Note:  Confidential Treatment Requested.  Confidential portions of this document
have been redacted and have been separately filed with the Commission.

                                    AGREEMENT

         This Agreement  ("Agreement") is made and entered into as of this 9 day
of May 2000,  by and  between  Level 3  Communications,  LLC a Delaware  limited
liability  company  ("Level  3")  and  Teligent   Services,   Inc.,  a  Delaware
corporation ("Teligent").

                                    RECITALS

A.  Level 3 intends to construct and/or is currently  constructing multi-conduit
fiber optic communications systems in various metropolitan areas.

B.  Teligent  desires to obtain the right to use  [REDACTED]  fibers  within the
Level  3  installed  fiber  optic  communications   system  in  certain  of  the
metropolitan  areas in which Level 3 is installing  them, and Level 3 desires to
grant Teligent a license to use such fibers.

C. Level 3 intends to construct  and/or is currently  constructing  a nationwide
multi-conduit fiber optic communications network which will, among other things,
connect  the  metropolitan  multi-conduit  fiber  optic  communications  systems
described above.

D.  Teligent  desires to obtain  the right to use  certain  Level 3  wavelengths
capacity between and connecting such metropolitan  areas, and Level 3 desires to
grant Teligent a right to use such wavelengths capacity.

E. Level 3 owns,  controls or holds  lease-hold  interests in certain office and
storage  space  suitable  for the  placement  and  operation  of  communications
equipment which Teligent  desires the right to occupy for collocation  purposes;
Level 3 is  willing  to grant  Teligent  the  right to occupy  portions  of such
facilities.

F.  Level 3 and  Teligent  intend  to  agree  upon the  terms  of a  non-binding
memoranda of  understanding  respecting the purchase by Teligent from Level 3 of
dark fiber,  roof rights and certain  voice,  private  line and  peering/transit
services,  and the purchase by Level 3 of certain  international  services  from
Teligent.  In  addition,  the parties may explore  joint  marketing  and product
development as set forth in the non-binding Memorandum of Understanding.

                                   ARTICLE 1.
                              TERMS AND CONDITIONS

1.01 Level 3 agrees to provide and  Teligent  agrees to purchase  from Level 3 a
license to use Level 3 fiber on and in accordance  with the terms and conditions
as are set forth in Exhibit "1" hereto.
<PAGE>
1.02 Level 3 agrees to provide and Teligent  agrees to purchase from Level 3 the
right to use Level 3 wavelengths  capacity on and in  accordance  with the terms
and conditions as are set forth in Exhibit "2" hereto.

1.03 Level 3 agrees to provide  and  Teligent  agrees to  license  from Level 3
collocation  space in accordance  with the terms and conditions as are set forth
in Exhibit "3" hereto.

1.04 The non-binding Memorandum of Understanding is attached as Exhibit "4"
hereto.

                                   ARTICLE 2.
                  COMMON TERMS AND CONDITIONS BETWEEN EXHIBITS

2.01  Notwithstanding  any  conflicting  terms or  conditions  contained  in the
Exhibits  attached  hereto,  unless the  contrary is  specifically  stated,  the
following  terms and  conditions  shall apply with respect to the subject matter
thereof  with  respect to all  services  provided  by Level 3 and  purchased  by
Teligent hereunder. As used herein, the term "Agreement" includes this agreement
and all Exhibits attached hereto, except for Exhibit 4.

2.02  "Affiliate"  shall mean,  with  respect to a party,  any other entity that
directly  or  indirectly,  through  one or  more  intermediaries,  controls,  is
controlled  by,  or  is  under  common  control  with,  such  party  ("control,"
"controlled  by" and "under  common  control  with"  shall mean the  possession,
directly or  indirectly,  of the power to direct or cause the  direction  of the
management  and  policies  of a  party,  whether  through  ownership  of  voting
securities,  by  contract  or credit  arrangement,  as trustee or  executor,  or
otherwise).

                                   ARTICLE 3.
                                   ASSIGNMENT

3.01  This  Agreement  shall be  binding  upon and inure to the  benefit  of the
Parties hereto and their  respective,  permitted (as provided below)  successors
and assigns.  Except as permitted herein or as specifically permitted in Section
17 of Exhibit 1, neither party may assign,  encumber or otherwise  transfer this
Agreement  or any of its Exhibits to any other party  without the prior  written
consent  of the other  party,  such  consent  not to be  unreasonably  withheld,
provided  that either party shall have the right,  without  consent of the other
party,  but with  written  notice to such other  party,  to assign or  otherwise
transfer  this  Agreement  (so long as the  same  does  not  interfere  with the
location  of  or  provisioning  of  any  service):  (i)  as  collateral  to  any
institutional  lender of the  assigning  party  subject to the prior  rights and
obligations  of the parties  hereunder;  and (ii) to any parent,  subsidiary  or
Affiliate of the assigning  party, or to any entity into which such party may be
merged or consolidated or which purchases all or substantially all of the assets
or stock of such party.  Any assignee or transferee shall continue to be subject
to all of the provisions of this Agreement including its Exhibits,  (except that
any lender referred to in clause (i) above shall not incur any obligations under
this  Agreement  nor  shall  it be  restricted  from  exercising  any  right  of
enforcement  or  foreclosure  with respect to any related  security  interest or
lien, so long as the purchaser in  foreclosure  is subject to the  provisions of
this Agreement).
<PAGE>
3.02 This Agreement and each of the parties'  respective  rights and obligations
under this Agreement shall be binding upon and shall inure to the benefit of the
parties hereto and each of their respective permitted successors and assigns.

3.02 Nothing  contained in this Article shall be deemed or construed to prohibit
Level 3 from selling,  transferring,  leasing, licensing,  granting indefeasible
rights of use or entering  into similar  agreements or  arrangements  with other
parties.

                                   ARTICLE 4.
                                 CONFIDENTIALITY

4.01  (a) As used  herein,  "Proprietary  Information"  shall  mean  information
disclosed, both orally and in writing, concerning the business of the disclosing
party  and/or the  businesses  of  current or  potential  third  party  vendors,
suppliers,  consultants,  contractors  and/or customers of the disclosing party,
including,  without limitation,  customer lists,  customer  addresses,  services
provided to specific  customers,  traffic and sales volumes,  customer  pricing,
equipment specifications, locations and use, network configurations,  capacities
and  capabilities,   current  or  prospective   relationship  with  vendors  and
independent  contractors (including,  without limitation,  information regarding
the  types  of  services  contracted  for and the cost of such  services  to the
disclosing  party),  implementation of technology,  data and programs,  finance,
sales,  marketing,  and development of telecommunication  and related technology
and services.  Such  information,  in whole or in part,  together with analyses,
compilations, programs, reports, proposals, studies, or any other documentation,
prepared by the disclosing  party or the other party,  as the case may be, which
contain or otherwise reflect or make reference to such  information,  whether or
not specifically marked as confidential by the Disclosing Party, are hereinafter
referred to as "Proprietary Information."
<PAGE>
(b) Level 3 and  Teligent  agree that if either  party  provides the other party
Proprietary   Information,   such  Proprietary  Information  shall  be  held  in
confidence,  and the receiving party shall afford such  Proprietary  Information
the same care and protection as it affords its own  confidential and proprietary
information  (which in any case shall be not less than reasonable care) in order
to avoid  disclosure  to or  unauthorized  use by any third  party.  The parties
acknowledge  and agree that all  information  disclosed  by either  party to the
other in  connection  with or pursuant to this  Agreement  shall be deemed to be
Proprietary Information,  provided that verbal information is indicated as being
confidential  or proprietary  when given.  All Proprietary  Information,  unless
otherwise  specified in writing,  shall  remain the  property of the  disclosing
party,  shall be used by the receiving party only for the intended purpose,  and
such written  Proprietary  Information,  including all copies thereof,  shall be
returned to the disclosing party or destroyed upon the request of the disclosing
party.  Proprietary  Information  shall not be  reproduced  except to the extent
necessary  to  accomplish  the  purpose  and  intent  of this  Agreement,  or as
otherwise may be permitted in writing by the disclosing party.

4.02 The foregoing provisions of Section 4.01 shall not apply to any Proprietary
Information  which  (i)  becomes  publicly  available  other  than  through  the
disclosing party; (ii) is required to be disclosed by a governmental or judicial
law,  order,  rule  or  regulation;  (iii)  is  independently  developed  by the
receiving  party;  or (iv) becomes  available  to the  receiving  party  without
restriction from a third party.

4.03   Notwithstanding   Sections  4.01  and  4.02  either  party  may  disclose
Proprietary Information to its employees,  agents, lenders, funding partners and
legal  and  financial   advisors  and  providers  to  the  extent  necessary  or
appropriate  in  connection  with the  negotiation  and/or  performance  of this
Agreement or in obtaining  financing,  provided that each such party is notified
of the confidential and proprietary  nature of such Proprietary  Information and
is  subject  to or agrees  to be bound by  similar  restrictions  on its use and
disclosure.

4.04 Upon execution of this Agreement, the parties shall mutually agree on press
announcements and releases,  by both parties,  announcing this Agreement and the
relationship  between  them.  The parties shall use good faith efforts to, on or
before May 9, 2000: i) agree upon the provisions of such press release;  and ii)
agree upon the information  which may be disclosed by the parties in response to
questions  raised as a result of any such press release.  The parties agree that
Teligent's  press  release  may  state  that  Teligent  is a Level 3  Strategic,
Preferred  Provider of fixed,  terrestrial,  high frequency,  wireless services.
Thereafter,  each party shall be permitted to discuss the general  nature of the
Agreement and  relationship  publicly in accordance with this Section 4 provided
that such discussions are consistent with and limited to matters  disclosed in a
previously approved press release.

4.05 In the event either party shall be required by law,  rule or  regulation to
disclose all or any part of this Agreement in, or attach all or any part of this
Agreement  to any  regulatory  filing or  statement,  each party  agrees that in
advance of such disclosure (unless compelled  otherwise by law) it shall discuss
and work cooperatively,  in good faith, with the other party, to protect, to the
extent possible, those items or matters which the other party deems confidential
and which may, in accordance with applicable laws, be deleted therefrom.

4.06 The provisions of this Article shall survive expiration or termination of
this Agreement.
<PAGE>
                                   ARTICLE 5.
                            CONTACT / ESCALATION LIST

         Within 90 days of the  execution of this  Agreement,  the Parties shall
supply each other with appropriate  network  contacts,  including  names,  phone
numbers,  beeper or cell-phone  numbers,  etc., as well as a problem  escalation
contact list and trouble reporting protocols and procedures for provisioning and
for  notifications  related to trouble  tickets  and  routine,  non-routine  and
emergency maintenance.
                                   ARTICLE 6.
                                     NOTICES

         All notices or other  communications  which are  required or  permitted
herein  shall be in writing and  sufficient  if  delivered  personally,  sent by
facsimile transmission followed by another form of written notification which is
capable of providing proof of delivery,  sent by prepaid  overnight air courier,
or sent by  registered  or  certified  mail,  postage  prepaid,  return  receipt
requested, addressed as follows:

         IF TO LEVEL 3:
                                    Level 3 Communications, LLC
                                    1025 Eldorado Blvd.
                                    Broomfield, CO 80021
                                    Attn: VP, Transmission and Special Services
                                    Fax: 720-569-1151

                           with copies to:
                                    Level 3 Communications, LLC
                                    1025 Eldorado Blvd.
                                    Broomfield, CO 80021
                                    Attn: VP, Network Operation
                                    Fax: 720-888-5228

                           and
                                    Level 3 Communications, LLC
                                    1025 Eldorado Blvd.
                                    Broomfield, CO 80021
                                    Attn: General Counsel
                                    Fax: 720-888-5128
<PAGE>
IF TO TELIGENT:            Teligent Services, Inc.
                                    8065 Leesburg Pike, Suite 400
                                    Vienna, VA  22182
                                    Attn: Chief Technology Officer
                                    Fax: 703-762-5349

                           with copies to:
                                    Teligent Services, Inc.
                                    8065 Leesburg Pike, Suite 400
                                    Vienna, VA  22182
                                    Attn:  VP of Network Planning/Engineering
                                    Fax: 703-762-5187

                           and
                                    Teligent Services, Inc.
                                    8065 Leesburg Pike, Suite 400
                                    Vienna, VA  22182
                                    Attn:  General Counsel
                                    Fax: 703-762-5227

or at such  other  address  as the party to whom  notice is to be given may have
furnished  to the  other  party in  writing  in  accordance  herewith.  Any such
communication  shall be deemed to have been given when  delivered  if  delivered
personally, on the same day as facsimile transmission (or the first business day
thereafter if faxed on a Saturday, Sunday or legal holiday), on the business day
after  dispatch if sent by overnight air courier,  or on the third  business day
after posting if sent by mail.

                                   ARTICLE 7.
                           ENTIRE AGREEMENT; AMENDMENT

         This  Agreement   constitutes   the  entire  and  final  agreement  and
understanding  between the parties with respect to the subject matter hereof and
supersedes all prior agreements relating to the subject matter hereof, which are
of no further force or effect including the nondisclosure  agreement between the
parties dated September  29,1998.  The Exhibits  referred to herein are integral
parts hereof and are hereby made a part of this  Agreement.  This  Agreement may
only be modified or supplemented by an instrument in writing  executed by a duly
authorized representative of each party.
<PAGE>
                                   ARTICLE 8.
                           RELATIONSHIP OF THE PARTIES

         The  relationship  between  Level 3 and  Teligent  shall not be that of
partners,  agents, or joint venturers for one another,  and nothing contained in
this  Agreement or its Exhibits  shall be deemed to constitute a partnership  or
agency  agreement  between them for any  purposes,  including but not limited to
federal income tax purposes.

                                   ARTICLE 9.
                                  COUNTERPARTS

         This  Agreement  may be  executed in one or more  counterparts,  all of
which taken together shall constitute one and the same instrument.

                                   ARTICLE 10.
                  CONSTRUCTION AND INTERPRETATION OF AGREEMENT

         The language in all parts of this  Agreement and its Exhibits  shall in
all  cases be  construed  simply,  as a whole  and in  accordance  with its fair
meaning  and  not  strictly  for  or  against  any  party.  The  parties  hereto
acknowledge  and agree that this Agreement and its Exhibits have been negotiated
by the parties and been the subject of arm's length and careful negotiation over
a considerable period of time, that each party has been given the opportunity to
independently  review this  Agreement and its Exhibits with legal  counsel,  and
that each party has the requisite  experience and  sophistication to understand,
interpret  and  agree  to the  particular  language  of the  provisions  hereof.
Accordingly,  in  the  event  of  an  ambiguity  in  or  dispute  regarding  the
interpretation of this Agreement including its Exhibits,  this Agreement and its
Exhibits shall not be interpreted or construed against either party.

                                   ARTICLE 11.
                                   ENFORCEMENT

         If any provision of this Agreement or any of its Exhibits, the deletion
of which  would not  adversely  affect the  receipt of any  material  benefit by
either party hereunder, shall be held by a court of competent jurisdiction to be
invalid or unenforceable,  the remainder of this Agreement shall not be affected
thereby and each other term and provision of this  Agreement  shall be valid and
enforceable to the fullest  extent  permitted by law. It is the intention of the
parties to this  Agreement,  and the parties hereto agree,  that in lieu of each
clause or provision of this  Agreement or its Exhibits that is illegal,  invalid
or  unenforceable,  the  court  shall  supply  as a part  of this  Agreement  an
enforceable  clause or provision as similar in term to such illegal,  invalid or
unenforceable clause or provision as may be possible.
<PAGE>
                                   ARTICLE 12.
                                  FORCE MAJEURE

Except as may  otherwise  be  specifically  provided in this  Agreement  or its
Exhibits,  neither  party shall be in default of this  Agreement  or any Exhibit
hereof [REDACTED] if and to the extent that any failure or delay in such party's
performance  is caused by any of the following  conditions and is not the result
of the  negligence or willful  misconduct of the affected party and such party's
performance  shall be excused and extended for and during the period of any such
delay: act of God; fire;  flood;  shortages or  unavailability or other delay in
delivery not  resulting  from the  responsible  party's  failure to timely place
accurate  orders  therefore;  lack of or delay in  transportation  or  capacity;
government codes, ordinances,  laws, rules, regulations or restrictions;  war or
civil  disorder;  failure of a third party to  recognize a right or right of way
required  to deliver  any  service;  or any other  cause  beyond the  reasonable
control of a party.  A force majeure event may not be claimed by either party to
alleviate  an  obligation  of that party to make payment due  hereunder.  In the
event of a delay or failure of performance  under this section as respects Level
3's delivery of service which Level 3 reasonably  believes will last longer that
fourteen (14) days,  Level 3 shall, as soon as is reasonably  practicable,  give
written  notice of the same to Teligent  specifying  the nature and  anticipated
duration of the Force  Majeure  Event and outline its recovery plan with respect
to the Force Majeure Event,  including the anticipated time in which to complete
the same. [REDACTED]

                                   ARTICLE 13.
                                 INDEMNIFICATION

13.01 Subject to the provisions of Article 14 of this Agreement,  Level 3 hereby
agrees  to  indemnify,  defend,  protect  and  hold  harmless  Teligent  and its
employees,  officers and directors, from and against, and assumes liability for:
(i) any claims,  causes of action or suits, and/or any injury, loss or damage to
any person,  tangible property or facilities of any person (including reasonable
attorneys'  fees and costs) to the extent  arising out of or resulting  from the
negligence or willful misconduct of Level 3, its officers, directors, employees,
servants,  affiliates,  agents,  contractors,  licensees,  invitees  and vendors
arising  out  of or in  connection  with  the  performance  by  Level  3 of  its
obligations  under this Agreement  including its Exhibits;  and (ii) any claims,
causes of action or suits,  and/or any liabilities or damages arising out of any
violation  by Level 3 of any  regulation,  rule,  statute or court  order of any
governmental  authority in  connection  with the  performance  by Level 3 of its
obligations under this Agreement including its Exhibits.
<PAGE>
13.02 Subject to the provisions of Article 14 of this Agreement, Teligent hereby
agrees  to  indemnify,  defend,  protect  and  hold  harmless  Level  3, and its
employees,  officers and directors, from and against, and assumes liability for:
(i) any claims,  causes of action or suits, and/or any injury, loss or damage to
any person,  tangible property or facilities of any person (including reasonable
attorneys'  fees and costs) to the extent  arising out of or resulting  from the
negligence  or  willful  misconduct  of  Teligent,   its  officers,   directors,
employees, servants,  affiliates,  agents, contractors,  licensees, invitees and
vendors  arising out of or in  connection  with the  exercise by Teligent of its
rights under this Agreement including its Exhibits;  and (ii) any claims, causes
of action  or suits,  and/or  any  liabilities  or  damages  arising  out of any
violation  by Teligent of any  regulation,  rule,  statute or court order of any
governmental authority in connection with the exercise by Teligent of its rights
under this Agreement including its Exhibits.

13.03 Level 3 and Teligent both agree that they will protect,  indemnify, defend
and hold the other party hereto harmless from any action brought by that parties
end users  against  the other  party  hereto  relating to or arising out of this
Agreement.

13.04 Level 3 and Teligent  agree to promptly  provide each other with notice of
any claim  which may  result in an  indemnification  obligation  hereunder.  The
indemnifying  party may  defend  such claim  with  counsel  of its own  choosing
provided  that no settlement or compromise of any such claim shall occur without
the consent of the  indemnified  party,  which consent shall not be unreasonably
withheld or delayed.

13.05  Level  3 and  Teligent  each  expressly  recognize  and  agree  that  its
obligation to indemnify,  defend,  protect and save the other  harmless is not a
material obligation to the continuing  performance of its other obligations,  if
any,  hereunder.  In the  event  that a party  shall  fail for any  reason to so
indemnify, defend, protect and save the other harmless, the injured party hereby
expressly  recognizes  that its sole  remedy in such event shall be the right to
bring legal  proceedings  against the other party for its damages as a result of
the other party's said failure to indemnify,  defend, protect and save harmless.
These  obligations shall survive the expiration or termination of this Agreement
and any of its Exhibits.

                                   ARTICLE 14.
                             LIMITATION OF LIABILITY

NOTWITHSTANDING  ANYTHING  TO THE  CONTRARY IN THIS  AGREEMENT  OR IN ANY OF THE
EXHIBITS,  IN NO EVENT SHALL EITHER  PARTY BE LIABLE TO THE OTHER FOR  INDIRECT,
INCIDENTAL,  CONSEQUENTIAL, SPECIAL, PUNITIVE OR EXEMPLARY DAMAGES, EVEN IF THAT
PARTY HAS BEEN  ADVISED OF THE  POSSIBILITY  OF SUCH  DAMAGES  ARISING  FROM ANY
PROVISION OF THIS AGREEMENT, SUCH AS, BUT NOT LIMITED TO, LOSS OF USE, INCOME OR
PROFITS, OR ANTICIPATED PROFITS OR LOST BUSINESS.

