directory section, NPA, and state.

                                    6.2.2.2.8 Identify any area wide or
                                    universal service numbers which may be
                                    listed. Identify the telephone number to be
                                    provided to callers outside the servicing
                                    area.

                                    6.2.2.2.9 Identify any listing condition(s)
                                    unique to BellSouth's serving area which
                                    may require special handling in data
                                    processing in the directory. Indented
                                    Listings (Captions) should be identified and
                                    delivered handled as specified.

                            6.2.2.3 Considerations Relating to an Indented
                            Listing (Caption) Set Requirements

                                    6.2.2.3.1 Use of line numbers, or other
                                    methods, to ensure the integrity of the
                                    caption set and identify the sequence or
                                    placement of a listing record within the
                                    caption set. A sufficient range of numbers
                                    between listing records is required to allow
                                    for the expansion of the caption set. A
                                    method is also required to permit the
                                    caption header record to be identified, but
                                    each level of indent is not required to be
                                    recapped; placement of the indent is based
                                    on line number. This method does require
                                    stringent edits to ensure the integrity of
                                    the caption set.

                                    6.2.2.3.2 Use of guideline or recapped data
                                    to identify previously established header
                                    and sub-header records for placement of data
                                    within the caption set. This permits
                                    flexibility to easily expand the caption
                                    set. This method also requires that, in
                                    addition to the caption header record, each
                                    level of

                                                           Attachment VIII -- 82
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                            indent be recapped in order to properly build the
                            caption set.

                           6.2.2.3.3 In order to maintain the integrity of
                           caption replacement, with end-of-day cumulative
                           effect, one OUT record must be sent to delete the
                           entire caption set, followed by IN activity each
                           listing record within the caption set.

                           6.2.2.3.4 MCIm requires listing instruction codes on
                           the service order which indicate how the set is to
                           appear in the published directory.

                  6.2.2.4 Data Processing Requirements: BellSouth and
                  MCIm shall mutually agree to standards on the following data
                  processing requirements:

                            6.2.2.4.1 Identify type of tape to be used in
                            sending the test and initial load data. For example,
                            reel or cartridge tape. Due to the size of an
                            initial load, it would be generally expected to be
                            on tape and the daily update activity via another
                            media, such as NDM.

                            6.2.2.4.2 Identify tape or dataset label
                            requirements.

                            6.2.2.4.3 Identify tracking information
                            requirements. For example, use of header and trailer
                            records for tracking date and time, cycle numbers,
                            sending and receiving site codes, volume count for
                            the given tape/dataset. It may also be helpful to
                            have some filler fields for future use.

                            6.2.2.4.4 Identify dates MCIm should not expect to
                            receive daily update activity.

                            6.2.2.4.5 Data should be received in uppercase. An
                            asterisk (*) should be used advise of the need to
                            apply the reverse capitalization rule. However, if
                            the provider determines to provide the listing data
                            from a database that has already messaged the data
                            and applied the capitalization rules, the asterisk
                            may be omitted.

                            6.2.2.4.6 Identify information that shall enable
                            MCIm to identify listings within an indented list
                            (caption) set.

                                                           Attachment VIII -- 83
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                                            For example:

                                                     6.2.2.4.6.1 When a
                                                     particular listing has been
                                                     designated to be filed as
                                                     the first listing for a
                                                     given level (0-7) of indent
                                                     - usually out of alpha
                                                     sequence.

                                                     6.2.2.4.6.2 When an
                                                     alternate call listing
                                                     (e.g. If no answer) relates
                                                     to multiple preceding
                                                     listings of the same level.

                                            6.2.2.4.7 Identify any other
                                            pertinent information needed to
                                            properly process the data.

                                    6.2.2.5 Listing Types

LISTED                                      The listing information is available
                                            for all directory requirements.

NON-LISTED                                  The listing information is available
                                            to all directory requirements, but
                                            the information does not appear in
                                            the published street directory.

NON-PUBLISHED                               A directory service may confirm, by
                                            name and address, the presence of a
                                            listing, but the telephone number is
                                            not available. MCIm may confirm the
                                            address, but is not permitted to
                                            receive the non-published telephone
                                            number. The listing information is
                                            not available in either the
                                            published directory or directory
                                            assistance.