Nothing  contained  herein shall  operate as a limitation on the right of either
party hereto to bring an action for damages  against any third party,  including
claims for  indirect,  special or  consequential  damages,  based on any acts or
omissions of such third party.
<PAGE>
                                   ARTICLE 15
                                     WAIVER

The failure of either  party to insist  upon the  performance  of any  provision
herein or to exercise any right or privilege granted to it hereunder,  shall not
be construed as a waiver of such  provision or any  provisions  herein,  and the
same shall  continue in full force.  The various rights and remedies given to or
reserved by either party herein or allowed by law, shall be  cumulative,  and no
delay or omission to exercise  any of its rights  shall be construed as a waiver
of any  default  or  acquiescence,  nor  shall any  waiver of any  breach of any
provision be considered a condonement or any continuing or subsequent  breach of
the same provision.

                                   ARTICLE 16
                                  GOVERNING LAW

This Agreement  shall be governed by and interpreted in accordance with the laws
of the State of [REDACTED].

                                   ARTICLE 17
                                 REPRESENTATIONS

17.01 Each party to this  Agreement  represents  and warrants to the other party
that: (a) such party has the full corporate right,  power and authority to enter
into this  Agreement and to perform all acts  required of it hereunder;  (b) the
execution of this Agreement by such party,  and the performance by such party of
its obligations and duties hereunder,  do not and will not violate any agreement
to which  such  party is a party or by  which it is  otherwise  bound;  (c) when
executed and delivered by such party,  this Agreement will constitute the legal,
valid and binding  obligation of such party,  enforceable  against such party in
accordance  with the  terms  and  conditions  of this  Agreement;  (d) it is not
subject to any pending or  threatened  litigation  or  governmental  action that
could interfere with its performance of this Agreement; and (e) such party is in
compliance  with and will comply with all applicable  material  laws,  rules and
regulations,  including  but not  limited to those  promulgated  by the  Federal
Communications Commission, with respect to its rights and obligations under this
Agreement.  Level 3 further  warrants that the services and  equipment  provided
hereunder do not violate or infringe  any common law or statutory  rights of any
party, including without limitation, contractual rights, copyrights, trademarks,
and patents.

17.02  Level 3  warrants  and  represents  to  Teligent  that  its  systems  and
facilities have successfully  accommodated the four-digit date field requirement
for the year 2000 and  beyond  and lose no  functionality  with  respect  to the
introduction of records containing dates falling after January 1, 2000.

17.03    [REDACTED]

17.04 EXCEPT AS SET FORTH IN THIS AGREEMENT,  NEITHER PARTY MAKES AND EACH PARTY
HEREBY  SPECIFICALLY  DISCLAIMS ANY  REPRESENTATIONS  OR WARRANTIES,  EXPRESS OR
IMPLIED,  REGARDING THE PRODUCTS AND SERVICES  CONTEMPLATED  BY THIS  AGREEMENT,
INCLUDING ANY IMPLIED  WARRANTY OF  MERCHANTABILITY  OR FITNESS FOR A PARTICULAR
PURPOSE.
<PAGE>
                                   ARTICLE 18
                                 APPLICABLE LAW

This Agreement is subject to all applicable  federal,  state and local laws, and
regulations,  rulings,  orders,  and  other  actions  of  governmental  agencies
("Rules"),  including, but not limited to: as applicable, the Communications Act
of  1934 as  amended  by the  Telecommunications  Act of  1996,  the  rules  and
regulations of the Federal Communications  Commission ("FCC"), and the obtaining
and continuance of any required approvals, or authorizations from the FCC or any
other governmental agency. Level 3 will use its good faith reasonable efforts to
obtain,  retain, and maintain such approvals and  authorizations.  In performing
their  obligations  under this  Agreement,  the  parties  must  comply  with all
applicable federal, state and local laws, regulations, rules and orders.

                                   ARTICLE 19
                                    INSURANCE

19.01 Each party shall, at its own expense, at all times during the term of this
Agreement,  maintain  in full  force  and  effect a policy  or  policies  of (a)
commercial  general  liability   insurance   (including  coverage  for  premises
operations, independent contractors, products/completed operations, personal and
advertising   injury,   contractual   liability  and  explosion,   collapse  and
underground  hazards) in the amount  (inclusive  of any  amounts  provided by an
umbrella or excess  policy) of at least  [REDACTED];  (b) if eligible,  worker's
compensation  insurance as required by the laws of the applicable  jurisdiction;
and (c) automobile  liability insurance for any vehicles used in the performance
of the services in the amount of at least [REDACTED].

19.02 Each policy of general  liability  insurance  maintained  by a party shall
name the other party hereto as an additional  insured.  All insurance must be on
an occurrence basis, and not on a claims made basis.  Coverage shall be obtained
only from insurers who are rated "A-7" or better in the then most recent edition
of Best's Insurance Reports. Each insurance policy shall provide for a waiver of
the insurer's  subrogation rights against the other party hereto. Each policy on
which  Teligent or Level 3 is an additional  insured  shall  provide  additional
insured  with at least  ten (10) days  prior  written  notice  of  cancellation,
non-renewal,  or  restriction  of coverage.  At least annually and at such other
times as may be requested by Teligent but in any case prior to  commencement  of
performance of the services,  the parties shall cause their respective  insurers
to deliver to the other party certificates of insurance evidencing the existence
of the  coverages  required  under  this  Agreement  or the  relevant  Notice to
Proceed;  provided,  however,  that such certificates  shall be delivered within
thirty (30) days of the execution of this Agreement.
<PAGE>
                                   ARTICLE 20
                                   [REDACTED]

                                   ARTICLE 21
                                  PAYMENT TERMS

21.01  Rates and  charges  will  commence  as set forth in each  Exhibit to this
Agreement.  Unless set forth otherwise in an Exhibit,  (a) any recurring charges
will be billed in advance  each  month or year,  as may be  applicable;  (b) any
nonrecurring  charges  will be billed on the first  invoice  which  includes any
recurring charges; (c) payments are due within thirty (30) days from the date of
the  invoice;  and (d) Level 3 may adjust the rates and  charges for the renewal
terms  (if any).  Invoices  issued  hereunder  which are not paid when due shall
accrue  interest at a rate of [REDACTED] (not to exceed the maximum rate allowed
under state law) until paid in full.

21.02 Teligent is responsible for payment of valid and properly-applied federal,
state and local  taxes,  charges  or  surcharges  imposed  on or based  upon the
provision, sale or use of Level 3's services (excluding charges imposed on Level
3 for the use of public  rights of way and for taxes  based  upon  Level 3's net
income or property).  Unless Teligent is exempt,  Teligent will pay such amounts
upon receipt of an itemized invoice thereof.  Teligent will provide Level 3 with
appropriate documentation of any exemption.

21.03    [REDACTED]

                                   ARTICLE 22
                              TERM AND TERMINATION

22.01 The terms of this Agreement shall be coterminous with the longest term set
forth in any Exhibit hereto.

22.02 In addition to any right of  termination  following a default as set forth
in any  Exhibit,  either  party may  terminate  this  Agreement  or any relevant
Exhibit:  i) upon 30 days  written  Notice  to the  other  party if there is any
judicial, regulatory, or legislative change to, or interpretation of, applicable
laws  and  rules  that  would  render  performance  of  this  Agreement  by  the
terminating party impossible,  illegal or impractical; ii) effective immediately
upon written Notice,  if the other party: (a) becomes  insolvent;  (b) files, or
has  filed  against  it and  not  dismissed  within  60  days,  a  petition  for
bankruptcy; or (c) makes an assignment for the benefit of its creditors; or iii)
if either party fails to make any payment (not  reasonably in dispute)  required
hereunder when due, and such failure  continues for a period of thirty (30) days
after  written  notice  from the other  party;  or iv) if either  party fails to
observe  or perform  the terms and  provisions  of this  Agreement  (other  than
payment terms) and such failure continues for a period of thirty (30) days after
written  notice (or if such  failure is not  susceptible  of a cure  within such
thirty (30) day  period,  cure has not been  commenced  and  diligently  pursued
thereafter to completion).
<PAGE>
22.03 Except as set forth in the  Exhibits,  in the event of  Termination  of a
portion of this  Agreement,  any  services - including  collocation  and related
services  -- not  previously  terminated  will  remain  in  effect  for the term
specified for each non-terminated  service, and the terms and conditions of this
Agreement  will continue to apply to such  services.  Upon  termination  of this
Agreement, all rights of Teligent to order new services cease and Level 3 has no
further  obligations  to  furnish  new  services  to  Teligent.  To  the  extent
applicable,  the  termination  liability set forth in any Exhibit may apply.  In
addition, upon termination of this Agreement, all rights of Level 3 to order new
services  ceases and Teligent has no further  obligation to furnish new services
to Level 3.

23.04 Any  termination  under this section  shall be without any liability to or
obligation  of the  terminating  party other than with  respect to any breach of
obligations under this Agreement prior to termination.
<PAGE>

IN WITNESS WHEREOF,  Level 3 and Teligent have executed this Agreement as of the
date first above written.

                                       LEVEL 3 COMMUNICATIONS, LLC, a

                                       Delaware limited liability company

                                       By___/S/________________________________

                                         Title:





                                       TELIGENT SERVICES, INC.,

                                       a Delaware corporation

                                       By ______/S/____________________________

                                         Title:
<PAGE>
                                    EXHIBIT 1
                    ADDITIONAL TERMS AND CONDITIONS GOVERNING
                                METRO DARK FIBER

As referred to herein, LEVEL 3 COMMUNICATIONS, LLC is the "Grantor" and Teligent
is the "Grantee".

                                    RECITALS

         A. Grantor  intends to construct  and/or is  currently  constructing  a
multiconduit  fiber  optic  communications  system  (the  "Grantor  System")  as
generally described and depicted on Exhibit "A" attached hereto.

         B. Grantor further intends to install within one of the conduits of the
Grantor System a high fiber count fiber optic cable (the "Cable").

         C. Grantee  desires to obtain a license to use the number of fibers and
connecting those points identified in Exhibit "A" attached hereto.

         D. Grantor  desires to grant to Grantee a license to use the fibers and
other  facilities  described  herein,  all upon and  subject  to the  terms  and
conditions set forth below.

                                   ARTICLE 1.

                                   DEFINITIONS

1.01  "Acceptance  Date" shall mean the date when Grantee delivers (or is deemed
to have delivered) notice of acceptance of a Completion Notice with respect to a
Segment in accordance with Article 9.

1.02  "Acceptance Testing" shall have the meaning set forth in Article 9.

1.03  [Intentionally Deleted]

1.04  "Associated  Property"  shall mean the  tangible and  intangible  property
needed for the use of the Grantee Fibers as permitted by this Agreement,  as and
to the extent more  particularly  described in this Agreement,  but excluding in
any and all events any electronic and/or optronic equipment.

1.05  "Cable" shall have the meaning set forth in the Recitals.

1.06  "Completion Notice" shall have the meaning set forth in Section 9.02.

1.07  "Costs" shall mean the actual  direct costs paid or payable in  accordance
with the established  accounting  procedures generally used by Grantor and which
Grantor utilizes in billing third parties for reimbursable  projects [REDACTED].
<PAGE>
1.08  "Dark Fiber" shall have the meaning set forth in Section 15.03.

1.09  "Design, Planning and Engineering Fee" shall be the fee set forth in
Exhibit "B".

1.10  "Dispute Notice" shall have the meaning set forth in Article 24.

1.11  "Effective Date" shall have the meaning set forth in Section 5.01.

1.12  "Fiber Upgrade Notice" shall have the meaning set forth in Section 3.02.

1.13  [Intentionally Deleted]

1.14  "Governmental Authority" shall mean any federal, state, regional,  county,
city, municipal,  local, territorial,  or tribal government,  whether foreign or
domestic,  or  any  department,   agency,  bureau  or  other  administrative  or
regulatory body obtaining authority from any of the foregoing, including without
limitation, courts, public utilities and sewer authorities.

1.15  "Grantee Delay Event" shall mean the failure of Grantee to timely  observe
and perform its obligations and agreements  hereunder,  which failure delays the
construction  and installation of the Grantor System with respect to one or more
Segments.

1.16  "Grantee Fibers" shall have the meaning set forth in Article 3.

1.17  "Grantor Gateway Facilities" shall mean such facilities as may be mutually
agreed upon  between  Grantor and Grantee  which are owned,  leased or otherwise
used  by  Grantor  to  accommodate  or  house  switch  equipment,   fiber  optic
transmission  and/or  associated  ancillary  equipment  to  serve  as  a  switch
terminal, transport concentrator, hub terminal or junction.

1.18  "Grantor System" shall have the meaning set forth in the Recitals.

1.19  "Impositions" shall mean all taxes, fees, levies, imposed duties charges
or withholdings of any nature (including without  limitation  ad  valorem,  real
property,  gross  receipts,  taxes and  franchise,  license  and  permit  fees),
together  with any  penalties,  fines or  interest  thereon  arising  out of the
transactions  contemplated  by this  Agreement  and/or  imposed upon the Grantor
System, or any part thereof, by any Governmental Authority.

1.20 "Interconnection Points" shall have the meaning set forth in Section 10.01.

1.21  "Lateral Segment" shall mean the Segments of the Grantor System identified
as such in Exhibit "A".
<PAGE>
1.22  "Lateral Segment Fee" shall be the fee specified in Exhibit "B".

[REDACTED]

1.24  "Monthly Charge" shall have the meaning set forth in Section 13.02.

1.25  "Minimum Purchase Commitment" shall have the meaning set forth in Section
2.01.

1.26  "Non-Targeted Lateral Segment" shall have the meaning set forth in Section
8.02.

1.27  "Person" shall mean any natural person, corporation,  partnership, limited
liability  company,  business  trust,  joint  venture,  association,  company or
Governmental Authority.

1.28  [Intentionally Deleted]

1.29  "Proprietary Information" shall have the meaning set forth in Article 4 of
the Agreement.

1.30  "Relocating Authority" shall have the meaning set forth in Section 6.03.

1.31  "Required Rights" shall have the meaning set forth in Section 6.01.

1.32  "Route  Miles" shall mean, for each  Segment,  the actual  number of route
miles, or portion thereof, for such Segment as constructed.

1.33  "Scheduled  Completion  Date" shall mean, with respect to each Segment and
subject to Force Majeure Events, the dates set forth on Exhibit "A".

1.34  "Segments" shall have the meaning set forth in Section 2.01.

1.35  "Segment End Points" shall have the meaning set forth in Section 2.01.

1.36  "System Route" shall have the meaning set forth in Section 2.01.

1.37  "Targeted Lateral Segment" shall have the meaning set forth in Section
8.02.

1.38  "Taxes" shall have the meaning set forth in Section 4.05.

1.39  "Term" shall have the meaning set forth in Article 5.

1.39  "Termination Charge" shall have the meaning set forth in Section 20.01.
<PAGE>
                                   ARTICLE 2.
                                  SYSTEM ROUTE

2.01 The  Grantor  System  will  connect  the points  identified  on Exhibit "A"
attached  hereto  (each  point  identified  on  Exhibit  "A" is herein  called a
"Segment  End Point",  the route  between the  applicable  Segment End Points is
herein  called a "Segment",  and all of the Segments  together are herein called
the "System  Route").  The Grantor  System will include the  "Lateral  Segments"
(each of which shall be  considered a "Segment"  for purposes  hereof),  if any,
identified in Exhibit "A". The cumulative  Route Miles for all Segments  ordered
by Grantee pursuant to this Agreement are [REDACTED].  Grantee further agrees to
purchase [REDACTED] additional Grantee Fibers from all of the Segments listed in
Exhibit  "G" when  the same are  available  for  delivery  by Level 3,  bringing
Grantees  total fiber miles to [REDACTED].  Grantee  further agrees to purchase,
within six (6) months of the date of signing the Agreement, additional available
fiber so that the total fiber mileage for Grantee  Fibers  hereunder is at least
[REDACTED]  miles (the  "Minimum  Purchase  Commitment").  Grantee  shall inform
Grantor,  in writing,  of the number of additional Grantee Fibers within six (6)
months from the date of this Agreement. Grantee may satisfy the Minimum Purchase
Commitment only by purchase  [REDACTED] in entire Segments (partial Segments may
not be purchased). In the event Grantee does not inform Grantor of the number of
Grantee  Fibers  desired  necessary to satisfy the Minimum  Purchase  Commitment
within the time  frames set forth  herein,  , then the  [REDACTED]  Fees for the
Minimum  Purchase  Commitment  shall  commence  and be due and  payable  for the
balance of the Term (even though Grantee had not satisfied the Minimum  Purchase
Commitment).

2.02 The  specific  location of the System Route  between  Segment End Points is
subject to change in the sole discretion of Grantor;  however,  the System Route
will connect the Segment End Points for each Segment.

                                   ARTICLE 3.
                                GRANT OF LICENSE

3.01 As of the  Effective  Date for each  particular  Segment of  Grantee  Fiber
delivered by Grantor to Grantee hereunder, Grantor hereby grants to Grantee, and
Grantee  hereby  acquires from Grantor,  [REDACTED]  for the purposes  described
herein,  the  number  of  fibers  set forth in  Exhibit  "A" to be  specifically
identified  in the Cable  between the Segment End Points for such  Segment  (the
"Grantee Fibers"), and an associated and non-exclusive license, for the purposes
described herein, in the Associated Property  respecting such Segment,  all upon
and subject to the terms and conditions set forth herein.

3.02  Grantee may, by written  notice (a "Fiber  Upgrade  Notice")  delivered to
Grantor,  inform  Grantor that  Grantee  desires to purchase  [REDACTED]  to use
additional  fibers (whether of the same type as the Grantee Fibers or otherwise)
either (a) along the same  System  Route as the  Grantee  Fibers,  or (b) within
planned  extensions  to the  then-existing  Grantor  System.  In the event  that
Grantor subsequently  determines to install such additional fibers, then Grantor
shall notify Grantee of such determination.
<PAGE>
3.03 In the event that Grantee has delivered a Fiber Upgrade  Notice and Grantor
has  received  such  notice  prior to its  determination  to install  additional
fibers,  Grantor and Grantee shall negotiate in good faith concerning  Grantee's
acquisition  of  [REDACTED]  a  portion  of such  additional  fibers  (including
negotiation  of the  additional  fees due and  payable by Grantee for the use of
such  additional  fibers).  The Term for use of any additional  fibers shall be,
unless otherwise agreed in writing by the parties,  for a period which commences
upon  delivery  of such  additional  fibers  and which  ends  twenty  (20) years
thereafter;  provided,  however,  that to the extent such extended term requires
Grantor to extend or renew a  Required  Right,  Grantor  shall have the right to
increase  the  Monthly  Charge  in order to  reflect,  in  Grantor's  reasonable
discretion,  the pass  through  (on a pro rata  basis  based  upon the number of
fibers  within  the  Grantor  System) of any  increase  in the  payments,  fees,
charges,  costs or other  expenses  incurred  or to be  incurred  by  Grantor in
connection with the extension or renewal of such Required Right. Notwithstanding
anything  else in this  Agreement  to the  contrary,  the  failure of Grantor to
notify Grantee of its  determination to install  additional fibers under Section
3.02,  or the failure of the parties to  successfully  negotiate  the terms of a
[REDACTED] such additional  fibers,  shall not constitute a default or breach of
this  Agreement  hereunder  and  neither  Grantee  nor  Grantor  shall  have any
liability  to the other for the  performance,  or the  failure to  perform,  any
obligations imposed under Sections 3.02 or 3.03 hereof.

                                   ARTICLE 4.
                                      FEES

4.01  Grantee  agrees to pay,  as  compensation  for  Grantor's  performance  of
incremental design, engineering,  planning and development of the Grantee Fibers
(including but not limited to the Lateral Segments), the [REDACTED] set forth in
Exhibit "B".

4.02 Grantee further agrees to pay, as  compensation  for the use of the Grantee
Fibers, the [REDACTED] Fee as set forth in Exhibit "B". The [REDACTED] Fee shall
be due and  payable  in full,  and  Grantee  shall  have no right of  offset  or
deduction with respect to any installment of the [REDACTED] Fee due hereunder.

4.03 Grantee further agrees to pay, as  compensation  for the  construction  and
installation  of Grantee Fiber within the Lateral  Segments and as  compensation
for the use  thereof,  the  amounts  as set forth on Exhibit  "B" (the  "Lateral
Segment Fee").

4.04 In  addition  to the  foregoing  amounts,  Grantee  shall pay  directly  or
reimburse  Grantor  for all  other  sums,  costs,  fees and  expenses  which are
expressly provided to be paid by Grantee under this Agreement.
<PAGE>
4.05 The  [REDACTED]  Fees shall be as stated in Exhibit "B". The [REDACTED] Fee
shall  commence on the  Acceptance  Date for each Segment,  and will be invoiced
[REDACTED] in accordance with the Agreement.

4.06 All payments made by Grantee  hereunder shall be made without any deduction
or  withholding  for or on account of any tax, duty or other charges of whatever
nature imposed by any taxing or government authority (collectively, "Taxes"). If
either  Grantee or Grantor are or were  required by law to make any deduction or
withholding  from any payment due  hereunder to Grantor,  then,  notwithstanding
anything to the contrary  contained in this Agreement,  the gross amount payable
by Grantee shall be increased so that,  after any such  deduction or withholding
for Taxes,  the net amount  received  by Grantor  will not be less than  Grantor
would have received had no such deduction or withholding  been required.  If any
taxing or government authority asserts that Grantee should have made a deduction
or  withholding  for or on account of any Taxes with respect to all or a portion
of the payments made  hereunder,  or that Grantor should have collected  certain
Taxes from Grantee  which  Grantor did not  collect,  Grantee  hereby  agrees to
indemnify Grantor for such Taxes and hold Grantor harmless on an after-tax basis
from and  against  any  Taxes,  interest  or  penalties  levied or  asserted  in
connection  therewith.  . Taxes will be separately stated in Grantor's invoices.
In the event  Grantee is exempt  from  paying any taxes,  Grantee  will  provide
Grantor with appropriate documentation of such exemption.

                                   ARTICLE 5.
                                      TERM

5.01 The [REDACTED]  with respect to each Segment shall become  effective on the
first day when both (i) the  Acceptance  Date with respect to the Grantee Fibers
within a Segment has occurred and (ii) Grantor has received  payment of all fees
and charged due under this  Exhibit as of the  Acceptance  Date (the  "Effective
Date").  Subject to the provisions of Article 20, the [REDACTED] with respect to
the Grantee Fibers within each Segment shall  terminate on the twentieth  (20th)
anniversary of the Effective Date (the "Term").

5.02 Upon the expiration of the Term respecting a Segment, [REDACTED], Grantee's
rights to use the Grantee Fibers shall revert to Grantor  without  reimbursement
of any of the [REDACTED] Fee or other sums, costs,  fees or expenses  previously
made with respect  thereto,  and from and after such time Grantee  shall have no
further rights or obligations  hereunder with respect thereto unless such rights
or obligations are specifically provided herein to survive the Term.

5.03  Subject to Article 20, this  Exhibit  shall  become  effective on the date
hereof and shall  terminate on the date when all the Terms of the Segments shall
have expired or terminated, except that those provisions of this Agreement which
are expressly  provided herein to survive such termination  shall remain binding
on the parties hereto.
<PAGE>
                                   ARTICLE 6.
                                 REQUIRED RIGHTS

6.01  Grantor  agrees to obtain  and  maintain  in full force and effect for and
during the Term of each Segment all rights, licenses,  permits,  authorizations,
rights-of-way, easements and other agreements which are necessary for Grantor to
obtain in order to permit Grantor to construct,  install and keep installed, and
maintain  the  Grantee  Fibers  within  such  Segment  in  accordance  with this
Agreement  and to convey the  license in the  Grantee  Fibers to Grantee and all
other rights under this Agreement (collectively, the "Required Rights"). Grantee
shall obtain,  prior to the commencement of the Term, and maintain in full force
and  effect  for and  during  the Term of each  Segment  all  rights,  licenses,
permits, authorizations,  franchises and other approvals which are necessary for
Grantee to obtain in order to permit Grantor to grant the license to Grantee and
for Grantee to use the Grantee Fibers.

6.02 In the event Grantor shall receive notice from any grantor or provider of a
Required  Right that  Grantor has failed to observe or perform  its  obligations
under such  Required  Right,  and  Grantor is not  contesting  in good faith the
validity of such claimed or alleged  failure,  Grantor shall give written notice
to Grantee and Grantee may, at its option  (subject to the terms and  provisions
of the  Required  Right and the  ability of third  parties to cure  defaults  of
Grantor  thereunder),  cure or correct such failure and Grantor shall  reimburse
Grantee for the costs and expenses incurred by Grantee in connection therewith.

6.03 If,  after the  Acceptance  Date with  respect  to a  Segment,  Grantor  is
required (i) by any Governmental  Authority under the power of eminent domain or
otherwise,  (ii) by the grantor or provider of any Required Right,  (iii) by any
other Person having the authority to so require (each a "Relocating Authority"),
or (iv) by the  occurrence of any Force Majeure  Event,  to relocate the Grantor
System within such Segment or any portion thereof,  Grantor shall have the right
to either  proceed  with such  relocation,  including,  but not  limited to, the
right,  in good faith,  to  reasonably  determine  the extent and timing of, and
methods  to be  used  for,  such  relocation,  or to  pay  such  amounts  to the
Relocating  Authority as are  necessary  to avoid the need for such  relocation.
Grantee shall be kept fully  informed of all  determinations  made by Grantor in
connection with such  relocation,  and any such relocation  shall be constructed
substantially  in accordance with the construction  specifications  set forth in
Exhibit "C", incorporate fiber meeting or exceeding the specifications set forth
in Exhibit "D" and be subject to Acceptance  Testing Procedures and Standards in
Exhibit "B." Grantee shall reimburse Grantor for its proportionate  share of the
Costs (including  Acceptance  Testing and including amounts paid to a Relocating
Authority to avoid relocation) related to such relocation (to the extent Grantor
has not been  reimbursed by the Relocating  Authority)  allocated to Grantee pro
rata  based on the number of Grantee  Fibers  and the total  fiber  count in the
affected Segments of the Grantor System.
<PAGE>
                                   ARTICLE 7.
                       CONSTRUCTION OF THE GRANTOR SYSTEM

7.01 Grantor will design,  engineer,  install and construct  the Grantor  System
substantially  in accordance with the construction  specifications  set forth in
Exhibit "C", in a workmanlike  manner and in accordance with industry  standards
and  all  applicable  laws.  Such   responsibilities   shall  include,   without
limitation,  preparation of construction drawings,  materials specifications and
materials  requisitions.  The Grantee  Fibers and the conduit  housing the Cable
shall meet or exceed the fiber and conduit  specifications  set forth in Exhibit
"D".   Nothing   contained   herein  shall  prohibit   Grantor  from  commencing
construction  of a portion of a Segment before Grantor has obtained all Required
Rights necessary for all of such Segment.

7.02     Grantor will undertake the Acceptance Testing of each of the Segments.

7.03  Occupancy by Grantee in any Grantor  Gateway  Facility shall be subject to
the execution of a separate colocation  agreement in form mutually acceptable to
both Grantor and Grantee.

7.04  Grantor and Grantee  will  consult  with each other from time to time upon
request to attempt to coordinate  construction  of the Grantor System with other
network construction which may be undertaken by Grantee.

7.05     [REDACTED]

7.06  Notwithstanding  anything to the contrary  contained  herein,  Grantor may
elect,  at its option,  to acquire any portion of the Grantor  System from third
parties  (whether  under a  lease,  sublease,  indefeasible  right  of  use,  or
otherwise  (so long as such rights are  sufficient  to grant Grantee its license
hereunder)) in lieu of constructing and installing the Grantor System respecting
such  portion;  provided,  any  such  acquired  portion  shall  be or have  been
constructed  substantially in accordance with the  specifications and procedures
required  by this  Agreement  except for such  deviations  which do not,  in the
reasonable discretion of Grantor,  materially diminish the utility,  reliability
or expected useful life of the Grantor System. [REDACTED]

                                   ARTICLE 8.
                                LATERAL SEGMENTS

8.01 In the event that  Grantee  desires to have Grantor  construct  and install
additional  Lateral Segments (other than those listed in Exhibit "A") during the
Term,  Grantee may request (in writing)  that Grantor  perform  construction  of
same. Upon receipt of such a request,  Grantor shall  determine  whether it will
construct such additional Lateral Segments; Grantor shall be under no obligation
to construct additional Lateral Segments,  and Grantee shall not be obligated to
contract with Grantor for the construction of any Lateral Segments.
<PAGE>
8.02 A "Targeted  Lateral  Segment"  is a Lateral  Segment to connect a location
where  Grantor  has,  at the time the  written  request  is  submitted,  already
committed  to build and for which  Grantor has  secured or reserved  funding for
construction  (including those Lateral  Segments  identified as Targeted Lateral
Segments on Exhibit "A").  Any Lateral  Segment that is not a "Targeted  Lateral
Segment"  (as of the date of  Grantee's  request for fiber  within such  Lateral
Segment) shall be a "Non-Targeted  Lateral  Segment".  In the event that Grantee
requests  construction of additional  Lateral Segments and Grantor determines to
construct  same,  then  (unless  otherwise  agreed by the  parties)  the Lateral
Segment  Fee  respecting  each  such  Lateral  Segment  shall be  determined  in
accordance with Exhibit "B".

8.03 When physically and  economically  prudent (as determined in Grantor's sole
discretion),  Grantor will construct all Targeted Lateral Segments  diversely to
Grantor's  point of presence only (i.e.,  two distinct  physical  routes will be
used to connect  the  Segment  End Point on the  Grantor's  backbone  network to
Grantor's  point of presence  within or near the  targeted  building).  Building
entrance facilities,  or riser facilities within any building, may or may not be
diverse in Grantor's sole discretion. Grantor shall have discretion to determine
the design and route of all Lateral Segments  (including  decisions  relating to
the location or  locations  of the Segment End  Points).  In the event that (for
Lateral  Segments other than those listed in Exhibit "A") Grantor  determines to
construct a Lateral Segment diversely,  Grantee may (by written notice delivered
no later that ten (10) days after Grantee is informed of Grantor's determination
to construct such Lateral Segment  diversely) elect not to use fibers within the
diverse return route for such Lateral  Segment,  in which event Grantee shall be
entitled to use Grantee  Fibers  within only the  point-to-point  section of the
Lateral  Segment and the Lateral  Segment Fee for such Grantee  Segment shall be
based on the Costs of construction  only for such  point-to-point  section.  The
foregoing  not  withstanding,  Level 3 agrees that with  respect to the Targeted
Lateral  Segments  identified in Exhibit "A" hereto,  that such laterals will be
constructed  diversely.  All other laterals  subsequently  agreed to between the
parties shall be priced and constructed as agreed to between them.

8.04  [REDACTED]  Grantor  shall keep  Grantee  informed of the progress of work
necessary to complete  such  construction,  but Grantee shall not be entitled to
any liquidated damages (as set forth in Section 20.03) related to the failure to
complete construction on or before the date specified in Exhibit "A."

                                   ARTICLE 9.
                        ACCEPTANCE TESTING AND COMPLETION

9.01 Grantor shall test the Grantee Fibers in accordance with the procedures and
standards  specified in Exhibit "E" ("Acceptance  Testing").  Acceptance Testing
shall progress span by span along each Segment as cable splicing progresses,  so
that  test  results  may be  reviewed  in a  timely  manner.  Grantee  shall  be
responsible for the timely  completion of any work or  installation  required in
order for it to place the Grantee Fibers into  operation (and Grantee's  failure
to  complete  such work  shall not be  grounds  for  rejection  of a  Completion
Notice). Grantee shall have the right, but not the obligation, at Grantee's cost
and expense,  to be present to observe the  Acceptance  Testing.  Grantor  shall
provide Grantee with a copy of such test results.
<PAGE>
9.02  Upon the  successful  completion  of  Acceptance  Testing  respecting  any
Segment,  Grantor shall provide written notice of same to Grantee (a "Completion
Notice").  Grantor shall contemporaneously  deliver a copy of the results of the
Acceptance Testing for the entire Segment (if and to the extent that Grantor has
not previously  delivered  same) and Grantee shall,  within  [REDACTED]  days of
receipt of the Completion Notice,  either accept or reject the Completion Notice
(Grantee  shall be  permitted  to reject  only if Grantee  specifies  a material
failure of the Grantee Fibers to satisfy the  requirements of this Agreement) by
delivery  of  written  notice to  Grantor.  In the  event  Grantee  rejects  the
Completion Notice, Grantor shall promptly,  and at no cost to Grantee,  commence
to remedy  the defect or  failure  specified  in  Grantee's  notice.  Thereafter
Grantor shall again conduct Acceptance  Testing and (if successfully  completed)
provide Grantee a Completion Notice with respect to such Segment.  The foregoing
procedure  shall  apply  again and  successively  thereafter  until  Grantor has
remedied all defects or failures specified by Grantee. Any failure by Grantee to
timely reject a Completion  Notice,  or any use of the Grantee Fibers by Grantee
for any purpose other than testing, shall be deemed to constitute acceptance for
purposes  of this  Agreement  and  Grantee  shall be deemed to have  delivered a
notice of acceptance  upon such use or on the  [REDACTED]  after delivery of the
Completion Notice. [REDACTED]

                                   ARTICLE 10.
                             INTERCONNECTION POINTS

10.01  Grantee  shall  have  the  right to  request  that  Grantor  interconnect
Grantee's  communications  system  with the  Grantee  Fibers at the  Segment End
Points and such other points as are  determined and designated by Grantor in its
sole  discretion  during  the  design,  engineering  and  permitting  phases  of
construction  ("Interconnection  Points").  None of the  Interconnection  Points
shall be in any portion of the Grantor System which transits  Canada unless such
interconnection can be accomplished in a fashion which, in Grantor's  judgement,
will not cause either  Grantor or Grantee to be in violation of applicable  laws
or regulations.

10.02  Grantor  may route the  Grantee  Fibers  through  Grantor's  space in any
Grantor Gateway Facilities, in Grantor's sole discretion;  provided such routing
shall not  materially  adversely  affect  Grantee's use of the Grantee Fibers or
Associated Property hereunder and Grantor shall be responsible for all costs and
expenses associated therewith.

10.03 Any work  respecting the Grantor System or the Grantee Fibers  required by
Grantee,  including  (a) splicing of the Grantee  Fibers,  or (b) changes in the
configuration  or other  changes  relating to Grantee's  space or racks shall be
undertaken only by Grantor at Grantee's  request and shall be performed within a
reasonable amount of time consistent with industry accepted  practices;  Grantee
shall (except with respect to splicing and incidental work at Segment End Points
(and such other  points) as previously  identified  between the parties prior to
the execution of this  Agreement,  the costs for which have been included in the
payments due hereunder)  reimburse  Grantor for all Costs incurred in connection
therewith,  plus a management  fee equal to  [REDACTED]  of such Costs.  Grantee
shall  have no right to  perform  work on or  otherwise  physically  access  the
Grantor System, except as expressly provided herein.
<PAGE>
                                   ARTICLE 11.
                                   OPERATIONS

11.01 Subject to the access  restrictions set forth in Article 10, Grantee shall
(at its full cost and expense) have full and complete control and responsibility
for  determining  any  network  and service  configuration  or designs,  routing
configurations,  re-grooming,  rearrangement  or  consolidation  of  channels or
circuits and all related functions with regard to the use of the Grantee Fibers;
provided,  such control and responsibility by Grantee shall not adversely affect
the use by any other  Person of the  Grantor  System  and/or any  electronic  or
optronic equipment used by such Person in connection therewith.

11.02  Grantee  acknowledges  and agrees that  Grantor is not  supplying  nor is
Grantor  obligated to supply to Grantee any optronic or electronic  equipment or
related facilities,  all of which are the sole responsibility of Grantee, nor is
Grantor  responsible  for  performing  any work other than as  specified in this
Agreement.

11.03 Upon not less than one  hundred  twenty  (120) days  written  notice  from
Grantor to Grantee  with  respect to  "Operating  Grantee  Fibers"  (as  defined
below),  Grantor may, at its option substitute for the Grantee Fibers within any
Segment or Segments,  or any portions  thereof,  an equal number of  alternative
fibers within such Segment or portion thereof (which shall thereafter constitute
Grantee Fiber  hereunder),  provided that in such event,  such  substitution (i)
shall be effected at the sole cost of Grantor,  including,  without  limitation,
all disconnect and reconnect costs, fees and expenses; (ii) shall be constructed
substantially in accordance with the  specifications and procedures set forth in
Exhibit  "C",   incorporate   fiber  and  conduit   meeting  or  exceeding   the
specifications  set forth in Exhibit "D", and be tested in  accordance  with the
Acceptance  Testing;  (iii)  shall not  change any  Segment  End Points or other
Interconnection  Points;  and (iv) Grantor shall use all  reasonable  good faith
efforts to minimize any  interruption  in the operation of the Grantee Fibers in
accordance  with Article 20 of the  Agreement.  Substitution  of Grantee  Fibers
shall not affect or extend the Term with  respect to the fibers so  substituted.
For purposes of the  foregoing,  "Operating  Grantee  Fibers" shall mean Grantee
Fibers which have been jumpered to Grantee's space or equipment at a Segment End
Point.  Grantor may substitute  Grantee  Fibers which are not Operating  Grantee
Fibers at any time during the Term without notice to Grantee  (provided that, in
the event  Grantor has  substituted  the Grantee  Fibers,  then at the time such
Grantee  requests  that its fibers be  jumpered to its space or  equipment,  the
substituted  Grantee Fibers will be tested in accordance  with the provisions of
this Agreement).
<PAGE>
                                   ARTICLE 12.
                  MAINTENANCE AND REPAIR OF THE GRANTOR SYSTEM

From and after the Effective Date with respect to each Segment,  the maintenance
of the Grantor  System within such Segment shall be provided in accordance  with
the  maintenance  requirements  and procedures set forth in Exhibit "F" attached
hereto.  The costs of all Scheduled  Maintenance  (as defined in Exhibit "F") of
the Grantee  Fibers  shall be borne by Grantor as a part of the Monthly  Charge;
however,  Grantee shall  reimburse  Grantor for its  proportionate  share of the
Costs of any Unscheduled Maintenance (as defined in Exhibit "F") (if but only if
(i) the  total  Costs of such  Unscheduled  Maintenance  exceeds  five  thousand
dollars ($5,000.00) or (ii) Grantee is the sole user of the Cable),  which Costs
shall be allocated to Grantee pro rata based on the number of Grantee Fibers and
the total fiber count in the affected portion of the Grantor System.

                                   ARTICLE 13.
                                 MONTHLY CHARGE

13.01  Grantor  shall be  responsible  for the payment of the costs of Scheduled
Maintenance of the Grantor System (as defined in Exhibit "F").

13.02 In  consideration  of  Grantor's  responsibilities  under  Section  13.01,
subject to the  adjustments  described in Section  13.03,  Grantee  shall pay to
Grantor each month during each year,  with respect to each  Segment,  commencing
with the Acceptance Date of such Segment and continuing  until the expiration of
the Term with respect to such Segment shall have occurred,  the product obtained
when:  (a)  [REDACTED]  is  multiplied  by (b) the number of Route Miles in such
Segment (the "Monthly Charge").

13.03  The  Monthly  Charge  shall  be  increased  on  each  anniversary  of the
Acceptance Date of the first Segment in which Grantee will receive [REDACTED] by
the increase,  if any, in the Consumer Price Index, All Urban Consumers (CPI-U),
U.S. City Average, published by the United States Department of Labor, Bureau of
Labor Statistics (1982-84 = 100), for the preceding twelve (12) month period. In
the event such index shall cease to be computed or  published,  Grantor  may, in
its reasonable discretion, designate a successor index to be used in determining
any increase to the Monthly Charge.

13.04 The Monthly Charge shall be paid each year by Grantee in twelve (12) equal
installments  due and payable on the first day of each  month.  In the event the
Acceptance Date or termination of the Term of a Segment occurs other than on the
first day of the month, the Monthly Charge shall be prorated.

                                   ARTICLE 14.
                                   IMPOSITIONS

14.01  Grantor  and  Grantee  acknowledge  and  agree  that it is  their  mutual
objective and intent to (i) minimize, to the extent feasible, the administrative
expenses  associated with and the aggregate  Impositions payable with respect to
the  Grantor  System and the  Grantee  Fibers  and (ii)  share such  Impositions
according to their  respective  interests in the Grantor  System and the Grantee
Fibers, and that they will cooperate with each other and coordinate their mutual
efforts to achieve such  objectives  in accordance  with the  provisions of this
Article.
<PAGE>
14.02  Grantor  shall  be  responsible  for  and  shall  timely  pay any and all
Impositions  with respect to the construction or operation of the Grantor System
which  Impositions  are imposed or assessed  prior to the  Acceptance  Date of a
Segment. Notwithstanding the foregoing obligations, Grantor shall have the right
to challenge any such  Impositions so long as the challenge of such  Impositions
does not  materially  adversely  affect  the rights to be  delivered  to Grantee
pursuant hereto.