                                    6.2.2.6 Listing Styles

LISTING STYLE                       DESCRIPTION

STRAIGHT LINE                       All listing information is formatted in
                                    a straight line. Data generally consists of
                                    Name, Address, Community, and Telephone
                                    Number. Additional data may consist of
                                    dialing instructions or other general
                                    information relating to the listing.

                                                           Attachment VIII -- 84
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

INDENTED LISTING       Two or more listing records relating to the same listed
SET -                  subscriber. The first is formatted as a straight line
 STRAIGHT LINE         listing with the additional listing(s) indented one
UNDER                  degree under the straight line listing.
 (SLU)
INDENTED LISTING SET - Formatted with one listing header record and multiple
CAPTION SET below.     indented listing records. See detailed description below.

                         INDENTED LISTING (CAPTION) SET

HEADER RECORD          Contains listed name; address and
                       telephone number data fields are blank.

SUB-HEADER RECORD/     May contain name data only, or may include
LISTING                address and telephone number data.
                       Associated subordinate records may, or may
                       not be present.

INDENTED NAME          Contains name data , may or may not have
                       address LISTING data, and telephone number
                       data.

INDENTED ADDRESS       Contains address and telephone number data; the
LISTING                name data text field is blank.

LEVEL OF INDENT        Header record is zero (0),
                       sub-header and indented records range from 1 - 7.

                                                           Attachment VIII -- 85
<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

                  6.2.2.7 Data Field Elements

                           Requirements for Initial Processing and Daily Update
                           Activity
<TABLE>
<CAPTION>

DATA FIELD                  DATA ELEMENT      FIELD LENGTH

<S>      <C>                  <C>            <C>                               <C>
         ACTION CODE          A ' Add         I ' In                             Required: alpha
                              D ' Delete or   O ' out                            character


         RECORD              Sequentially assigned number to                     Required: 8 digits
         NUMBER              each record for a given process
                             (test, initial load, or update activity).
                             Number assignment begins with 00000001 and
                             is incremented by 1 for each record on the
                             file.

         NPA                 Area code relating to the directory                 Required: 3 digits
                             section the record is to be listed.

         COMPANY             The 4-character company code as                     Required: 4 digits
         IDENTIFIER          defined in Section 8 of the National
                             Exchange Carrier Association, Inc.
                             Tariff.

         DIRECTORY           Name of the directory section                       Required: Maximum of 50
         SECTION             where the record is to be listed.                   alpha characters
         LISTING             F ' Foreign                                         Optional 1 alpha
         IDENTIFIER          C' Cross-Reference                                  character
                             E' Enterprise (WX number requiring operator
                             assistance to connect the call)
                             W' Wide area or universal service

         FILE                B Business (4)                                      Required: Maximum of 3
         PLACEMENT           R Residence (1)                                     alpha characters
                             G Government (2) BR Business & Residence (5)
                             BG Business & Government (6) BRG Business,
                             Residence, & Government (7)

         LISTING TYPE        L'     Listed                                       Required: Maximum of 2
</TABLE>

                                                           Attachment VIII -- 86
<PAGE>

<TABLE>
<CAPTION>

           MCImetro - BellSouth Mississippi Interconnection Agreement

<S>                                <C>                                         <C>
                                    N/Non-Listed                                alpha characters
                                    NP/Non-Published

LISTING STYLE                       S/Straight line
                                    I/Indented listing set

                                    An Indented listing relates to either a
                                    caption or Straight Line Under (SLU) set
                                    listing.

INDENT LEVEL                        0/Non-indented record                       Required: 1 digit
                                    1 - 8/Level of indented record

ADDRESS                             For example: 123, A-123, 123-1/2            Optional: Maximum of 20
                                                                                alphanumeric characters,
                                                                                including hyphen, space,
                                                                                and slash

ADDRESS PRE-
DIRECTIONAL                         For example: N, S, E, W, NE, SW,            Optional: Maximum of 5
                                    NORTH                                       alpha characters

ADDRESS                             For example: Main Peachtree-                Optional: Maximum of 100
                                    Dunwoody, HWY 75 at Exit 30                 alpha, alphanumeric
                                                                                characters, including
                                                                                spaces and hyphens.