14.03  Following  the  Acceptance  Date for each Grantor  System and except with
respect to Impositions constituting ad valorem property taxes levied against the
Grantee  Fibers  (which are  addressed in Section  14.04  below),  Grantor shall
timely pay any and all Impositions  imposed upon or with respect to each Grantor
System to the  extent  such  Impositions  have not been or may not  feasibly  be
separately  assessed or imposed  upon or against  the  respective  interests  of
Grantor and Grantee in such Grantor System. Upon receipt of a notice of any such
Imposition, Grantor shall promptly notify Grantee of such Imposition and Grantee
shall pay or reimburse Grantor for its  proportionate  share of such Imposition,
which  share  shall be  determined  (i) to the extent  possible,  based upon the
manner and methodology used by the particular  Governmental  Authority  imposing
such Imposition (e.g., on the cost of the relative property interests,  historic
or projected revenue derived therefrom,  or any combination thereof); or (ii) if
the same cannot be so determined,  then based upon Grantee's proportionate share
of the total fiber count in the affected portion of the Grantor System.

14.04  Following the  Acceptance  Date for each Grantor System and except to the
extent  prohibited by applicable laws or regulations,  Grantee shall  separately
file  returns for and pay any and all ad valorem  property  taxes  imposed on or
assessed  against  the  Grantee  Fibers.  In the event that  applicable  laws or
regulations  require  Grantor to file  returns for and pay any or all ad valorem
property taxes imposed on or assessed against the Grantee Fibers,  Grantor shall
do so and Grantor shall be entitled to reimbursement from Grantee (under Section
14.03) for the ad valorem  property tax  payments  made  respecting  the Grantee
Fibers.

14.05  Notwithstanding any provision herein to the contrary,  Grantor shall have
the right to reasonably  contest any Imposition  assessed against it, (including
by nonpayment of such  Imposition  provided such  nonpayment does not materially
adversely  affect the rights to be delivered to Grantee  pursuant  hereto).  The
out-of-pocket costs and expenses (including reasonable attorneys' fees) incurred
by Grantor in any such  contest  shall be shared by Grantor  and  Grantee in the
same  proportion as to which the parties would have shared in such  Impositions,
as they were  originally  assessed.  Any  refunds  or credits  resulting  from a
contest  brought  pursuant to this Section shall be divided  between Grantor and
Grantee in the same proportion as to which such refunded or credited Impositions
were borne by Grantor and Grantee.  Grantor  acknowledges that Grantee has taken
positions in certain legal proceedings, including Teligent v. Dallas, concerning
the imposition of franchise fees and other  rights-of-way fees on fixed wireless
carriers.  Grantee  reserves the right to take positions that may be contrary to
those of Grantor regarding Impositions. [REDACTED]
<PAGE>
14.06 Grantor and Grantee agree to cooperate in the  preparation  of any returns
or reports relating to the Impositions.  Grantor and Grantee further acknowledge
and agree that the  provisions  of this  Article are  intended  to allocate  the
Impositions  expected to be assessed  against or imposed  upon the parties  with
respect  to the  Grantor  System  based  upon  the  procedures  and  methods  of
computation  by which  Impositions  generally  have been assessed and imposed to
date, and that material  changes in the procedures and methods of computation by
which such  assessments are assessed and imposed could  significantly  alter the
fundamental  economic assumptions  underlying the transactions  hereunder to the
parties.  Accordingly,  Grantor  and Grantee  agree  that,  if in the future the
procedures  or methods of  computation  by which  Impositions  are  assessed  or
imposed against the parties change  materially from the procedures or methods of
computation  by which they are imposed as of the date  hereof,  the parties will
negotiate in good faith an amendment to the  provisions of this Article in order
to preserve,  to the extent reasonably possible,  the economic intent and effect
of this Article as of the date hereof.

                                   ARTICLE 15.
                              USE OF GRANTOR SYSTEM

15.01 Grantee  represents  and warrants that it will use the Grantee  Fibers and
the  license  to  use  granted  hereunder  in  compliance  with  all  applicable
government codes, ordinances, laws, rules and regulations.

15.02 Subject to the provisions of this  Agreement,  Grantee may use the Grantee
Fibers for any lawful purpose.  Grantee  acknowledges  and agrees that it has no
right to use any fibers, other than the Grantee Fibers, included or incorporated
in the Grantor  System,  and that Grantee  shall keep any and all of the Grantor
System free from any liens,  rights or claims of any third party attributable to
Grantee.  Grantee  further  agrees that any  conveyance  of its right to use the
Grantee  Fibers  shall in all  events be  subject to the terms set forth in this
Agreement,  and that Grantee  shall not convey or purport to convey to any third
party  rights that are greater  than the rights  accorded to Grantee  under this
Agreement.

15.03  Notwithstanding  anything to the contrary  contained  in this  Agreement,
Grantee  covenants and agrees that Grantee shall not, that Grantee shall have no
right to, and that  Grantor may enjoin  Grantee  from any  attempt  to,  assign,
sublicense or otherwise  transfer the Grantee Fibers to anyone as Dark Fiber for
a period of four (4) years after the  Acceptance  Date for such Grantee  Fibers.
For purposes hereof,  "Dark Fiber" shall mean fiber provided without  electronic
and/or optronic equipment and which is not "lit" or activated.

15.04  Grantee  shall  not use the  Grantee  Fibers  in a way  which  physically
interferes in any way with or otherwise adversely affects the use of the fibers,
cable or conduit of any other Person using the Grantor System.
<PAGE>
15.05  Grantee  and  Grantor  shall  promptly  notify  each other of any matters
pertaining  to, or the  occurrence  (or impending  occurrence)  of, any event of
which it is aware that could give rise to any damage or  impending  damage to or
loss of the Grantor System.

15.06  Grantee and Grantor  agree to  cooperate  with and support  each other in
complying  with any  requirements  applicable  to their  respective  rights  and
obligations hereunder by any Governmental Authority.

                                   ARTICLE 16.
                              APPROVAL OBLIGATIONS

16.01 Notwithstanding the other indemnification  obligations of the Agreement to
which this  Exhibit is attached as Exhibit 2, to the extent  Grantor is required
under the terms and provisions of any Required Right to indemnify the grantor or
provider  thereof  from  and  against  any and  all  claims,  suits,  judgments,
liabilities, losses and expenses arising out of service interruption, cessation,
unreliability  of or damage to the Grantor  System,  regardless  of whether such
claims, suits, judgments, liabilities, losses or expenses arise from the sole or
partial  negligence,  willful  misconduct  or other  action or  inaction of such
grantor  or  provider  and  its  employees,   servants,   agents,   contractors,
subcontractors  or other  Persons  using the property  covered by such  Required
Right, Grantee hereby releases such grantor or provider from, and hereby waives,
all claims, suits,  judgments,  liabilities,  losses and expenses arising out of
service  interruption,  cessation,  unreliability  of or damage  to the  Grantor
System regardless of whether such claims, suits, judgments,  liabilities, losses
or expenses  arise from the sole or partial  negligence,  willful  misconduct or
other  action  or  inaction,  of such  grantor  or  provider  or its  employees,
servants,  agents,  contractors,  subcontractors  or  other  Persons  using  the
property covered by such Required Right.

                                   ARTICLE 17.
                                   [REDACTED]

                                   ARTICLE 18.
                                    INSURANCE

18.01    [Intentionally Deleted]
18.02    [Intentionally Deleted]
18.03    [Intentionally Deleted]
18.04    [Intentionally Deleted]
18.05    [Intentionally Deleted]
18.06    [Intentionally Deleted]
<PAGE>
18.07 Until the  Effective  Date for a Segment,  Grantor  shall bear all risk of
loss of and damage or  destruction  to the Grantor  System  within such Segment.
Commencing as of the Effective  Date,  any loss,  damage or destruction of or to
the  Grantor  System not  otherwise  required to be insured  hereunder  shall be
treated for all purposes as Unscheduled Maintenance (as defined in Exhibit "F").

                                   ARTICLE 19.
                             [INTENTIONALLY DELETED]

                                   ARTICLE 20.
                                     DEFAULT

20.01    [REDACTED]

         (b) If (i) Grantee  makes a general  assignment  for the benefit of its
creditors,  files a voluntary  petition in  bankruptcy or any petition or answer
seeking,   consenting  to,  or  acquiescing  in   reorganization,   arrangement,
adjustment,  composition,  liquidation,  dissolution or similar relief;  (ii) an
involuntary petition in bankruptcy,  other insolvency protection against Grantee
as filed and not  dismissed  within  120 days;  (iii)  Grantee  fails to pay any
[REDACTED]  or any other sums owed by Grantee  to  Grantor  hereunder,  and such
failure  continues  for a period of thirty (30) days after  written  notice from
Grantor  (which  notice in the case of a  failure  to pay  [REDACTED],  shall be
deemed the same notice, if any, given by Grantor under subsection (a) above); or
(iv) Grantee fails to observe and perform any other terms and provisions of this
Agreement,  and such  failure  continues  for a period of thirty (30) days after
written  notice from  Grantor (or if such failure is not  susceptible  of a cure
within such thirty (30) day period,  cure has not been  commenced and diligently
pursued  thereafter to completion),  then Grantor may (A) terminate this Exhibit
and the Term,  in whole or in part, in which event Grantor shall have no further
duties or obligations  hereunder but Grantee shall remain obligated as specified
below,  and (B)  subject  to the  limitations  imposed  upon  Grantor  under the
[referring to the Article 17 limitations  which have been  deleted],  pursue any
legal remedies it may have under applicable law or principles of equity relating
to such default,  including an action for damages,  specific  performance and/or
injunctive  relief. In the event Grantor shall elect to terminate this Agreement
and the Term, then:

         (i)   [REDACTED]   respecting  all  of  the  Grantee  Fibers  shall  be
immediately  (and without  further  written  notice to Grantee)  terminated  and
revoked, and

         (ii)  Grantee  shall be  liable to pay and  shall  pay to  Grantor  (as
liquidated damages and not as a penalty) the Termination Charge, and

         (iii)  Grantee  shall (at its sole cost and expense and within five (5)
days following such termination) remove from any facilities owned or operated by
Grantor in connection with the Grantor  System,  any and all equipment and other
personal  property  owned by Grantee  and used in  connection  with the  Grantee
Fibers. In the event Grantee shall fail to timely remove its equipment and other
personal  property,  Grantor may, at its option,  either (A) deem such  property
abandoned by Grantee  whereupon title to the same shall pass to Grantor,  or (b)
cause such property to be removed at Grantee's  cost and expense,  which amounts
shall be due and payable by Grantee to Grantor upon demand.

[REDACTED]
<PAGE>
         (c) Any  suspension  of  Grantee's  use of the  Grantee  Fibers  or any
termination of this Agreement or the Term or any removal of Grantee's  equipment
and other  personal  property  pursuant to the foregoing  subsections  shall not
constitute a release or discharge of Grantee from its obligations  hereunder and
Grantor  shall not be liable  to  Grantee  or any  other  person  for  direct or
consequential  damages, or otherwise,  in connection with the proper exercise of
such rights and remedies.  Grantee waives any claim against Grantor, its agents,
employees or contractors for any injury or inconvenience to or interference with
Grantee's  business,  any loss of use or any other loss occasioned by the proper
exercise of Grantor's rights and remedies specified herein.

20.02  If (i)  Grantor  makes  a  general  assignment  for  the  benefit  of its
creditors,  files a voluntary  petition in  bankruptcy or any petition or answer
seeking,   consenting  to,  or  acquiescing  in   reorganization,   arrangement,
adjustment,  composition,  liquidation,  dissolution or similar relief;  (ii) an
involuntary petition in bankruptcy,  other insolvency protection against Grantor
as filed and not dismissed  within 120 days;  (iii) Grantor fails to observe and
perform the terms and  provisions of this  Agreement and such failure  continues
for a period of thirty (30) days after  written  notice from Grantee (or if such
failure is not  susceptible  of a cure within such thirty (30) day period,  cure
has not been commenced and diligently  pursued  thereafter to completion),  then
Grantee may,  subject to Section 20.03 below, (A) terminate this Exhibit and the
Term, in whole or in part,  in which event Grantee shall have no further  duties
or  obligations  hereunder,  and (B)  subject to the  limitations  imposed  upon
Grantee under the Article 14 of the Agreement,  pursue any legal remedies it may
have under  applicable  law or  principles  of equity  relating to such default,
including an action for damages, specific performance and/or injunctive relief.

20.03 If,  other  than as  caused by a Force  Majeure  Event,  Grantor  has not
delivered  a  Completion  Notice (in good  faith)  respecting  a Segment  within
[REDACTED] after the Scheduled Completion Date with respect thereto,  then, from
and after  such date and until the  installation  is  completed,  Grantee  shall
receive a credit  [REDACTED]  off of [REDACTED]  for such Segment (as liquidated
damages and not as a penalty) for each month or partial month (prorated based on
a thirty-day month) of delay  thereafter;  provided,  however,  that in no event
shall the  amount  of the  credit  provided  to  Grantee  hereunder  be  greater
[REDACTED].  In the event  Grantor  fails to  deliver  the  Grantee  Fibers in a
Segment within  [REDACTED] after the Scheduled  Completion Date and otherwise in
accordance  with this  Agreement,  then  either  party  shall  have the right to
terminate this Agreement and Grantor shall, upon such  termination,  [REDACTED],
together with interest thereon  ([REDACTED]) at the Prime Rate [REDACTED].  This
Section  sets forth the sole and  exclusive  remedies  of Grantee  respecting  a
failure of Grantor to complete  installation  of the Grantee  Fibers  within any
Segment on or before the Scheduled Completion Date.

20.04 [REDACTED]

                                   ARTICLE 21
                             [INTENTIONALLY DELETED]
<PAGE>
                                   ARTICLE 22.
                         REPRESENTATIONS AND WARRANTIES

22.01    [Intentionally Deleted]

22.02 Grantor  represents  and warrants that the Segments of the Grantor  System
that it will construct pursuant hereto will be designed, engineered,  installed,
and  constructed  substantially  in accordance  with the terms and provisions of
this Agreement, any and all applicable building,  construction and safety codes,
as well as any and all other applicable  governmental  laws, codes,  ordinances,
statutes and  regulations;  provided  Grantee's  sole rights and  remedies  with
respect  to any  breach  of such  representation  shall  be (i) to  inspect  the
construction,  installation  and splicing of the Grantee Fibers  incorporated in
each Segment and to participate in the Acceptance Testing, during the course and
at the time of the relevant  construction,  installation and testing periods for
each  Segment,   as  provided  herein;  (ii)  if,  during  the  course  of  such
construction, installation and testing any deviation from the specifications set
forth in  Exhibits  "C" or "D" is  discovered  which  is  reasonably  likely  to
materially  adversely affect the operation or performance of the Grantee Fibers,
the construction or installation of the affected portion of the Segment shall be
repaired to such  specification  by Grantor at Grantor's  sole cost and expense;
and (iii) if, at any time prior to the date that is twelve (12) months after the
Acceptance  Date,  Grantee shall notify Grantor in writing of its discovery of a
deviation  from the  specifications  set forth in  Exhibits  "C" or "D" which is
reasonably likely to materially adversely affect the operation or performance of
the Grantee  Fibers,  with respect to any Segment  (which  notice shall be given
within thirty (30) days of such  discovery) the  construction or installation of
the affected portion of such Segment shall be repaired to such  specification by
Grantor at Grantor's sole cost and expense.

22.03 Grantee  acknowledges  and agrees that  Grantee's sole rights and remedies
with  respect to any defect in or  failure of the  Grantee  Fibers to perform in
accordance with the applicable  vendor's or manufacturer's  specifications  with
respect to the Grantee  Fibers  shall be limited to the  particular  vendor's or
manufacturer's  warranty and such  warranties with respect to the Grantee Fibers
shall be assigned to Grantee upon its request.  In the event any  maintenance or
repairs  to the  Grantor  System  are  required  as a result  of a breach of any
warranty made by any manufacturers, contractors or vendors, unless Grantee shall
elect to pursue such remedies itself,  Grantor shall pursue all remedies against
such  manufacturers,  contractors  or vendors on behalf of Grantee,  and Grantor
shall reimburse  Grantee's  costs for any maintenance  Grantee has incurred as a
result of any such breach of warranty to the extent the manufacturer, contractor
or  vendor  pays  such  costs.  Grantor  will  provide  Grantee  with  copies of
applicable vendor warranties within 60 days of execution of this Agreement.

22.04    [REDACTED]

22.05  EXCEPT AS SET FORTH IN THE  FOREGOING  SECTION  22.01 AND 22.02,  GRANTOR
MAKES NO WARRANTY, EXPRESS OR IMPLIED, WITH RESPECT TO THE GRANTEE FIBERS OR THE
GRANTOR  SYSTEM,  INCLUDING  ANY  WARRANTY  OF  MERCHANTABILITY  OR FITNESS  FOR
PARTICULAR PURPOSE, AND ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED.
<PAGE>
                                   Exhibit "A"
               Segment Descriptions and Scheduled Completion Dates

1.       Segment Descriptions

[REDACTED]

2.       Lateral Segment Descriptions

[REDACTED]

3.       Segment End Points for Lateral Segments

         a. For Targeted  Lateral  Segments  which are  connecting  the backbone
network to local exchange carrier central offices ("LEC CO's"),  the Segment End
Point for the Grantee Fiber will be at Grantor's OSX within the LEC CO.  Grantor
shall be responsible  for bringing its fiber to such Segment End Point,  and for
securing any and all agreements,  consents,  permissions or authorizations  from
the LEC.

         b. For Targeted  Lateral  Segments  which are  connecting  the backbone
network to locations  other than LEC CO's, the Segment End Point for the Grantee
Fiber will be at Grantor's  OSX panel in or  contiguous  to  Grantor's  point of
presence  within the  building.  Grantee shall be  responsible  for bringing its
fiber to such  Segment  End  Point,  and for  securing  any and all  agreements,
consents,  permissions  or  authorizations  from the  building  owner or manager
necessary to install such connecting fiber.

         c.  For  Non-Targeted  Lateral  Segments  to which  laterals  are to be
constructed  as agreed to between the parties,  the Segment End Point will be as
negotiated and priced between the parties.

         d.       [Intentionally Deleted]
         e.       [Intentionally deleted]

         f. Any work  required  to connect the  Grantee  Fibers to other  fibers
owned or  procured  by Grantee  (including,  but not  limited  to,  coring  into
Grantor's  manholes,  handholes  or points of  presence)  shall be  performed by
Grantor pursuant to Section 10.03 of the Agreement.
<PAGE>
                                   Exhibit "B"
                                      Fees
A.   License Fee for Segments.

The total  License Fee for the  Grantee  Fibers  meeting  the  Minimum  Purchase
Commitment  (excluding the Lateral  Segments) is  [REDACTED].  Grantee shall pay
Grantor a  [REDACTED].  Grantor  shall  invoice  Grantee  for such  amount by an
invoice submitted prior to[REDACTED].

The balance of the  [REDACTED]  for all of the Segments  (other than the Lateral
Segments)  comprising the Minimum Purchase Commitment  (including those Segments
listed in Exhibit "A" and the balance of the  committed  Segments  necessary  to
satisfy the Minimum Purchase  Commitment)  shall be [REDACTED] on the Acceptance
Date for each Segment. [REDACTED]

B.       Lateral Segment Fees.

The Lateral  Segments  Identified in Exhibit "A" shall be paid for by Grantee as
set forth below:

[REDACTED], shall be paid by Grantee within thirty (30) days of execution of the
Agreement and Grantor will invoice Grantee accordingly.  Within thirty (30) days
of the Acceptance  Date for each Lateral  Segment,  Grantee will pay Grantor for
such Lateral Segments in accordance with the percentages set forth below,  minus
the down payment previously paid by Grantee for the subject Lateral Segment.

         For Targeted Lateral Segments

Payment:  For the Targeted  Lateral Segments listed on Exhibit "A" or classified
as Targeted  Lateral  Segments under Article 8, Grantee will  reimburse  Grantor
[REDACTED]   incurred  by  Grantor  in  connection  with  the  construction  and
installation of such Targeted Lateral Segment [REDACTED]

         For Non-Targeted Lateral Segments

Payment:  For  the  Non-Targeted  Lateral  Segments  listed  on  Exhibit  "A" or
classified  as  Non-Targeted  Lateral  Segments  under  Article 8,  Grantee will
reimburse  Grantor  [REDACTED]  incurred  by  Grantor  in  connection  with  the
construction and installation of such Non-Targeted Lateral Segment, [REDACTED]

Any additional  Lateral Segments  requested by Grantee will be priced by Level 3
as set forth above,  and subject to payment by Grantee in the same manner as set
forth above.

Credit:  If  Grantor  sells  Dark  Fiber to a second  and  third  customer  on a
Non-Targeted Lateral Segment, Grantor shall credit a portion of the fees paid by
each such customer as set forth below:
<PAGE>
2nd Customer - [REDACTED]
3rd Customer - [REDACTED]

Credits  shall be issued  only to the  extent  that the  customer's  payment  to
Grantor is  sufficient  to make such credit to Grantee,  and Grantor shall issue
such credit to Grantee  within thirty (30) days of Grantor's  receipt of payment
from a customer.  Grantee shall have the right to use such credit to off-set the
Cost of  constructing  and  installing any future  Lateral  Segments  ordered by
Grantee and accepted by Grantor.  The total credit shall in no event  [REDACTED]
for such Non-Targeted Lateral Segment, and no credits shall be made with respect
to Targeted Lateral Segments.

2.       General

[REDACTED]

Slack Fiber

         In the event any Lateral  Segment  (other than those  listed in Exhibit
"A") requires the delivery of slack fiber, Grantee shall be responsible for 100%
of the Costs  associated  with  supplying  slack fiber for  Grantee's use in any
manhole.  Grantee shall reimburse Grantor for such Costs within thirty (30) days
after delivery of an invoice for such Costs.
<PAGE>
                                   Exhibit "C"
          Metropolitan (Local Loop) Network Construction Specifications

The intent of this  Exhibit  is to  delineate  the  general  specifications  and
standards for construction of the Grantor System within  metropolitan  networks.
In the event any federal,  state,  local or private  agency having  jurisdiction
shall impose  higher  standards,  Grantor will comply and conform to such higher
standards.  Grantor may deviate from the specifications and standards  described
below in those instances  where either (i) strict  compliance is impractical due
to physical (including  environmental)  conditions,  right-of-way issues or code
restrictions,  or (ii) Grantor has acquired a portion of the Grantor System from
a third party.

                                1. Minimum Depths

o        Minimum cover  required in the placement of conduit shall be 42 inches,
         except in the following instances:

         o        The  minimum  cover  in  borrow  ditches  adjacent  to  roads,
                  highways,  railroads and interstates  shall be 48 inches below
                  the clean-out  line or existing  grade,  whichever is greater.
         o        The  minimum  cover  across  streams,  river  washes and other
                  waterways  shall be 48  inches  below  the  clean-out  line or
                  existing  grade,  whichever is greater
         o        Where conduit crosses  railroads,  the conduit shall be placed
                  at a  minimum  depth of 60  inches  below  the base of rail or
                  below the paralleling drainage ditch, whichever is greater.
         o        At locations where conduit crosses other subsurface  utilities
                  or other structures, the conduit shall be installed to provide
                  a minimum of 12 inches of vertical clearance under the foreign
                  object while maintaining a minimum cover of 42 inches.
         o        In rock, the conduit shall be placed either: (a) 8 inches deep
                  in rock with 36 inches minimum cover;  (b) 8 inch deep in rock
                  with a concrete cap and 30 inches minimum cover;  (c) 8 inches
                  deep in rock with a 1/4 inch steel  plate  cover and 24 inches
                  minimum  cover or (d) in steel pipe  placed on top of the rock
                  with 18 inches  minimum  cover,  whichever  requires the least
                  rock  excavation.  HDPE  conduit  will be  back-filled  with 2
                  inches of select  materials  (bedding)  and 4 inches of select
                  cover in rock areas.
         o        In the case of the use/conversion of conduit systems purchased
                  or leased from third parties or salvaged conduit systems,  the
                  existing depths shall be considered adequate.

                              2. Cable Marking Tape

o        Cable marking tape shall be installed  above all direct buried conduit,
         generally  at a  minimum  of 12 inches  below  the top of rough  grade.
         Conduit installed by means other than direct burial as well as salvaged
         conduit  systems or conduit  systems  purchased from third parties will
         not have cable marking tape installed.

                             3. Conduit Construction

o        Conduits may be placed by means of trenching,  plowing,  jack and bore,
         or directional bore.  Conduit will generally be placed on a level grade
         parallel to the surface, with only gradual changes in grade elevation.
<PAGE>
o        Steel  conduit will be joined with threaded  collars,  welding or other
         industry accepted methods.
o        Railroad  crossings  will be  encased  in HDPE or steel  conduit.
o        All  underground  crossings  of navigable  waterways  will be placed in
         either  HDPE or steel  conduit at a minimum  depth of 20 feet below the
         bottom of the waterway.
o        All conduits  placed on DOT bridges will be  bulletproof  fiberglass or
         galvanized steel.
o        All conduits  placed on bridges  shall have  expansion  joint placed at
         each  structural  (bridge)  expansion joint or at least every 100 feet,
         whichever is the shorter distance.

                              4. Cable Installation

o        The maximum  pulling force to be applied to the fiber optic cable shall
         be 600 pounds.
o        A pulling  swivel  breakaway  rated at 600 pounds  shall be used at all
         times when pulling fiber optic cable.
o        Bends of small radii  (less then 20 times the  outside  diameter of the
         cable) and twists  that may damage  the cable  shall  beavoided  during
         cable placement.
o        The cable shall be lubricated  and placed in accordance  with the cable
         manufacturer  specifications.
o        All splices will be contained in a cable vault or hand hole.
o        A minimum of 60 feet of slack  cable  will be left in all  intermediate
         cable vaults or hand holes.
o        A  minimum  of 50 feet of slack  cable  from  each  cable end (100 feet
         total) will be left in all splice locations.

                         5. Cable Vaults and Hand Holes

o        Cable  vaults  will be placed as required  by local  conditions  and at
         approximately  every  3000  feet in rural  areas  and 500 feet in urban
         areas

o        Cable vaults and hand holes placed in traveled surface streets shall be
         a  minimum  HS-20  loading  rated.

o        Cable vaults and hand holes not installed in traveled  surface  streets
         shall be a minimum HS-10 loading rated.

                             6. Proofing of Conduits

o        Upon  completion  of  conduit  installed,  conduit  shall be proofed to
         verify  continuity and integrity of the conduit system.

o        Proofing  shall be  accomplished  by pulling or blowing a mandrel.  The
         outside diameter of the mandrel or pig shall be a minimum of 80 percent
         of the inside diameter of the conduit.

                                  7. Compliance

o        All work will be done in  accordance  with  federal,  state,  local and
         applicable  private rules and laws regarding  safety and  environmental
         issues, including those set forth by OSHA and the EPA. In addition, all
         work and the  resulting  fiber  system  will  comply  with the  current
         requirements  of all  governing  entities  (FCC,  NEC,  DEC,  and other
         national, state, and local codes).
<PAGE>
                             8. As Built Drawings

o        As-built  drawings for conduit will contain a minimum of the following:

         o        Information  showing the location of running line, relative to
                  permanent  landmarks.
         o        Cable  vault and hand hole  locations.  o Conduit  information
                  (type, length, etc.)
         o        Notation of all deviations from specifications (depth, etc.).
         o        ROW detail (type, centerline distances, boundaries, waterways,
                  road crossings, known utilities and obstacles).
         o        Fiber  optic  cable  data  (type,   manufacturer,   reel  IDs,
                  sequentials, slack coils, splice points, etc.).
         o        Drawings  will be updated  with  actual  field data during and
                  after construction.

         o        Metro area scale shall not exceed 1 inch = 200 feet.
         o        Rural area scale shall not exceed 1 inch = 500 feet.
         o        All deviations from specification (depth, etc.).
         o        As-built  drawings  will be provided  within 90 days after the
                  Acceptance Date in electronic format.

o        As-built  drawings for fiber will  contain a minimum of the  following:

         o        Maps depicting  which streets the Grantee fiber route travels.
         o        Grantee logical loop  configurations and fiber assignments per
                  loop.
         o        Fiber   assignments   to  all   buildings   Grantor   provides
                  connectivity for Grantee.
         o        As-built  drawings  will be provided  within 90 days after the
                  Acceptance Date in electronic format.
<PAGE>
                                   Exhibit "D"
 Metropolitan (Local Loop) Network Fiber, Conduit and Cable Vault Specifications

The intent of this Exhibit is to delineate the manufacturer  specifications  for
the Grantee  Fibers and the conduit  and cable vault  systems  housing the Cable
within  their  metropolitan   networks.   Grantor  may  also  deviate  from  the
specifications and standards described below in those instances where either (i)
strict  compliance  is  impractical  due to physical  (including  environmental)
conditions,  right-of-way  issues  or code  restrictions,  or (ii)  Grantor  has
acquired a portion of the Grantor System from a third party.

                                    1. Fiber

o        In the  metropolitan  segments,  single mode fiber will be used. In any
         case where the routes for Grantor's intercity and metropolitan networks
         converge,  Grantor  shall  have the  right to elect to  install  either
         non-zero dispersion-shifted optical fiber or single mode fiber. Grantor
         may  substitute  alternative  fibers  if and  only if such  alternative
         fibers have performance  specifications which are at least equal to the
         specifications set forth below:

Single Mode Fiber

         [REDACTED]

o        The fiber optic cable shall generally be  single-armored  (except where
         Grantor determines otherwise at their sole discretion)

                                   2. Conduit

         Grantor  uses a  variety  of  conduit  types  within  its  metropolitan
         networks  including the following:

         o        Conduit  supplied  on reels shall be 1-1/4 inch  minimum  High
                  Density Polyethylene  (HDPE), UV stabilized,  SDR 11 or SDR 9.
                  Conduit  shall be  connected  by  coupler.  Conduits  shall be
                  unlubricated with no rope or tape.
         o        Conduit  supplied in sections shall be 1-1/4 inch minimum Poly
                  Vinyl Chloride  (PVC) schedule 40 conduit.  Ends shall be bell
                  and spigot/beveled. PVC shall be connected using a PVC solvent
                  in accordance with PVC conduit manufacturer's recommendations.
                  Conduits shall be unlubricated with no rope or tape.
         o        4 inch  diameter  conduit shall be Poly Vinyl  Chloride  (PVC)
                  schedule 40. Ends shall be bell and spigot/beveled.  PVC shall
                  be  connected  using a PVC  solvent  in  accordance  with  PVC
                  conduit manufacturer's recommendations.
         o        8  inch  and  10  inch  conduit  shall  be  HDPE  smooth  wall
                  polyethylene with a SDR 11 nominal diameter.
         o        Fiberglass  conduit shall be filament  non-metallic,  filament
                  wound epoxy,  suitable for direct burial,  concrete encasement
                  and suspension  from bridge members  without regard to outdoor
                  ambient.  The product  shall  contain  carbon black to provide
                  ultraviolet protection.
         o        Steel conduit shall be galvanized  rigid conduit (GRC).  Steel
                  casings shall be a minimum 35,000 PSI.

                         3. Cable Vaults and Pull Boxes

         o        Cablevaults shall conform to the requirements of ASTM C478 and
                  ASTM C858.  Cable vault and all components  placed in traveled
                  surface  streets  shall be designed to withstand  HS20 loading
                  per AASHTO loading in accordance with ASTM C857.  Cable vaults
                  not placed in traveled  surface  streets  shall be designed to
                  withstand HS10 loading.
         o        Cable vaults of varying sizes will be used.
         o        Each cable  splice  vault  shall be  grounded  using  industry
                  accepted methods.
         o        Cable vaults shall  contain  racking to support  cable runs.
         o        Design of pull boxes  shall  follow  the same  manner as cable
                  vaults.
<PAGE>
                                   Exhibit "E"
Metropolitan (Local Loop) Network Fiber Acceptance Testing Procedures and
  Standards

The  intent  of this  Exhibit  is to  identify  the  fiber  acceptances  testing
procedures  and  standards  used  within the  Grantor's  metropolitan  networks.
Deviations from these  specifications may occur if Grantor acquires a portion of
the Grantor System from a third party pursuant to the Agreement.

1.       All  splices  shall be  fusion  spliced.  Mechanical  splices  are only
         allowed during  temporary  restoration and will be replaced with fusion
         splices.
2.       Fibers shall be terminated with Ultra SC-PC connectors  (typical return
         loss of 0.50 dB).
3.       After  end-to-end  connectivity  on  the  fibers  has  been  completed,
         bi-directional  OTDR span and power meter  testing  will be  completed.
         Grantor  shall perform tests after the fiber cable is installed and the
         splicing  enclosures have been completed and are in their final resting
         configuration  with the cable  vault or hand hole covers  closed.  This
         ensures that no micro or macro bending problems with the cable or fiber
         strands will contribute to the loss/attenuation measurements.
4.       Power  meter  tests  shall be  completed  to verify and insure  that no
         fibers  have  been  crossed  at any of the  splice  points  within  the
         network.  Grantor  shall test and record  power  level  readings on all
         fiber  strands in both  directions of  transmission  (bi-directionally)
         using the 1310 & 1550 nm wavelengths.
5.       All OTDR and power meter tests shall be completed as follows:
         a.       All OTDR  traces  shall be taken  from  both ends of a section
                  (between  adjacent  Locations)  and recorded  using the 1310 &
                  1550 nm  wavelength.  Loss/attenuation  measurements  for each
                  splice point from both directions shall be taken and recorded.
         b.       The    end-to-end    loss   value   as   measured    with   an
                  industry-accepted  laser source and power meter should have an
                  attenuation rating of less than or equal to the following:
                  (1)      At 1310 nm:  (0.40  dB/km x km of cable) + (number of
                           connectors x 0.50) + (0.10 x number of splices).
                  (2)      At 1550 nm:  (0.30  dB/km x km of cable) + (number of
                           connectors x 0.50) + (0.10 x number of splices).
         c.       Grantor's  loss/attenuation  objective  for each  fiber  optic
                  splice is 0.10 dB when measured in one direction  with an OTDR
                  test set (excluding connector loss, which is typically 0.50 dB
                  per  mated  connector  pair).  If after  three  attempts  this
                  parameter is not met, the splice will be marked as Out-Of-Spec
                  (OOS)  and  the  splice  will  remain   provided  the  average
                  loss/attenuation  value of all splices on an individual  fiber
                  basis  shall  not  exceed  0.10  dB for  the  entire  ring  or
                  subsystem.
         d.       For  bi-directional  OTDR testing,  the distance from Location
                  "A" and Location "Z" shall be recorded for each splice  point.
                  The loss/attenuation at each splice point shall be recorded at
                  both  wavelengths  (1310  nm &  1550  nm) in  each  direction.
                  Grantor  shall then  average  the two  readings  to obtain the
                  final average splice loss/attenuation for each splice point of
                  each fiber strand within the fiber optic cable.
<PAGE>
         e.       Each fiber strand color must be recorded along with its buffer
                  tube  color or the ribbon  color.  The laser  source  transmit
                  power level using the 1310 & 1550 nm  wavelengths  will always
                  be recorded  together  with the receive power level reading at
                  the receiving end of the test.

6.    OTDR traces will be taken and splice loss measurements  recorded.  Grantor
      will store OTDR traces on  electronic  media.  Loss  measurements  will be
      recorded using an industry-accepted laser source and a power meter. Copies
      of all data  sheets and tables  and one set of  diskettes  with all traces
      will be provided to Grantee.

7.    Following  emergency  restoral,  Grantor personnel shall perform span test
      documenting end-to-end  attenuation  measurement of each fiber and will be
      completed in both directions at 1310 & 1550 nm wavelengths. Upon permanent
      repair,  new splice loss  readings  should be no greater than the original
      splice loss specifications.
<PAGE>
                                   Exhibit "F"
                     Maintenance Requirements and Procedures
Maintenance

Scheduled  Maintenance.  Routine  maintenance  and repair of the Grantee  Fibers
described in this  section  ("Scheduled  Maintenance")  shall be performed by or
under the direction of Grantor, at Grantor's  reasonable  discretion.  Scheduled
Maintenance shall commence with respect to each Segment upon the Effective Date.
Scheduled Maintenance shall only include the following activities:

o    patrol of Grantor System route on a regularly  scheduled basis,  which will
     not be less than monthly,  unless  hi-rail  access is  necessary,  in which
     case, it will be quarterly;

o    maintenance of a "Call-Before-You-Dig" program and all required and related
     cable locates;

o    maintenance  of sign posts along the Grantor System  right-of-way  with the
     number of the local "Call-Before-You-Dig" organization and the "800" number
     for Grantor's "Call-Before-You-Dig" program; and

o    assignment of fiber  maintenance  technicians to locations  along the route
     of the Grantor System.

Unscheduled  Maintenance.  Non-routine  maintenance  and  repair of the  Grantee
Fibers   which  is  not   included  as   Scheduled   Maintenance   ("Unscheduled
Maintenance")  shall  be  performed  by  or  under  the  direction  of  Grantor.
Unscheduled  Maintenance  shall  commence  with respect to each Segment upon the
Effective Date. Unscheduled Maintenance shall consist of:

o    "Emergency Unscheduled  Maintenance" in response to an alarm identification
     by Grantor's Operations Center,  notification by Grantee or notification by
     any third party of any failure, interruption or impairment in the operation
     of fibers  within the Grantor  System,  or any event  imminently  likely to
     cause the failure,  interruption  or  impairment in the operation of fibers
     within the Grantor System.

o    "Non-Emergency  Unscheduled  Maintenance"  in  response  to  any  potential
     service-affecting  situation  to  prevent  any  failure,   interruption  or
     impairment in the operation of fibers within the Grantor System not covered
     by Scheduled  Maintenance.  Grantee shall  immediately  report the need for
     Unscheduled Maintenance to Grantor in accordance with reasonable procedures
     promulgated  by  Grantor  from time to time.  Grantor  will log the time of
     Grantee's report,  verify the problem and dispatch personnel immediately to
     take corrective action.

Operations Center
<PAGE>
Grantor  shall  operate  and  maintain  an  Operations   Center  ("OC")  staffed
twenty-four  (24) hours a day,  seven (7) days a week by trained  and  qualified
personnel.  Grantor's  maintenance  personnel  shall be  available  for dispatch
twenty-four  (24)  hours a day,  seven (7) days a week.  Grantor  shall have its
first  maintenance   personnel  at  the  site  requiring  Emergency  Unscheduled
Maintenance activity [REDACTED] after the time Grantor becomes aware of an event
requiring  Emergency  Unscheduled  Maintenance,  unless delayed by Force Majeure
Events. Grantor shall maintain a toll-free telephone number to contact personnel
at the  OC.  Grantor's  OC  personnel  shall  dispatch  maintenance  and  repair
personnel along the system to handle and repair problems detected in the Grantor
System:  (i) through the Grantee's  remote  surveillance  equipment  and/or upon
notification by Grantee to Grantor, or (ii) upon notification by a third party.

Grantor will not be responsible  for monitoring the  performance or operation of
the Grantee Fibers; in the event that Grantee detects a failure in the operation
of the Grantee Fibers which may indicate the need for  Unscheduled  Maintenance,
Grantee shall report same to Grantor's OC.

Cooperation and Coordination

o    In performing its services  hereunder,  Grantor shall take workmanlike care
     to prevent  impairment  to the signal  continuity  and  performance  of the
     Grantee  Fibers.  The  precautions  to be taken by  Grantor  shall  include
     notifications to Grantee. In addition,  Grantor shall reasonably  cooperate
     with  Grantee  in  sharing   information  and  analyzing  the  disturbances
     regarding  the cable  and/or  fibers.  In the event that any  Scheduled  or
     Unscheduled    Maintenance   hereunder   requires   a   traffic   roll   or
     reconfiguration   involving  cable,   fiber,   electronic   equipment,   or
     regeneration  or other  facilities of the Grantee,  then Grantee shall,  at
     Grantor's  reasonable request,  make such personnel of Grantee available as
     may be necessary in order to accomplish such  maintenance,  which personnel
     shall  coordinate and cooperate with Grantor in performing such maintenance
     as required of Grantor hereunder.

o    Grantor shall notify Grantee at least  [REDACTED] days prior to the date in
     connection  with any Planned  Service Work Period ("PSWP") of any Scheduled
     Maintenance  and as soon as possible  after  becoming aware of the need for
     Unscheduled Maintenance.  Grantee shall have the right to be present during
     the performance of any Scheduled Maintenance or Unscheduled  Maintenance so
     long as this  requirement  does not  interfere  with  Grantor's  ability to
     perform its  obligations  under the Agreement.  In the event that Scheduled
     Maintenance  is  canceled  or delayed  for  whatever  reason as  previously
     notified,  Grantor shall notify Grantee at Grantor's earliest  opportunity,
     and will comply with the provisions of the previous  sentence to reschedule
     any delayed activity.

Facilities

o    Grantor  shall  maintain  the Grantor  System in a manner which will permit
     Grantee's  use,  in  accordance  with  the  terms  and  conditions  of  the
     Agreement.

o    Grantee will be solely responsible for providing and paying for any and all
     maintenance of all electronic,  optronic and other equipment, materials and
     facilities  used by Grantee in connection with the operation of the Grantee
     Fibers,  none of  which  is  included  in the  maintenance  services  to be
     provided hereunder.