ADDRESS                             For example: SUITE 160, ST, or              Optional: Maximum of 20
SUFFIX OR                           WAY                                         numeric, alpha, or
THOROUGHFARE                                                                    alphanumeric characters


ADDRESS POST                        For example: N, S, NE, SW                   Optional: Maximum of 5
DIRECTION                                                                       alpha characters

ADDRESS ZIP                         5-digits or ZIP + 4                         Optional: Maximum of 10
CODE                                                                            digits, including the hyphen
                                                                                when using ZIP + 4

COMMUNITY                           Identifies the name of the                  Maximum of 50
NAME                                community associated with the               alphanumeric characters,
                                    listing record. See Glossary for            including spaces and
                                    more details.
</TABLE>

                                                           Attachment VIII -- 87
<PAGE>

<TABLE>
<CAPTION>
                  MCImetro - BellSouth Mississippi Interconnection Agreement

<S>                                <C>                                         <C>
STATE NAME                          Identifies the state associated with        Maximum of 2 alpha
ABBREVIATION                        the community name; 2-character             characters
                                    state abbreviation used by the US
                                    Postal Office.


INFORMATION                         Miscellaneous information relating          Optional: Maximum of 250
TEXT                                to the listing. Including, but not          alpha, numeric, or
                                    limited to, for example: TOLL FREE          alphanumeric characters
                                    DIAL 1 & THEN, CALL COLLECT,
                                    or TDD ONLY. The various types
                                    of Information Text must be
                                    identified to MCIm.

NAME - FIRST                        Surname of a Residence or                   Required for a zero (0) level
WORD                                Business listing, or first word of a        record.
                                    Business or Government Listing              Optional if an indented
                                                                                (level 1-8) record, unless
                                    Multi-word or hyphenated                    the name text present in the
                                    surnames should be treated as one           indented record relates to a
                                    word.                                       Surname.

                                                                                Maximum of 50 alpha,
                                                                                numeric, alphanumeric, or
                                                                                special characters

NAME -                              Given name and/or initial(s) of a           Expected if the First Word is
SUBSEQUENT                          Surname listing or Additional               the Surname of a
WORD(S)                             word(s) for a Business or                   Residence or Business
                                    Government listing                          listing. Maximum of 250
                                                                                alpha, numeric, special, or
                                                                                alphanumeric characters.

LINEAL DESCENT                      e.g. SR, JR, III. If Lineal Descent         Optional: Maximum 10
                                    data cannot be uniquely identified,         alpha characters
                                    it should be included with the Listed
                                    Name Subsequent Word(s) data
                                    and placed at the end of the name
                                    data.

TITLE(s)                            e.g. MRS, LT COL, RET SGR, DR.              Optional: Maximum of 20
                                    Multiple titles are acceptable. If          alpha charaters
                                    title data cannot be uniquely
                                    identified, it should be included with
                                    the Listed Name Subsequent
                                    Word(s) data and placed at the end
</TABLE>

                                                           Attachment VIII -- 88
<PAGE>

<TABLE>
<CAPTION>

           MCImetro - BellSouth Mississippi Interconnection Agreement
<S>                                <C>                                         <C>
                                    of the name data stream. If lineal descent
                                    is also in the Listed Name Subsequent
                                    Word(s) data field, title data should be
                                    placed following the lineal descent data.

DEGREE                               e.g. MD, CPA, PHD. Multiple                Optional: Maximum of 20
                                    degrees are acceptable. If degree           alpha characters
                                    data cannot be uniquely identified,
                                    it should be included with the Listed Name
                                    Subsequent Word(s) data and placed at the
                                    end of the name data stream. If lineal
                                    descent and/or title data is also present,
                                    it should follow title data.

NICKNAME                            Another name the listed subscriber          Optional:Maximum of 20
                                    may be known by.                            alpha characters.