Cable/Fibers

o    Grantor  shall  perform  appropriate  Scheduled  Maintenance  on the cables
     contained in the Grantor  System in accordance  with Grantor's then current
     preventive  maintenance  procedures which shall not  substantially  deviate
     from standard industry practice.

o    Grantor shall have qualified  representatives  on site any time Grantor has
     reasonable  advance  knowledge that another person or entity is engaging in
     construction  activities or otherwise  digging  within five (5) feet of any
     cable.
<PAGE>
o    Grantor shall maintain sufficient capability to teleconference with Grantee
     during an Emergency  Unscheduled  Maintenance  in order to provide  regular
     communications  during the repair  process.  When  correcting  or repairing
     cable discontinuity or damage, including but not limited to in the event of
     Emergency Unscheduled Maintenance,  Grantor shall use reasonable efforts to
     repair   traffic-affecting   discontinuity   [REDACTED]   after   Grantor's
     representatives  arrival at the problem site.  In order to accomplish  such
     objective, it is acknowledged that the repairs so effected may be temporary
     in nature. In such event, within twenty-four (24) hours after completion of
     any such  Emergency  Unscheduled  Maintenance,  Grantor shall  commence its
     planning for permanent repair, and thereafter promptly shall notify Grantee
     of such  plans,  and  shall  implement  such  permanent  repair  within  an
     appropriate  time  thereafter.  Restoration of open fibers on fiber strands
     not  immediately  required  for service  shall be  completed  on a mutually
     agreed-upon  schedule.  If the fiber is required for immediate service, the
     repair shall be scheduled for the next available PSWP.

o    In   performing   repairs,   Grantor   shall   comply  with  the   splicing
     specifications  as set forth in  Exhibit  "E".  Grantor  shall  provide  to
     Grantee any  modifications to these  specifications  as may be necessary or
     appropriate in any particular instance.

o    Grantor's representatives that are responsible for initial restoration of a
     cut cable shall carry on their vehicles the typically appropriate equipment
     that would  enable a temporary  splice,  with the  objective  of  restoring
     operating capability in as little time as possible.  Grantor shall maintain
     and supply an inventory of spare cable in storage  facilities  supplied and
     maintained  by  Grantor  at  strategic   locations  to  facilitate   timely
     restoration.

Planned Service Work Period

Scheduled  Maintenance  which is  reasonably  expected  to  produce  any  signal
discontinuity  must be  coordinated  between the parties.  Generally,  this work
should be scheduled after midnight and before 6:00 a.m. local time. Major system
work, such as fiber rolls and hot cuts,  will be scheduled for PSWP weekends.  A
calendar  showing approved PSWP will be agreed upon in the last quarter of every
year for the year to come. The intent is to avoid jeopardy work on the first and
last weekends of the month and high-traffic holidays.

Restoration

o    Grantor shall respond to any event giving rise to the need for  Unscheduled
     Maintenance  (in any event,  an "Outage") as quickly as possible  (allowing
     for  delays  caused  by  Force  Majeure  Events)  in  accordance  with  the
     procedures set forth herein.
<PAGE>
o    When restoring a cut cable in the Grantor System, the parties agree to work
     together to restore all traffic as quickly as possible.  Grantor,  promptly
     upon arriving on the site of the cut, shall  determine the course of action
     to be taken to  restore  the  cable and shall  begin  restoration  efforts.
     Grantor  shall  splice  fibers  tube by tube or  ribbon  by ribbon or fiber
     bundle by fiber bundle,  rotating  between tubes or ribbons operated by the
     parties having an interest in the cable, including Grantee, Grantor and all
     future fiber users of the system (collectively, the "Interest Holders"), in
     accordance with the following  described  priority and rotation  mechanics;
     provided that,  operating fibers (i.e.,  fibers which have been jumpered to
     Grantee's,  Grantor's or another  party's space or equipment) in all buffer
     tubes  or  ribbons  or  fiber   bundles   shall  have   priority  over  any
     non-operating fibers in order to allow transmission systems to come back on
     line;  and provided  further that,  Grantor will continue such  restoration
     efforts until all lit fibers in all buffer tubes or ribbons are spliced and
     all traffic  restored.  In general,  and except to the extent prohibited by
     applicable laws, priority among Interest Holders affected by a cut shall be
     determined on a rotating  restoration-by-restoration and Segment-by-Segment
     basis, to provide fair and equitable  restoration  priority to all Interest
     Holders.  Grantor  will  provide  upon  Segment  completion  a  System-wide
     rotation  mechanism  on a  Segment-by-Segment  basis  so that  the  initial
     rotation  order of the  Interest  Holders in each  Segment is varied  (from
     earlier  to later in the  order),  such that as  restorations  occur,  each
     Interest  Holder has  approximately  equivalent  rotation  order  positions
     across the Grantor  System.  Additional  participants in the Grantor System
     that become  Interest  Holders  after the date hereof shall be added to the
     restoration rotation mechanism.

o    The goal of emergency  restoration  splicing shall be to restore service as
     quickly as  possible.  This may require the use of some type of  mechanical
     splice, such as the "3M FiberLock",  to complete the temporary restoration.
     Permanent  restorations  will  take  place as soon as  possible  after  the
     temporary splice is complete.

Subcontracting

Grantor may subcontract any of the maintenance services hereunder; provided that
Grantor shall  require the  subcontractor(s)  to perform in accordance  with the
requirements and procedures set forth herein.  The use of any such subcontractor
shall not relieve Grantor of any of its obligations hereunder.
<PAGE>
                                    EXHIBIT G
                      PLANNED ADDITIONAL METRO FIBER BUILDS
                                   [REDACTED]



                                    EXHIBIT H
                                   [REDACTED]
<PAGE>
                                    EXHIBIT 2
                    ADDITIONAL TERMS AND CONDITIONS GOVERING
                                    NATIONAL
                               WAVELENGTHS SERVICE

                                    ARTICLE 1
                                   DEFINITIONS

1.1  "Acceptance  Date" shall mean the date when Teligent delivers (or is deemed
     to have delivered) notice of acceptance of a Completion Notice with respect
     to a Route of Capacity in accordance with Article 5.

1.2  "Acceptance Testing" shall have the meaning set forth in Article 5.

1.3  [Intentionally Deleted]

1.4  "Capacity" shall mean a specific or a combination of more than one specific
     10GB unprotected  virtual  channel(s) (or wavelength(s)) on Level 3's dense
     wave division multiplexing network ("Level 3 Network") between the "A end "
     and the  corresponding "Z end" locations  identified listed in Appendix "A"
     attached hereto,  along with the ports  associated with those  wavelengths.
     The Capacity shall be limited, both as a minimum and as a maximum, to 10GB.
     Future orders for Capacity shall be provided  hereunder and governed by the
     terms hereof if, and only if: i) such capacity meets the specifications set
     forth above;  and ii) a written order covering such future  capacity orders
     is executed by the  parties;  such  capacity,  when  ordered in writing and
     accepted  reasonably  by Level 3, shall be  included in the  definition  of
     "Capacity"  hereunder and shall be delivered in  accordance  with the terms
     hereof.

1.5  "Completion Notice" shall have the meaning set forth in Section 5.2.

1.6  "Distribution  Node" shall  mean,  for each  Segment of Capacity  along the
     Route  listed in Appendix A, each Level 3 gateway or synergy site along the
     Route on the Level 3 Network  where  Capacity  could,  but not  necessarily
     will, be delivered to Teligent for distribution by Teligent.

1.7  "Effective Date" shall have the meaning set forth in Section 3.1.

1.8  "End Point" shall mean the Level 3 Distribution  Node identified  either as
     the "A end  Distribution  Node" or the  corresponding  "Z end  Distribution
     Node" on  Appendix  "A" (at  each  End  Point,  the  Capacity  will be made
     available  to Teligent by Level 3 and Traffic will be delivered by Teligent
     to Level 3).

1.9  "Fee"  and  "Fees"  shall  refer to any and all of the fees set  forth  and
     described in Appendix A hereto.

1.10 "Level 3 Network" is defined in Section 1.4.

1.11 "PO&M Charge" shall mean the charge specified in Section 7.3.
<PAGE>
1.12 [Intentionally Deleted]
1.13 - 1.15 [Intentionally Deleted]
1.16 [Intentionally Deleted].

1.17 "Route"  shall mean the  physical  path  along the Level 3 Network  used to
     deliver the Capacity between the End Points, and is defined in section 2.2.

1.18 "Segment" shall mean a segment of Capacity with the combination of Segments
     comprising the Route.

1.19 "Wavelengths Term" shall have the meaning set forth in Article 3.
1.20 "Traffic" shall have the meaning set forth in Section 2.1.
     [REDACTED]

                                    ARTICLE 2
                             LICENSE TO USE CAPACITY

2.1 Commencing with the Effective Date [REDACTED],  Level 3 grants to Teligent a
    license to use the Capacity along each Route  [REDACTED]  under and pursuant
    to the terms of this  Agreement.  The Route  between the End Points shall be
    the  shortest  Level 3 Route  between such End Points.  Teligent  shall have
    exclusive  rights  in  and to  the  Capacity  delivered  hereunder  for  the
    Wavelengths  Term (as such  Wavelengths  Term is extended in accordance with
    Section  3.2),  and Level 3 shall not be permitted to sell or otherwise  use
    any portion of the Capacity either itself or for delivery to others.  To use
    the  Capacity,  Teligent must provide to Level 3, at both End Points on each
    Route, [REDACTED] ("Traffic"), which Traffic will thereafter be delivered by
    Level 3, in like format, to the opposite and corresponding End Point of that
    Route identified in Appendix "A".  Capacity may be terminated only at an End
    Point and not at any  Distribution  Node along the Route.  Teligent shall be
    solely responsible for providing all interconnection  equipment used both to
    deliver to or to accept the  Capacity  from Level 3 in the formats set forth
    in this Agreement and for any and all protection schemes Teligent chooses to
    implement respecting the Traffic.

2.2 The  Traffic  will  travel an  established  Route  between the End Points as
    designated in Appendix "A." Upon the mutual agreement of the parties,  Level
    3 and  Teligent  may agree to modify the Route or any  Segment  of  Capacity
    during the Wavelengths Term; provided,  however, that Level 3 shall not have
    the unilateral right to alter the Route without Teligent's permission.

                                    ARTICLE 3
                                      TERM

3.1 The  license  with  respect  to each Route of  Capacity  within a Ring shall
become  effective  [REDACTED].  Subject to the  provisions  of  Article  12, the
license with respect to the Capacity within each Route of Capacity [REDACTED].
<PAGE>
3.2 Upon the scheduled expiration of the Wavelengths Term respecting a Ring, the
Wavelengths  Term  shall  continue  on a  month-to-month  basis  until or unless
previously  terminated  by either  party on one hundred  eighty (180) days prior
notice  by  the  other.   A  monthly   recurring   charge  of   [REDACTED]   per
[REDACTED]shall  apply  during any such  month-to-month  extension  of the term.
After expiration or termination of the Wavelength Term, all rights to the use of
the Capacity therein shall revert to Level 3 without reimbursement of any of the
Fees or other  sums,  costs,  fees or  expenses  previously  made  with  respect
thereto,  and from and after such time Teligent  shall have no further rights or
obligations hereunder with respect thereto unless such rights or obligations are
specifically provided herein to survive the Term.

3.3 This Exhibit shall become  effective on the date hereof and shall  terminate
at  the  conclusion  of the  Wavelengths  Term  [REDACTED],  except  that  those
provisions of this Exhibit which are expressly  provided  herein to survive such
termination shall remain binding on the parties hereto.

                                    ARTICLE 4
                                 BILLS AND FEES

4.1 Teligent  agrees to pay, as  compensation  for the use of the Capacity,  the
Fees for each Route of  Capacity  set forth in Appendix  "A".  For each Route of
Capacity,  the  recurring  charges set forth in Appendix "A" shall be based upon
[REDACTED].

[REDACTED]

4.2 In  addition  to the  foregoing  amounts,  Teligent  shall pay  directly  or
reimburse Level 3 for all other reasonable sums,  costs, fees and expenses which
are expressly provided to be paid by Teligent under this Exhibit.

4.3 Level 3 will send Teligent invoices for all Fees due hereunder in accordance
with the invoices provision of the Agreement (Article 21).

4.4 All payments made by Teligent  hereunder shall be made without any deduction
or  withholding  for or on account of any tax, duty or other charges of whatever
nature imposed by any taxing or government authority (collectively, "Taxes"). If
either  Teligent or Level 3 are or were required by law to make any deduction or
withholding  from any payment due  hereunder  to Level 3, then,  notwithstanding
anything to the contrary  contained in this Agreement,  the gross amount payable
by Teligent shall be increased so that,  after any such deduction or withholding
for  Taxes,  the net  amount  received  by Level 3 will not be less than Level 3
would have received had no such deduction or withholding  been required.  If any
taxing  or  government  authority  asserts  that  Teligent  should  have  made a
deduction or withholding for or on account of any Taxes with respect to all or a
portion of the payments made  hereunder,  or that Level 3 should have  collected
certain  Taxes from  Teligent  which Level 3 did not  collect,  Teligent  hereby
agrees to  indemnify  Level 3 for such  Taxes and hold  Level 3  harmless  on an
after-tax  basis from and against any Taxes,  interest  or  penalties  levied or
asserted in connection  therewith.  Taxes will be separately stated in Level 3's
invoices.  In the event Teligent is exempt from paying any taxes,  Teligent will
provide Level 3 with appropriate documentation of such execution.
<PAGE>
                                    ARTICLE 5
                        ACCEPTANCE TESTING AND COMPLETION

5.1  [REDACTED]  Level 3 shall test the  Capacity (on a Route by Route basis) in
accordance with Level 3's standard  procedures and generally  accepted  industry
practices  ("Acceptance  Testing").  Level 3 shall  provide  Teligent with prior
notice of the date and time of  Acceptance  Testing and Teligent  shall have the
right, but not the obligation,  at Teligent's cost and expense, to be present to
observe the Acceptance Testing.  Level 3 and Teligent agree that they shall each
use best efforts to,  within  thirty (30) days of  execution  of the  Agreement,
negotiate the standards applicable to the "Acceptance Testing." Each party shall
be reasonable in negotiating  such standards,  but in the event that the parties
are unable to agree on  applicable  standards,  this  Exhibit may be  terminated
without  either party  incurring  any liability to the other and any monies paid
hereunder shall be returned to the paying party.  The parties may mutually agree
to extend the time  periods  set forth in this  Section.  Upon  completion,  the
Acceptance  Testing  Standards  may  be  modified  upon  a  signature  of a Vice
President or above of each company.

5.2      When the results of the  Acceptance  Testing  show that the Capacity so
         tested is operating  substantially  in conformity  with the  applicable
         specifications  therefor,  Level 3 shall provide written notice of same
         to Teligent (a  "Completion  Notice"),  which  Completion  Notice shall
         state the results of the Acceptance  Testing.  Teligent  shall,  within
         twenty (20) days of receipt of the Completion Notice,  either accept or
         reject the  Completion  Notice  (Teligent  shall be permitted to reject
         only if  Teligent  specifies  a  material  failure of the  Capacity  to
         operate in accordance with the applicable  specifications  therefor) by
         delivery of written  notice to Level 3. In the event  Teligent  rejects
         the  Completion  Notice,  Level  3  shall  promptly,  and at no cost to
         Teligent,  commence  to remedy  the  defect  or  failure  specified  in
         Teligent's notice.  Thereafter,  Level 3 shall again conduct Acceptance
         Testing and (if successfully  completed)  provide Teligent a Completion
         Notice with respect to such Route of  Capacity.  This  procedure  shall
         apply again and  successively  thereafter by Level 3 until the Capacity
         meets the  specifications.  Any failure by Teligent to timely  reject a
         Completion Notice, or any use of the Capacity by Teligent  ([REDACTED])
         for any  purpose  other  than  testing,  shall be deemed to  constitute
         acceptance  [REDACTED]  for purposes of this Exhibit and Teligent shall
         be deemed to have delivered a Notice of Acceptance  upon such use or on
         the  twenty-first  (21st) day after delivery of the Completion  Notice.
         However, implied acceptance shall not relieve Level 3 of its obligation
         to  insure   that  the   Capacity,   as  an   initial   matter,   meets
         specifications.

                                    ARTICLE 6
                                 INTERCONNECTION

Teligent  shall be solely  responsible  for all Traffic until it is delivered to
Level 3 (in the format set forth in Section 2.1 of this Agreement) and after the
Traffic is redelivered to Teligent at the terminating End Point. The demarcation
point for the Capacity will be [REDACTED].  The Teligent will have the following
access options for the Capacity:

1.   Where  Teligent  has secured  colocation  space  within the End Point,  the
     Capacity  can  be  delivered  via a  cross-connect  and  terminated  at the
     colocation cabinet or a fiber patch panel within the space. [REDACTED]
2.   Where Teligent is located within the same building as the End Point,  Level
     3 will  provide  fiber  extension or riser  facilities  and  terminate  the
     Capacity  at an OSX  panel  within  the  Teligent  POP.  Teligent  will  be
     responsible  for all  Costs (as  defined  in  Exhibit  1 of the  Agreement)
     incurred to provide the extension plus [REDACTED]%
3.   Teligent may choose to have the Capacity  delivered to its POP in a Level 3
     On-Net,  fiber-connected  building.  Level 3 will deliver the Capacity over
     its metro fiber to an OSX panel in the Teligent POP. Any  incremental  Cost
     (as defined in Exhibit 1 of the Agreement) incurred to deliver the Capacity
     will be reimbursed by Teligent at actual cost plus [REDACTED]%An additional
     non recurring  charge will be assessed for the metro fiber pair.  This will
     be calculated at $[REDACTED] per DS 0 route mile for the logical loop.
<PAGE>
Teligent  shall be permitted to cross  connect the Traffic once  redelivered  to
Teligent  with  and into any  local  carrier  (including  Level 3)  selected  by
Teligent.   Level  3  makes  no  representation   or  warranty   respecting  the
availability  or performance  of services or networks  supplied by third parties
beyond the End Points.

                                    ARTICLE 7
                            SERVICE LEVEL AGREEMENTS,
                        POWER, OPERATIONS AND MAINTENANCE

7.1 The ongoing "Service Level Agreement" applicable to the Capacity is attached
hereto as Appendix "B".  Credits  shall be given off of the  recurring  Fees set
forth in Appendix "A".

7.2 Should any condition  exist in any Capacity that may impair the integrity of
such Capacity,  Level 3 shall  initiate or cause to be initiated  maintenance on
such Capacity which may include the  deactivation of such Capacity in accordance
with  Article  20 of the  Agreement.  Level 3 shall,  to the  extent  reasonably
practicable,  advise  Teligent  in  writing  at least ten (10) days prior to the
initiation  of a  planned  maintenance  operation  which  will or is  likely  to
interfere  with the  operation of the  Capacity,  and of the timing and scope of
such planned maintenance operation. If any maintenance shall require redesign of
Teligent's  network  or  transfer  of  Teligent's  customers,  Level 3 will  use
reasonable efforts to minimize disruptions in the Capacity.

7.3 Teligent shall pay to Level 3 [REDACTED] an annual recurring charge (the "PO
& M Charge") equal to  [REDACTED] of the Total  Wavelength Fee (as set forth in
Appendix  "A") per year  [REDACTED].  The PO & M Charge is intended to cover the
expenses of supplying power,  operations and maintenance  services  necessary to
continue effective availability of the Capacity for the Wavelength Term.

7.4      [Intentionally Deleted]

7.5 The PO & M Charge (subject to Article 4) shall be paid each year by Teligent
in twelve (12) equal  installments  due and payable on the first business day of
each month.  In the event the  Acceptance  Date or  expiration  of the Term of a
Route occurs  other than on the first day of the month,  the PO & M Charge shall
be prorated.

                                    ARTICLE 8
                                 USE OF CAPACITY

8.1 Teligent represents and warrants that it will use the Capacity in compliance
with all applicable government codes, ordinances, laws, rules and regulations.

8.2 Subject to the provisions of this  Agreement,  Teligent may use the Capacity
for any lawful  purpose.  Teligent  acknowledges  and agrees that its rights are
limited to the use of the Capacity  only, and that Teligent shall keep Level 3's
Network free from any liens, rights or claims of any third party attributable to
Teligent.
<PAGE>
Teligent  shall not knowingly use the Capacity in a way which  interferes in any
way with or  otherwise  adversely  affects the use of the Level 3 Network by any
other entity using Level 3's Network or capacity  therein.  Teligent will remedy
any such  interference  (or commence  such remedy and prosecute it diligently to
completion) within thirty (30) days written notice of the same provided by Level
3.

8.4 Level 3 will make available Colocation space to Teligent pursuant to Exhibit
    "3" to the Agreement.

8.5 Teligent  agrees that it shall "beta test" the capacity in Ring 4 identified
in  Appendix  "C" hereto (the "Beta  Capacity")  under the  following  terms and
conditions.  For a period of time that commences with the initiation of delivery
of the Beta Capacity to Teligent and which ends upon the delivery of notice from
Level 3 notifying Teligent of the end of the BETA Period  (hereinafter the "BETA
Period"),  such  Capacity  will be provided  to  Teligent  and tested by Level 3
pursuant to the terms and conditions of this Section 8.5.

[REDACTED]

Once  the  Beta  Capacity  is  performing  materially  in  accordance  with  the
Acceptance  Testing  criteria and the Service Level  Agreements  applicable  for
Capacity  hereunder,  Level 3 may transition  Teligent to general  availability,
provide  Teligent with a Completion  Notice in accordance with Article 5 and the
Acceptance Date mechanism of Article 1.1 shall apply. After the Acceptance Date,
the provisions of this Exhibit  (except for those set forth in this Section 8.5)
shall control the provisioning of the Beta Capacity.

8.6  [REDACTED]

                                    ARTICLE 9
                             [INTENTIONALLY DELETED]

                                   ARTICLE 10
                             [INTENTIONALLY DELETED]

                                   ARTICLE 11
                             [INTENTIONALLY DELETED]

                                   ARTICLE 12
                    DELAY IN COMPLETION/TERMINATION LIABILITY

12.1     [Intentionally Deleted]
12.2     [Intentionally Deleted]
<PAGE>
12.3     Notwithstanding  anything  contained in this Agreement to the contrary,
         Teligent's sole and exclusive  remedy with respect to poor  performance
         of the  Capacity  or any  failure of the  Capacity  to meet the service
         levels  set forth in  Appendix  "B" shall be the right to  receive  the
         credits due under  Appendix "B" or to  terminate  this  Agreement.  If,
         other  than  as  caused  by a  Force  Majeure  Event,  Level  3 has not
         delivered a Completion  Notice (in good faith)  respecting  any Ring of
         Capacity  within  ninety  (90)  days  after  the  applicable  "Earliest
         Available  Date" set forth on Appendix "A",  then,  from and after such
         date and until the  installation  is completed,  Teligent shall receive
         (as its sole and exclusive remedy for a failure to deliver a Completion
         Notice  on or  before  the  "Earliest  Availability  Date") a credit of
         [REDACTED]  percent off of the monthly  recurring Fees for such Ring of
         Capacity (as liquidated damages and not as a penalty) for each month or
         partial  month  (prorated  based  on  a  thirty-day   month)  of  delay
         thereafter; provided, however, that in no event shall the amount of the
         credit provided to Teligent  hereunder be greater than  [REDACTED].  In
         the event Level 3 continues to fail to deliver the Ring of Capacity for
         [REDACTED] months after the scheduled  completion date and otherwise in
         accordance with this Agreement,  then either party shall have the right
         to terminate the affected Ring.

         Teligent  shall have the right to terminate  and  discontinue  affected
         Capacity  prior to the end of the agreed  Term  without  payment of any
         applicable  termination charge if: (i) such Capacity is Unavailable (as
         defined in Appendix B) on two or more separate occasions of [REDACTED],
         and (ii)  following  written  notice  thereof from Teligent to Level 3,
         Level 3 has an Unavailability event of [REDACTED] immediately following
         said notice;  and iii) Level 3 is thereafter  given the opportunity to,
         within  thirty  (30)  days,  replace  the  transmission  system for the
         affected  Segment of Capacity and Level 3 thereafter  has an [REDACTED]
         immediately  following  the  replacement.  Teligent may only  terminate
         Service which is affected by Unavailability events as set forth herein,
         and must  exercise its right to terminate  any affected  Service  under
         this  Section,  in  writing,  no later than  thirty (30) days after the
         Unavailability event giving rise to a right of termination hereunder.

12.4     In the event Teligent  terminates  this Exhibit (other than as a result
         of a default by Level 3) or in the event that Level 3  terminates  this
         Exhibit as a result of a default by Teligent,  then Teligent  shall pay
         to Level 3 a  termination  charge (as  liquidated  damages and not as a
         penalty):

         [REDACTED]

                                   ARTICLE 13
                             [INTENTIONALLY DELETED]

                                   ARTICLE 14
                         REPRESENTATIONS AND WARRANTIES

14.1  EXCEPT AS SET FORTH IN ARTICLE 7,  LEVEL 3 MAKES NO  WARRANTY,  EXPRESS OR
IMPLIED, WITH RESPECT TO THE CAPACITY, INCLUDING ANY WARRANTY OF MERCHANTABILITY
OR FITNESS FOR PARTICULAR PURPOSE,  AND ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY
DISCLAIMED.

                                   ARTICLE 15

15.1 Upon request of either party,  the parties shall discuss in good faith (but
shall not have an obligation to agree) upon a migration  plan in which  Teligent
would move from capacity to Level 3 dark fiber and receive credits for sums paid
under this Exhibit.

                                   ARTICLE 16

16.1 Teligent may terminate  without  liability any Wavelength  Service Route of
Capacity  used  directly  in  connection  with  any  Collocation  Space  if such
Collocation  Space is no longer  provided by Level 3 either as  permitted  under
this Agreement or as a result of a default by Level 3.
<PAGE>
                                  Appendix "A"

Teligent purchases the following Capacity at the rates set forth below:

[REDACTED]

For use of the Capacity:

Teligent shall pay Level 3 $[REDACTED] within [REDACTED] of execution of the
Agreement.   Thereafter,  Teligent  shall  pay  Level  3  a  "down  payment"  of
[REDACTED]%of  the Total  Wavelength  Fees (as set forth and  calculated  in the
chart above based on a $[REDACTED]charge  [REDACTED]) within thirty (30) days of
the  Acceptance  Date  [REDACTED],  less  [REDACTED]  to offset the  $[REDACTED]
initial payment. [REDACTED]. The foregoing payments will be invoiced by Level 3.
Teligent  also  agrees to pay Level 3  $[REDACTED]  per Route of  Capacity  as a
Non-Recurring  installation charge, which shall be paid by Teligent (on all Ring
Routes) within 30 days of the Acceptance Date [REDACTED].

The  balance  of the Total  Wavelength  Fee shall be paid as a yearly  recurring
charge  (as set forth in the  summary  chart  above)  for the  Wavelengths  Term
[REDACTED]  (subject to the  limitations of Section 8.6).  The yearly  recurring
charge shall be paid in 12 equal monthly  installments,  payable in advance each
month.  The Total  Wavelength  Fees are predicated on a charge of [REDACTED] for
the Wavelength  Term,  and the parties shall  negotiate in good faith to rectify
any mistakes in the calculation of the Total  Wavelength Fee as set forth above.
In addition,  Teligent  shall pay Level 3 the PO & M Charge set out in Article 7
of this Exhibit. Furthermore, it is agreed that this paragraph and the preceding
paragraph shall govern any contradiction in the above tables.

<PAGE>
                                  Appendix "B"
                                      [SLA]

Performance Targets

1.       Credit for outages as follows:

[REDACTED]

Service Unavailability ("SU" or "Unavailability") Event:

[REDACTED]

4.       Minimum Specifications

Furthermore,  it is agreed  that  Unavailability  will occur if Level 3 fails to
meet any of the following minimum set of specifications:

[REDACTED]

5.       Intermittent Unavailabilities

[REDACTED]
<PAGE>
                                  Appendix "C"
                                    Ring Map
                                   [REDACTED]


                                    EXHIBIT 3
                 ADDITIONAL TERMS AND CONDITIONS FOR COLOCATION
                                    RECITALS

         Level 3 owns,  controls or holds leasehold  interests in certain office
and storage  space  ("Gateway(s)")  suitable for the  placement and operation of
communications  equipment  and is willing to grant  Customer the right to occupy
portions of the Gateways (the "Colocation  Space") upon the terms and conditions
hereinafter set forth; and

         Teligent  ("Customer") desires access to the Colocation Space set forth
on  Exhibit  A to place  therein  certain  communications  equipment,  including
interconnecting  such  equipment  with  Level  3's  and  others'  communications
network(s) in order to utilize  Capacity and metro dark fiber as provided  under
the Agreement.

1.       SCOPE

         A. Upon  acceptance  by Level 3 of an Order (as  defined in Section 4.A
below) for Colocation  Space,  Level 3 grants to Customer,  and Customer  hereby
agrees to purchase from Level 3 (in accordance with the terms of this Agreement)
a license  to  occupy  Colocation  Space  designated  by Level 3 in the  Gateway
identified in the Order.  Customer may commence to occupy the  Colocation  Space
upon Level 3's  completion of the build-out of the  Colocation  Space.  Customer
shall use the Colocation  Space for the placement,  operation and maintenance of
electronic  and  optronic  or  other  equipment  used  for the  transmission  of
communications signals ("Equipment") and not for storage (other than the storage
of tools and spare parts for use in maintaining the  Equipment).  Customer shall
be permitted to interconnect,  or cause Level 3 to  interconnect,  the Equipment
with the equipment or networks of Level 3 and other carriers,  including without
limitation,  the dominant local exchange  carrier,  if such other carrier(s) are
colocated in the Gateway and such interconnection is technically feasible.

         B.  Customer  shall be permitted  unescorted  access to the  Colocation
Space seven (7) days per week and twenty-four (24) hours per day, subject to any
and all rules, regulations and access requirements reasonably imposed by Level 3
governing such access. Level 3 warrants that such rules,  regulations and access
requirements  shall not be inconsistent with any of Customer's rights under this
Agreement. Level 3 reserves the right, on ninety (90) days' prior written notice
(except in emergency situations), to change the location or configuration of the
Colocation Space at Level 3's sole cost and expense (which shall be accomplished
only after  consultation with Customer (except in emergency  situations)).  Such
right may be exercised  not more than twice during any calendar  year during the
Term.  Such  new  location  shall  be in the same  Gateway  and be  functionally
equivalent and substantially  similar to the initial  Colocation Space. Such new
configuration shall be functionally  equivalent and substantially similar to the
initial  configuration.  An "emergency"  shall mean an immediate and substantial
threat  of  damage  to  property  or  injury  or  death  to  any  person  or  an
unanticipated  event  affecting  the service for which the  Colocation  Space is
being  used.  Level 3 and  Customer  agree  to work  together  in good  faith to
minimize any disruption of service in connection with such  relocation.  Level 3
reserves the right to access the Colocation  Space for any  legitimate  business
purpose related to the use,  maintenance  and/or  operation of its own equipment
and  facilities in the  Colocation  Space or the Gateway upon  reasonable  prior
notice to Customer.
<PAGE>
C. Customer may not provide or make available any portion of the Colocation
Space to any third party. Any violation of this provision shall be deemed a
material breach of this Agreement.

D. This Exhibit 3 constitutes  Customer's  Order,  which Level 3 hereby accepts,
for the Colocation Spaces identified on Exhibit A at the respective  charges set
forth on Exhibit A. Customer agrees that it shall pay Level 3 the  non-recurring
charges (and shall commence  paying the recurring  charges) for each  Colocation
Space on the date the Term for the Space commences.

2.       DURATION OF TERM

         A. Term.  Unless  otherwise  agreed in an Order, the term of use of the
Colocation  Space  shall  begin on the later to occur of the date  requested  by
Customer  or the date that Level 3 completes  the  build-out  of the  Colocation
Space and shall continue  thereafter for a term coterminous with the term of the
services  (either  wavelengths or dark fiber) for which the Colocation  Space is
being used.  (the "Term").  As to future Orders of  Colocation  Space,  the Term
shall be as set forth in the  Order,  or, in the  event  that an Order  does not
specify a term for the use of Colocation  Space,  the Term shall be one (1) year
from the date that Level 3 completes  the  build-out  of the  Colocation  Space.
After the expiration of the Term, use of the Colocation  Space shall continue on
a month-to-month basis (which shall be terminable by either party on thirty (30)
days' written notice) under the same terms and  conditions,  unless Customer and
Level 3 have  agreed in writing to a specific  term  renewal of the right to use
such Colocation Space.

         B. Upon expiration or termination of Customer's right to use Colocation
Space,  Customer,  at its expense,  shall remove  Equipment  and other  property
(except  cabling,  which Customer may leave at its election) from the Colocation
Space and  return  the  Colocation  Space to Level 3 in  substantially  the same
condition  (reasonable  wear and tear and casualty  excepted)  as when  Customer
first occupied the Colocation  Space.  In the event Customer fails to vacate the
Colocation  Space within twenty (20) days from the  termination or expiration of
the term with respect thereto, Level 3 shall give notice thereof to Customer and
10  business  days  thereafter,  Level 3 shall  have  the  right to  remove  the
Equipment and other  property of Customer at Customer's  expense,  in accordance
with all  applicable  laws,  and Level 3 shall have no  liability  for damage or
injury to Customer's  property  unless caused by the  negligence or  intentional
misconduct of Level 3.

C.  Customer  hereby  agrees to pay for the  Colocation  Space  and any  related
services  described  hereunder and ordered by Customer for the Term.  Subject to
the requirements to pay termination  charges set forth below, by notice to Level
3,  Customer  may for any  reason  terminate  an Order and this  Agreement  with
respect to such Order and the  applicable  Colocation  Space.  In the event that
Customer  terminates  an Order for  Colocation  Space which has been accepted by
Level 3 or in the event that the Order is  terminated  pursuant  to Section  2.D
(2)-(4) below,  Customer shall comply with Section 2.B above,  including without
limitation,  the requirements for returning the Colocation Space and shall pay a
termination charge, which shall constitute liquidated damages and not a penalty,
equal to the  reasonable  and  documented  direct  costs  incurred by Level 3 in
undoing any  improvements to the Colocation  Space made  specifically for and at
Customer's  request,  but only to the extent  necessary to render the Colocation
Space in a condition  suitable for general use by other parties,  plus a portion
of the monthly  recurring  fees for the remainder of the Term following the date
of termination for the terminated Colocation Space, calculated as follows:

[REDACTED]

1.
<PAGE>
         D. In no  event  shall  Customer  pay  termination  charges  for  early
termination  due to Level 3's  material  breach of this  Exhibit.  Additionally,
Customer  may  teminate,  without the payment of any  termination  charges,  any
Colocation  Space which was used by Customer  directly  in  connection  with any
Wavelength  Services  or any  license to use Metro Dark Fiber to the extent that
such services or licenses are terminated by Customer  pursuant to the Wavelength
Services Exhibit or the Metro Dark Fiber Exhibit, either as permitted thereunder
or as a result of a default thereunder by Level 3.

         E. Level 3 shall have the right to  terminate,  upon  [REDACTED]  days'
written notice (or such shorter period of time as specified  below),  Customer's
use of the  Colocation  Space or the  Services in the event that:  (1) Level 3's
right  to use  the  facility  within  which  the  Colocation  Space  is  located
terminates  or expires for any reason (in which  event,  Customer  shall have no
termination  liability  under  Section  2.C or  otherwise,  and  Level  3  shall
immediately  refund all payments Customer has made for the terminated portion of
the Term);  (2) Customer  has violated any material  term hereof or of any Order
submitted  hereunder;  (3)  Customer  makes  any  material  alterations  to  the
Colocation  Space without first  obtaining the written consent of Level 3 (which
shall not be unreasonably withheld); or (4) Customer allows unescorted personnel
to enter the Colocation Space, other than Customer's  personnel,  contractors or
technicians  who have been approved by Level 3 in  accordance  with Section 3.C.
With  respect  to items  (2),  (3) and (4)  immediately  above,  unless the same
materially  interferes or is substantially  likely to materially  interfere with
other Level 3 customers,  Level 3 shall provide Customer a written notice of the
foregoing and a [REDACTED] day  opportunity to cure the same before  terminating
Customer's rights to the Colocation Space.

3.       USE OF COLOCATION SPACE

         A. Customer shall not use the  Colocation  Space for marketing or other
general  office  purposes.  Customer shall place no signs or marking of any kind
(except  for a plaque  or other  identification  affixed  to the  Equipment  and
reasonably necessary to identify the Equipment and which shall include a list of
emergency  contacts  with  telephone  numbers) in the Gateway or the  Colocation
Space.

         B.  Except  as  otherwise  provided  in this  Agreement  or any  Order,
Customer  is  solely   responsible   for  the  design,   engineering,   testing,
performance, monitoring, maintenance, and repair of the Equipment and facilities
used by Customer in the Colocation Space.

         C. Customer shall abide by any posted or communicated (by notice) rules
relating to use of, access to, or security  measures  respecting  the Colocation
Space,  provided such rules are not  inconsistent  with Customer's  rights under
this  Agreement.  Customer may bring its customers into the Colocation  Space in
compliance with Level 3's policies respecting such access.  Customer may request
access  to  the  Colocation  Space  for  any of its  personnel,  contractors  or
technicians by contacting Level 3's Customer Care Department (877-4-LEVEL3).  In
the event  Customer  or any of its agents or  employees  is found in the Gateway
with any firearms, drugs, alcohol or is found engaging in any criminal activity,
eavesdropping,  foreign  intelligence,  card selling or slamming,  Level 3 shall
have the right to require  that such  employee or agent  immediately  vacate the
facilities  and such  employee or agent  shall not be allowed to return.  In the
event that  unauthorized  parties gain access to the  Colocation  Space  through
access cards, keys or other access devices provided to Customer,  Customer shall
be responsible for any damages  incurred as a result thereof.  Customer shall be
responsible for the cost of replacing any security  devices lost or stolen after
delivery thereof to Customer.
<PAGE>
         D.  Notwithstanding  any other provisions of this Agreement,  Equipment
and  facilities  placed  in the  Colocation  Space  by  Customer  shall  not (a)
interfere  with or impair  service  provided  by Level 3 or by any  other  party
located in the Gateway;  (b) endanger or damage the  facilities of Level 3 or of
any other party,  the  Colocation  Space,  or the Gateway;  (c)  compromise  the
privacy of any communications  carried in, from, or through the Gateway;  or (d)
create  an  unreasonable  risk of injury  or death to any  individual  or to the
public. If Level 3 determines,  in its reasonable  business  judgment,  that any
Equipment  or  other  property  of  Customer  violates  the  provisions  of this
paragraph,  Level 3 shall  give  written  notice  to  Customer  specifying  such
violations in detail,  which notice shall direct  Customer to cure the violation
within  twenty-four (24) hours or, at a minimum,  to commence  curative measures
within twenty-four (24) hours and to exercise  reasonable  diligence to complete
such measures as soon as possible thereafter. If Customer fails to take curative
action within twenty-four (24) hours or if the violation is of a character which
poses an immediate and substantial threat of damage to property, injury or death
to any person, or interference/impairment of the services provided by Level 3 or
its  customers,  then Level 3 may take such  action as it deems  appropriate  to
correct  the  violation,  including  without  limitation,  the  interruption  of
electrical power to Equipment.  Level 3 will provide notice to Customer prior to
taking  such  action and shall have no  liability  to  Customer  for any damages
arising from such action.

4.       ORDERING AND PREPARATION OF COLOCATION SPACE

         A.  Submission of Additional  Orders.  Except for the Colocation  Space
ordered pursuant to Section 1(D),  Customer shall request  Colocation Space from
Level 3 by submitting a written order ("Order") (prepared with the assistance of
Level 3 and on a form  specified by Level 3) for such  Colocation  Space setting
forth the  location of the Gateway  facility  within which  Colocation  Space is
requested  and  the  recurring  and  non-recurring  charges  applicable  to  the
Colocation  Space.  Level 3's delivery of a target install date shall constitute
Level 3's acceptance of Customer's Order.

         B. Installation and Build-Out. Level 3 shall use all reasonable efforts
to complete  the  build-out  and make the  Colocation  Space listed in Exhibit A
available  to Customer on or before the date  requested  by  Customer.  Customer
agrees that it shall accept delivery of and commence paying for Colocation Space
in  advance of the date  Customer  has  requested  if such  Colocation  Space is
tendered by Level 3 and delivered in accordance with this Agreement. [REDACTED]
<PAGE>
         C.  Acceptance.  Customer  shall have  [REDACTED]  business  days after
written  notification by Level 3 that build-out is completed in which to inspect
the Colocation Space and verify that it is in compliance with the specifications
set forth in Exhibit B or the  applicable  Order,  or  provide  Level 3 with its
written  rejection  of such  Colocation  Space,  in which  event,  Level 3 shall
commence to bring the Colocation Space into compliance with such specifications.
If  Level 3 fails  to  bring  the  Colocation  Space  into  compliance  with the
specifications  within  [REDACTED]  days  after  Customer's  rejection  thereof,
Customer,  in its sole discretion,  may terminate this Agreement with respect to
such  Colocation  Space  and  receive  a refund  of any fees paid for the use or
build-out of such Colocation Space.