BUSINESS                            Term used to identify the listed            Optional: Maximum of 50
DESIGNATION                         subscriber's profession, business,         including space and hyphen
                                    or location, e.g. ATTY, CARPETS,
                                       OFC

STANDARD                            NPA NXX-LINE                                Optional: 12 characters
TELEPHONE                                                                       including space and hyphen
NUMBER *

NON-STANDARD                        Telephone numbers less than or              Optional: Minimum of 1
TELEPHONE                           more than the standard telephone            digit, maximum of 22
NUMBER *                            number                                      characters, including
Transaction                                                                     spaces and hyphen
</TABLE>

*Either a Standard or Non-standard telephone is required for a zero level record
unless the record is a Cross-reference listing or an Indented Listing (caption)
Set record. A telephone number may, or may not be present on an Indented Listing
Set record for level(s) 0-7.

                                                           Attachment VIII -- 89
<PAGE>

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------
SUBCRIBER INFORMATION
---------------------------------------------------------------------------------------------------------------------------
                                                         REAL-TIME       REAL TIME         FREQUENCY/
                                      LONG-TERM          ACCESS TO       TRANSACTION       TIME                 INTERIM
BUSINESS FUNCTION                     SOLUTION*          DATA**          PROCESSING        INTERVAL             SOLUTION
---------------------------------------------------------------------------------------------------------------------------
<S>                                   <C>               <C>              <C>               <C>                  <C>
BellSouth provides all                Electronic            N              N/A             One-time only        To be
published Subscriber List             Interface -                                                               negotiated
Information                           within 30 days
                                      of Agreement
---------------------------------------------------------------------------------------------------------------------------
BellSouth provides MCIm with          Electronic            N              N/A             same day as          To be
changes to Subscriber List            Interface                                            changes occurs       negotiated
Information
---------------------------------------------------------------------------------------------------------------------------
BellSouth provides all Street         Electronic            N              N/A             One-time only        To be
Address Guide Information             Interface                                                                 negotiated
(SAG)
---------------------------------------------------------------------------------------------------------------------------
BellSouth provides changes            Electronic            N              N/A             same day as          To be
to Street Address Guide               Interface                                            changes occur        negotiated
Information (SAG)
---------------------------------------------------------------------------------------------------------------------------
</TABLE>

    *To be implemented by January 1, 1997, or agreed upon timeframe. All system
    availability is operational 24 hours a day, 7 days a week unless otherwise
    specified.
    **Real-Time access to real-time or most current available data, as opposed
    to real-time browsing of a database that may be outdated

<PAGE>

           MCImetro - BellSouth Mississippi Interconnection Agreement

<TABLE>
<CAPTION>
---------------------------------------------------------------------------------------------------------------------------
OTHER INFORMATION
---------------------------------------------------------------------------------------------------------------------------
                                                        REAL-TIME       REAL TIME            FREQUENCY/
                                      LONG-TERM         ACCESS TO       TRANSACTION          TIME               INTERIM
BUSINESS FUNCTION                     SOLUTION*         DATA**          PROCESSING           INTERVAL           SOLUTION
---------------------------------------------------------------------------------------------------------------------------
<S>                                   <C>              <C>              <C>                  <C>                <C>
BellSouth provides MCIm                Electronic                                                               To be
PICs available at a central            Interface                             N/A                                negotiated
office level
---------------------------------------------------------------------------------------------------------------------------
MCIm view subscriber profile           Electronic          Y                 N/A                N/A             To be
information at the line and            Interface                                                                negotiated
trunk level.
---------------------------------------------------------------------------------------------------------------------------
MCIm views all features and            Electronic          Y                 N/A                N/A             To be
services, including new                Interface                                                                negotiated
services, trial offers and
promotions available through
BellSouth
---------------------------------------------------------------------------------------------------------------------------
MCIm views all services and            Electronic         Y                 N/A                 N/A             To be
features technically available         Interface                                                                negotiated
from each switch the BellSouth
may use to provide a Local
Switching element.
---------------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

<TABLE>
<CAPTION>
           MCImetro - BellSouth Mississippi Interconnection Agreement

------------------------------------------------------------------------------------------------------------------------
TELEPHONE NUMBER
RESERVATIONS
------------------------------------------------------------------------------------------------------------------------
                                                         REAL-TIME        REAL TIME         FREQUENCY/
                                      LONG-TERM          ACCESS TO        TRANSACTION       TIME             INTERIM
BUSINESS FUNCTION                     SOLUTION*          DATA**           PROCESSING        INTERVAL         SOLUTION
------------------------------------------------------------------------------------------------------------------------
<S>                                   <C>               <C>               <C>               <C>              <C>
MCIm views available list of           Electronic          Y                   N/A             N/A            To be
telephone numbers                      Interface                                                              negotiated
------------------------------------------------------------------------------------------------------------------------
MCIm reserves/assigns                  Electronic          Y                   Y               N/A            To be
telephone numbers for                  Interface                                                              negotiated
both simple and complex
services from available
BellSouth list/number
services system
------------------------------------------------------------------------------------------------------------------------
BellSouth provides                     Electronic          Y                  Y                N/A            To be
confirmation of simple number          Interface                                                              negotiated
reservation
------------------------------------------------------------------------------------------------------------------------
BellSouth provides                     Electronic          N                  N              within 24        To be
confirmation of complex                Interface                                               hours          negotiated
number reservation
------------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

<TABLE>
<CAPTION>
           MCImetro - BellSouth Mississippi Interconnection Agreement

--------------------------------------------------------------------------------------------------------------------------
ORDER SUBMISSION
--------------------------------------------------------------------------------------------------------------------------
                                                         REAL-TIME          REAL TIME       FREQUENCY/
                                      LONG-TERM          ACCESS TO          TRANSACTION     TIME               INTERIM
BUSINESS FUNCTION                     SOLUTION*          DATA**             PROCESSING      INTERVAL           SOLUTION
--------------------------------------------------------------------------------------------------------------------------
<S>                                   <C>               <C>                 <C>             <C>                <C>
MCIm submits order for desired        Electronic            Y                    Y              N/A            To be
resold features and services,         Interface                                                                negotiated
Local Services, unbundled
elements and/or combinations
of elements from BellSouth
--------------------------------------------------------------------------------------------------------------------------
MCIm orders local, intraLATA,         Electronic            Y                    Y              N/A            To be
InterLATA, and international          Interface                                                                negotiated
service on a single order
--------------------------------------------------------------------------------------------------------------------------
  MCIm requests suspension,           Electronic            Y                    Y              N/A            To be
  termination or restoration of       Interface                                                                negotiated
  service
--------------------------------------------------------------------------------------------------------------------------
  MCIm adjusts pending order          Electronic            Y                    Y              N/A            To be
       due dates                      Interface                                                                negotiated
--------------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------
Order Tracking
-----------------------------------------------------------------------------------------------------------------------
                                                Real-Time       Real-Time
                                Long-Term       Access To       Transaction     Frequency/           Interim
Business Function               Solution*       Data**          Processing      Time Interval        Solution
-----------------------------------------------------------------------------------------------------------------------
<S>                             <C>             <C>             <C>             <C>                  <C>
BellSouth provides              Electronic         Y               Y            within 1 hour         To be
acknowledgment or               Interface                                                             negotiated
rejection of Service
Orders to MCIm
-----------------------------------------------------------------------------------------------------------------------
BellSouth provides              Electronic         Y               Y               N/A                To be
errors in Service               Interface                                                             negotiated
Orders to MCIm
-----------------------------------------------------------------------------------------------------------------------
BellSouth provides              Electronic         N               Y           within 4 hours         To be
FOC to MCIm                     Interface                                                             negotiated
-----------------------------------------------------------------------------------------------------------------------
Provisioning
-----------------------------------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------------------------------
BellSouth provides              Electronic         Y               Y               N/A                To be
delay notification              Interface                                                             negotiated
to MCIm
-----------------------------------------------------------------------------------------------------------------------
BellSouth provides              Electronic         Y               Y            within 1 hour         To be
completion notification         Interface                                                             negotiated
to MCIm
-----------------------------------------------------------------------------------------------------------------------
MCIm schedules service          Electronic         Y               Y               N/A                To be
installations                   Interface                                                             negotiated
-----------------------------------------------------------------------------------------------------------------------
BellSouth provides              Electronic         Y               Y               N/A            BellSouth's LCSC
charges on special              Interface                                                         will immediately
construction to MCIm                                                                              notify MCIm by phone
-----------------------------------------------------------------------------------------------------------------------
BellSouth supplies MCIm         Electronic         Y               N               N/A                To be
with Due Date Interval          Interface                                                             negotiated
Guides/Job Aids
-----------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>

                      MCImetro - BellSouth Mississippi Interconnection Agreement


MCIm Comment
This exhibit specifies, for each information exchange between MCIm and
BellSouth, the type of interface, whether real-time access and processing is
required, and the frequency of information exchanges, this information is
required to ensure that both parties are in agreement on each others' interface
requirements.



<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                               TABLE OF CONTENTS

                                 ATTACHMENT IX
                             SECURITY REQUIREMENTS

Section 1       Physical Security               IX - 1

Section 2       Network Security                IX - 2

Section 3       Revenue Protection              IX - 3

Section 4       Law Enforcement Interface       IX - 3

                                                                 ATTACHMENT IX-i
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

                                 ATTACHMENT IX

                             SECURITY REQUIREMENTS

SECTION 1. PHYSICAL SECURITY

BellSouth shall exercise the same level of care it provides itself to prevent
harm or damage to MCIm or its employees, agents or subscribers, or their
property. BellSouth agrees to take reasonable and prudent steps to ensure the
adequate protection of MCIm property located within BellSouth premises,
including but not limited to:

         1.1 Restricting access to MCIm equipment, support equipment, systems,
         tools, or spaces which contain or house MCIm equipment enclosures to
         MCIm employees and other authorized non-MCIm personnel to the extent
         necessary to perform their specific job function.

         1.2 Furnishing to MCIm a current written list of BellSouth's employees
         which BellSouth authorizes to enter spaces which house or contain MCIm
         equipment or equipment enclosures, including caged areas, authorized
         with current facsimiles of the types of identifying credentials to be
         carried by such persons.

         1.3 Complying at all times with security and safety procedures and
         requirements mutually agreed upon at the first collocation meeting for
         each site, including but not limited to sign-in, identification, and
         escort requirements while in spaces which house or contain MCIm
         equipment or equipment enclosures..

         1.4 Assuring that the physical security and the means of ingress and
         admission to space that house MCIm equipment or equipment enclosures
         are equal to or exceed those provided for BellSouth pursuant to
         BellSouth Admissions Practices.

         1.5 Allowing MCIm to inspect or observe spaces which house or contain
         MCIm equipment or equipment enclosures at any time and to furnish MCIm
         with all keys, entry codes, lock combinations, or other materials or
         information which may be needed to gain entry into any secured MCIm
         space.

         1.6 Where BellSouth has access device systems, agreeing to coordinate
         MCIm's use of any access device systems, whether biometric or card
         reader, or types which are encoded identically or mechanical coded
         locks on external

                                                               ATTACHMENT IX - 1
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

         and or internal doors to spaces which house MCIm equipment.

         1.7 Limiting the keys or other access methods used in its systems for
         spaces which contain or house MCIm equipment or equipment enclosures to
         BellSouth employees and representatives to emergency access only. MCIm
         shall further have the right to change locks or other access methods on
         all spaces where deemed necessary for the protection and security of
         such spaces. In such an event, MCIm shall provide BellSouth with
         replacement keys or equivalent.

         1.8 Ensuring that doors that provide access to MCIm equipment
         enclosures are equipped to protect against removal of hinge pins.

         1.9 Controlling unauthorized access from passenger and freight
         elevators by continuous surveillance or by installing security
         partitions, security grills, locked gates or doors between elevator
         lobbies and spaces which contain or house MCIm equipment or equipment
         enclosures, as selected by MCIm and at MCIm's expense.

         1.10 Providing prompt notification to designated MCIm personnel
         whenever BellSouth has determined that there has been an actual or
         attempted security breach. MCIm shall provide prompt notice to
         BellSouth when MCIm determines that an actual or attempted security
         breach of the MCIm secured space has occurred.

         1.11 Ensuring that areas designated to house MCIm equipment are
         environmentally appropriate for the MCIm equipment installation, and,
         consistent with Attachment V, adequate to maintain proper operating
         conditions for the MCIm equipment.

SECTION 2. NETWORK SECURITY

         2.1 MCIm's secured space shall be covered by the same back-up and
         recovery plan used for BellSouth space in the event of a system failure
         or emergency.

         2.2 BellSouth shall install controls and logical security as set forth
         in Attachment V, Section 2.17.4, to (i) disconnect a user for a
         pre-determined period of inactivity on authorized ports; (ii) protect
         subscriber proprietary information; (iii) ensure both ongoing
         operational and update integrity, (iv) assure that all approved system
         and modem access be secured through security servers and that access to
         or connection with a network element shall be established through a
         secure network or security gateway; and (v) provide security equal to
         or better than that which BellSouth provides to itself (which shall
         include Design, Development, Maintenance and Administration

                                                               ATTACHMENT IX - 2
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

         Security Standards for Network Elements, Network Element Support
         Systems, and other Computer Systems).

         2.3 BellSouth shall provide Network Security (i) ensuring that all
         MCIm-approved systems and modem access are secured through
         MCIm-approved security devices; and (ii) ensuring that access to or
         connection with a network element are established through MCIm
         security-approved networks or gateways.

         2.4 BellSouth agrees to comply with MCIm Corporate Security Standards,
         including but not limited to "MCIm Information Asset Security
         Standards", February, 1996, Document Number 076-0004-01-01.OF-ER and
         "MCIm Minimum Security Baseline Standard for Information Systems",
         January 1996, Document Number 076-0003-01.OF-ER.

SECTION 3. REVENUE PROTECTION

         3.1 BellSouth shall make available to MCIm all present and future fraud
         prevention or revenue protection features, including prevention,
         detection, or control functionality embedded within any of the Network
         Elements. These features include, but are not limited to screening
         codes, information digits assigned such as code 07 which indicate
         special handling of the call is required, call blocking of domestic,
         international, 800, 888, 900, NPA-976 numbers. If and when BellSouth
         can provide information digits `29' and `70' to itself, BellSouth
         must provide them to MCIm.

            3.1.1 Uncollectible or unbillable revenues resulting from, but not
            confined to provisioning, maintenance, or signal network routing
            errors shall be the responsibility of the party causing such error,
            and such liability shall be calculated pursuant to the methodology
            set forth in Attachment VIII, section 4.1.4.

            3.1.2 Uncollectible or unbillable revenues resulting from the
            accidental or malicious alteration of software underlying Network
            Elements or their subtending operational support systems by
            unauthorized third Parties shall be the responsibility of the Party
            having administrative control of access to said Network Element or
            operational support system software to the extent such unbillable or
            uncollectible revenue results from the negligent or willful act or
            omission of the Party having such administrative control.

            3.1.3 BellSouth shall be responsible for any uncollectible or
            unbillable revenues resulting from the unauthorized physical
            attachment to loop facilities from the Main Distribution Frame up to
            and including the Network Interface Device, including clip-on fraud
            to the extent such

                                                               ATTACHMENT IX - 3
<PAGE>

             MCIm - BellSouth Mississippi Interconnection Agreement

            unbillable or uncollectible revenue results from the negligent or
            willful act or omission of BellSouth. BellSouth shall provide soft
            dial tone to allow only the completion of calls to final termination
            points required by law.

SECTION 4. LAW ENFORCEMENT INTERFACE

Upon request by MCIm Security/Network Services, BellSouth shall provide all
necessary assistance to facilitate the execution of a wiretap, call trace or
dialed number recorder court order provided from law enforcement authorities. In
that regard, BellSouth shall provide seven day a week / twenty-four hour a day
installation and information retrieval pertaining to traps, assistance involving
emergency traces and information retrieval on subscriber invoked CLASS services.

                                                               ATTACHMENT IX - 4