5.       RATES AND CHARGES

The monthly  recurring  charges and  nonrecurring  charges for Colocation  Space
initially ordered hereunder are set forth in Exhibit A.

6.       MAINTENANCE OF GATEWAYS

         Level 3 shall perform such janitorial services,  environmental  systems
maintenance,  power  plant  maintenance  and  other  actions  as are  reasonably
required to maintain the Gateway in which the  Colocation  Space is located in a
condition which is suitable for the placement of telecommunications and internet
access equipment.

[REDACTED]

         EXCEPT AS EXPRESSLY STATED HEREIN OR IN ANY ORDER, THE COLOCATION SPACE
SHALL BE DELIVERED AND ACCEPTED "AS IS" BY CUSTOMER,  AND NO REPRESENTATION  HAS
BEEN MADE BY LEVEL 3 AS TO THE FITNESS OF THE  COLOCATION  SPACE FOR  CUSTOMER'S
INTENDED PURPOSE.

7.       [INTENTIONALLY DELETED]

8.       MECHANIC'S LIENS

No mechanic's lien or other liens shall be filed against property of Level 3, or
any improvement  thereon,  by reason of or arising out of any labor or materials
furnished, alleged to have been furnished, or to be furnished to or for Customer
or by reason of any change or addition to property  made at the request or under
the direction of the Customer.  If such a lien shall be filed,  Customer  shall,
within thirty (30) days after receipt of written notice from Level 3, either pay
such lien or cause the same to be bonded  off Level 3's  property  in the manner
provided by law. Customer shall also defend, on behalf of Level 3, at Customer's
sole cost and expense,  any action,  suit or proceeding which may be brought for
the  enforcement  of such liens and Customer  shall pay any damage and discharge
any judgment entered thereon.
<PAGE>
9.       INSPECTIONS

Level 3 shall conduct an inspection of Customer's  Equipment and other  property
in the  Colocation  Space(s)  prior  to the  activation  of  facilities  between
Customer's  Equipment and equipment of Level 3. Such inspections shall determine
compliance with the performance,  quality, environmental and safety requirements
developed by Bellcore for equipment and materials,  all as set forth in Bellcore
TR-NWT-000063,  issue 4 and a  minimum  of GR63  level  2  support.  Level 3 may
conduct an  inspection if Customer  adds  Equipment  and may  otherwise  conduct
routine inspections at reasonable intervals mutually agreed upon by the parties.
Level 3 shall provide  Customer with a minimum of forty-eight  (48) hours or two
(2) business days, whichever is greater, advance notice of all such inspections.

10.      REMOTE HANDS

Customer may order and pay for Level 3 to perform certain limited "remote hands"
maintenance  services on Equipment within the Colocation  Space,  which shall be
performed in accordance with Customer's  directions.  "Remote hands" maintenance
services  includes  power  cycling  Equipment.  Level 3  shall  in no  event  be
responsible  for the  repair,  configuration  or  tuning  of  Equipment,  or for
installation of Equipment  (although Level 3 may provide  assistance to Customer
in such installation).

11.      [INTENTIONALLY DELETED]

12.      [INTENTIONALLY DELETED]

13.      DESTRUCTION OF COLOCATION SPACE

In the  event a  Colocation  Space  is  wholly  or  partially  damaged  by fire,
windstorm,  tornado,  flood or by  similar  causes  to such an  extent  as to be
rendered wholly unsuitable for Customer's  permitted use hereunder,  then either
party may elect  within ten (10) days  after  such  damage,  to  terminate  this
Agreement  by giving the other  written  notice of  termination  (in which event
Customer shall have no termination liability under Section 2.C or otherwise). If
either  party  shall so elect,  both  parties  shall be  released  from  further
liability for such  Colocation  Space under the terms hereof.  If the Colocation
Space shall suffer only minor damage and shall not be rendered wholly unsuitable
for  Customer's  permitted use, or is damaged and the option to terminate is not
exercised  by either  party,  Level 3 covenants  and agrees to proceed  promptly
without expense to Customer,  to repair the damage except for  improvements  not
the  property of Level 3. Level 3 shall have a  reasonable  time within which to
rebuild or make any repairs,  and such rebuilding and repairing shall be subject
to delays  caused  by  storms,  shortages  of labor  and  materials,  government
regulations,  strikes, walkouts, and causes beyond the control of Level 3, which
causes shall not be construed as limiting  factors,  but as examples only. Where
allowed and where  practical in the sole judgment of Level 3, Customer may erect
a temporary facility while Level 3 rebuilds or makes repairs. In all cases where
the Colocation Space shall be rebuilt or repaired, Customer shall be entitled to
an  equitable  abatement of charges,  depending  upon the  unsuitability  of the
Colocation  Space for Customer's  permitted use, until such Colocation  Space is
fully repaired and restored and Customer's  Equipment  installed therein (but in
no event  later  than  thirty  (30)  days  after the  Colocation  Space is fully
repaired and restored).
<PAGE>
14.      EMINENT DOMAIN

Level 3 shall  provide  Customer  with as much written  notice as is  reasonably
possible  after Level 3 has been  informed  that its rights to use the  facility
will be taken by any public authority under the power of eminent domain.  If the
whole of a  Colocation  Space shall be taken by any public  authority  under the
power of eminent domain,  then Customer's  rights to such Colocation Space shall
terminate as of the day possession  shall be taken by such public  authority and
rent and other  charges  for the  Colocation  Space shall be paid up to that day
with a proportionate refund by Level 3 of such rent and charges as may have been
paid in advance for a period  subsequent to the date of the taking (and in which
event  Customer  shall  have  no  termination  liability  under  Section  2.C or
otherwise).  If any part of a  Colocation  Space  shall be taken  under  eminent
domain,  Level 3 and  Customer  shall  each  have the  right to  terminate  this
Agreement  with respect to such  Colocation  Space and declare the same null and
void,  by written  notice of such  intention  to the other Party within ten (10)
days after such taking (and in which event  Customer  shall have no  termination
liability under Section 2.C or otherwise).  With respect to any Colocation Space
the use of which has been  terminated in  accordance  with this Section 14, both
parties shall be released from further liability for such Colocation Space under
the terms hereof.

15.      [INTENTIONALLY DELETED]

16.      [INTENTIONALLY DELETED]

17.      NONEXCLUSIVITY

Each party  understands  that this Agreement is not exclusive and that the other
party may enter into similar agreements with third parties. Level 3 shall not be
obligated to reserve  Colocation  Space in any Gateway for  Customer  unless and
until an Order is submitted to and accepted by Level 3.

18.      [INTENTIONALLY DELETED]

19.      [INTENTIONALLY DELETED]

20.      [INTENTIONALLY DELETED]

21.      SUBORDINATION

In the event the Gateway or Colocation Space is leased by or otherwise  provided
to Level 3 pursuant to a written  agreement,  the terms and  conditions  of this
Agreement  shall be  subordinate  to the terms and  conditions  of said  written
agreement regarding the use and access of the Gateway or Colocation Space. In no
event shall Level 3 be required to provide Customer any rights to the Gateway or
Colocation Space greater than those rights and obligations held by Level 3.

22.      [INTENTIONALLY DELETED]
<PAGE>
                                    EXHIBIT A
                            INITIAL COLOCATION SPACE
                                      ORDER

--------------------------------------------------------------------------------
 #    City            Facility     Space (SF) /Rack   SF Required     Customer
                        Type         Requirement                   Request Date
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
   [REDACTED]        [REDACTED]       [REDACTED]       [REDACTED]    [REDACTED]
--------------------------------------------------------------------------------
<PAGE>
                                    EXHIBIT B

SPECIFICATIONS

The following section delineates the general  specifications for Level 3 Gateway
facilities.  Level 3 may deviate  from the  specifications  set forth  herein in
those  instances  where  either  (i) strict  compliance  is  impractical  due to
physical  (including  environmental)  conditions,  right-of-way  issues  or code
restrictions, or (ii) Level 3 has acquired the property from a third party.

Level 3 will  construct  facilities,  to house DC power  plants and the  telecom
infrastructure  for the  installation  and operation of electronic  and optronic
equipment.

Access  to the  Colocation  Space  will  be via a  separate  entrance  into  the
facilities from the outside, which will be secured twenty-four (24) hours a day.
The facilities will be equipped with a minimum of 200amp 120/208 volt electrical
services.

The  following  are the general  specifications  of the  facilities  and support
equipment to be provided by Level 3:

Facilities will be equipped with air conditioning  units and shall be maintained
at an average room  temperature  between fifty (50) and eighty-five (85) degrees
Fahrenheit.  There will be a minimum of two (2) units installed at each facility
for HVAC redundancy.

The facility sites will be equipped with a backup generator.  The generator fuel
tanks will have  approximately  twenty-four (24) hour fuel capacity.  As part of
the normal  maintenance,  the  generator  will be exercised on a monthly  basis,
running on a load bank for a minimum of fifteen (15)  minutes.  There will be an
Automatic  Transfer  Switch for the  automatic  start-up of the generator in the
event of a primary power loss.

Fire extinguishers will be provided within the facilities.

The facilities will have grounding system  termination bars terminated to either
the main electrical system ground and /or driven ground rod.

The  facilities  will be  equipped  with AC  duplex  isolated  outlets  for test
equipment  and  miscellaneous  use. Such outlets will be placed as needed around
each facility.

The  facilities  will have  sufficient  lighting on the interiors as well as the
exteriors.

Level 3 will not be responsible  for  installation  in the  Colocation  Space of
relay racks,  but will install a single tier 12" ladder rack system.  The ladder
rack will be used for DC power  distribution  and with attached  angle clips for
signal cable distribution.

Level 3 will  provide DC power  providing  negative 48 volts with an "A" and "B"
feed to Customer's racks,  cabinets or equipment within the Level 3 facility for
Customer's  use. The DC power plant will also be equipped  with a battery  plant
designed to provide at least two (2) hours of reserve time.  The battery  plants
will  incorporate  load  disconnects  and  batteries  capable of  recharging  in
twenty-four (24) hours.

The fiber  cable  through  the  facility  will enter and exit within the Level 3
facility. Fiber will be brought over to the Colocation Space via a fiber guide.
<PAGE>
All entry and exits and  environmental  systems will be monitored  remotely on a
twenty-four (24) hour basis.

Customer will monitor its own electronic and optronic equipment.
<PAGE>
                                    EXHIBIT 4
                       ADDITIONAL STRATEGIC OPPORTUNITIES

The parties agree to discuss in good faith the following additional strategic
opportunities

                                   [REDACTED]
<PAGE>



                        ADDENDUM TO MAY 9, 2000 AGREEMENT
                       BETWEEN LEVEL 3 COMMUNICATIONS, LLC
                           AND TELIGENT SERVICES, INC.

         This addendum ("Addendum") is made and entered into as of this 21st day
of July,  2000, by and between Level 3  Communications,  LLC, a Delaware limited
liability  company  ("Level  3")  and  Teligent   Services,   Inc.,  a  Delaware
corporation ("Teligent").  This is an Addendum to that certain Agreement between
the parties  made and  entered  into as of May 9, 2000 and  specifically,  is an
Addendum  to  Exhibit  1  to  that  Agreement  entitled  "Additional  Terms  and
Conditions Governing Metro Dark Fiber" (the "Metro Dark Fiber Agreement").

                                    RECITALS

         A. The Metro Dark Fiber Agreement  [REDACTED] to Level 3 by Teligent
for Teligent's  [REDACTED] use the Metro Dark Fiber identified therein.
[REDACTED] on the terms and conditions set forth in this Addendum.

         B. Level 3 and Teligent wish to correct  certain  typographical  errors
contained  within the Metro Dark Fiber  Agreement and to otherwise  modify it as
necessary considering Teligent's agreement to [REDACTED].

NOW THEREFORE the parties mutually agree to amend the Metro Dark Fiber Agreement
in the following respects:

         1.  Section 2.01 of the Metro Dark Fiber Agreement is deleted and
             replaced with the following provision:
<PAGE>
         The Grantor  System will connect the points  identified  on Exhibit "A"
         attached hereto (each point  identified on Exhibit "A" is herein called
         a "Segment End Point",  the route  between the  applicable  Segment End
         Points is herein called a "Segment",  and all of the Segments  together
         are herein called the "System Route").  The Grantor System will include
         the  "Lateral  Segments,"  if  any,  identified  in  Exhibit  "A".  The
         cumulative  Route Miles for all Segments ordered by grantee pursuant to
         this Agreement  (excluding  Lateral  Segments) are  [REDACTED]  Grantee
         Fibers within each Segment,  so that the total fiber miles (Route Miles
         times  the   number  of  fibers)   initially   ordered  by  Grantee  is
         [REDACTED]). Grantee further agrees to purchase a [REDACTED] additional
         Grantee Fibers from all of the Segments  listed in Exhibit "G" when the
         same are  available for delivery by Level 3,  bringing  Grantees  total
         fiber miles to [REDACTED].  Grantee further agrees to purchase,  within
         six  (6)  months  of the  date of  signing  the  Agreement,  additional
         available fiber  (excluding the fiber contained in any Lateral Segment)
         so that the total  fiber  mileage for Grantee  Fibers  hereunder  is at
         least [REDACTED]  miles (the "Minimum  Purchase  Commitment").  Grantee
         shall inform Grantor,  in writing,  of the number of additional Grantee
         Fibers within six (6) months from the date of this  Agreement.  Grantee
         may  satisfy  the  Minimum  Purchase  Commitment  only by purchase of a
         license in entire Segments (partial Segments may not be purchased).  In
         the event  Grantee  does not  inform  Grantor  of the number of Grantee
         Fibers  desired  necessary to satisfy the Minimum  Purchase  Commitment
         within the time frames set forth herein,  then Grantee shall be charged
         for that unsatisfied  portion of the Minimum Purchase Commitment as set
         forth in Exhibit "B" (even  though  Grantee did not satisfy the Minimum
         Purchase Commitment). [REDACTED]

         [REDACTED]

         2.       Section 4.01 of the Metro Dark Fiber Agreement is deleted and
replaced with the following provision:

         4.01 Grantee agrees to pay, as compensation  for Grantor's  performance
         of incremental  design,  engineering,  planning and  development of the
         Grantee Fibers (including but not limited to the Lateral Segments), the
         design, planning and engineering fee set forth in Exhibit "B".

         3.       Section 4.05 of the Metro Dark Fiber Agreement is deleted and
replaced with the following provision:

         4.05 Grantor will send Grantee  invoices for the License Fee (set forth
         in  Exhibit  "B")  and  Grantee  shall  pay  such  invoice  amounts  in
         accordance with the Agreement, [REDACTED].

         4.       In Section 5.01 of the Metro Dark Fiber Agreement is deleted
and replaced with the following provision:

         5.01 The [REDACTED]with  respect to each Segment shall become effective
         on the first day when both (i) the Acceptance  Date with respect to the
         Grantee  Fiber  within a Segment  has  occurred  and (ii)  Grantor  has
         received  payment of all fees and charges  attributable to such Segment
         which are due under this Exhibit  [REDACTED]  (the  "Effective  Date").
         Subject to the provisions of Article 20, the [REDACTED] with respect to
         the Grantee Fibers within each Segment shall terminate on the twentieth
         (20th) anniversary of the Effective Date (the "Term").

         5.  Section  10.01 of the Metro Dark Fiber  Agreement  is  modified  by
adding   the  words  "and   Grantor   shall   thereafter   agree  to  make  such
interconnections  of, subject to the terms of this Agreement"  immediately after
the phrase "request that the Grantor interconnect".
<PAGE>
         6.       Article 17 of the Metro Dark Fiber  Agreement  is modified by
adding  thereto an  introductory  paragraph  reading as follows:

         [REDACTED]

         7. The  second  sentence  of  paragraph  20.03 of the Metro  Dark Fiber
Agreement is modified by deleting the phrase  "shall have the right to terminate
this  Agreement"  and  replacing  it with the  phrase  "shall  have the right to
terminate the affected Segment."

         8.       Exhibit "A" to the Metro Dark Fiber  Agreement  is deleted in
its  entirety  and  replaced  with Exhibit "A" attached hereto.

         9.       Exhibit "B" Metro Dark Fiber Agreement is deleted and replaced
with Exhibit "B" attached hereto.


TELIGENT ("GRANTEE") ACCEPTANCE        LEVEL 3 ("GRANTOR") ACCEPTANCE

-------------------------------------  -----------------------------------------
Authorized Customer Signature          Authorized Level 3 Signature

-------------------------------------  -----------------------------------------
Date                                   Date

-------------------------------------  -----------------------------------------
Typed or Printed Name                  Typed or Printed Name

-------------------------------------  -----------------------------------------
Title                                  Title
<PAGE>
                                   Exhibit "A"
               Segment Descriptions and Scheduled Completion Dates

[REDACTED]

o    For  all Segments  listed as complete,  the Scheduled  Completion  Date
shall be 90 days from the execution of the Agreement.

3.       Lateral Segment Descriptions.

[REDACTED]

3.       Segment End Points for Lateral Segments

         a. For Targeted  Lateral  Segments  which are  connecting  the backbone
network to local exchange carrier central offices ("LEC CO's"),  the Segment End
Point for the Grantee Fiber will be at Grantor's OSX within the LEC CO.  Grantor
shall be responsible  for bringing its fiber to such Segment End Point,  and for
securing any and all agreements,  consents,  permissions or authorizations  from
the LEC.

         b. For Targeted  Lateral  Segments  which are  connecting  the backbone
network to locations  other than LEC CO's, the Segment End Point for the Grantee
Fiber will be at Grantor's  OSX panel in or  contiguous  to  Grantor's  point of
presence  within the  building.  Grantee shall be  responsible  for bringing its
fiber to such  Segment  End  Point,  and for  securing  any and all  agreements,
consents,  permissions  or  authorizations  from the  building  owner or manager
necessary to install such connecting fiber.

         c.  For  Non-Targeted  Lateral  Segments  to which  laterals  are to be
constructed  as agreed to between the parties,  the Segment End Point will be as
negotiated and priced between the parties.

         d.  [Intentionally Deleted]

         e.  [Intentionally deleted]
         f.  Any work required  to connect the  Grantee  Fibers to other  fibers
owned or  procured  by Grantee  (including,  but not  limited  to,  coring  into
Grantor's  manholes,  hand holes or points of  presence)  shall be  performed by
Grantor pursuant to Section 10.03 of the Agreement.
<PAGE>
                                   Exhibit "B"
                                      Fees

A.   License Fee for Segments.

The total  License Fee for the  Grantee  Fibers  meeting  the  Minimum  Purchase
Commitment  (excluding the Lateral  Segments) is  [REDACTED].  Grantee shall pay
Grantor  [REDACTED]  of such total  [REDACTED]  Fee within  thirty  (30) days of
delivery  by Grantor  of an  invoice  for such  amount  delivered  upon or after
execution of this  Amendment,  such amount  representing a design,  planning and
engineering fee. The remaining  [REDACTED] of such total [REDACTED] Fee shall be
broken down on a Segment by Segment  basis and payable by Grantee  [REDACTED] on
the Acceptance Date for such Segment [REDACTED]  invoiced at least 30 days prior
to the due date of the invoice.

         [REDACTED]

         In the event Grantee fails to order additional fibers necessary to meet
Grantee's Minimum Purchase Commitment,  Grantee shall pay Grantor the [REDACTED]
of the total  [REDACTED]Fee  allocable  to those  fibers not  ordered by Grantee
within 30 days of Grantee's  receipt of an invoice  therefore  delivered upon or
after  expiration of the six (6) month period in which Grantee has to order such
additional  fibers.  Grantee may, however,  thereafter place orders with Level 3
and accept fibers in satisfaction of Grantee's Minimum Purchase Commitment.

C.       Lateral Segment Fees.

The Lateral  Segments  Identified in Exhibit "A" shall be paid for by Grantee as
set forth below:

A design,  planning  and  engineering  fee  (designated  as a "down  payment" in
Exhibit "A" on a Lateral  Segment by Lateral Segment basis) of [REDACTED] of the
total of the estimated  Lateral  Segment Fee's  [REDACTED] for a down payment of
[REDACTED].  This design,  planning and engineering fee shall be paid by Grantee
within  thirty (30) days of execution of the  Agreement and Grantor will invoice
Grantee  accordingly.  Within thirty (30) days of the  Acceptance  Date for each
Lateral  Segment,  Grantee  will  pay  Grantor  for  such  Lateral  Segments  in
accordance  with the  percentages  set  forth  below,  minus  the  down  payment
previously paid by Grantee for the subject Lateral Segment.

         For Targeted Lateral Segments

         Payment:  For the Targeted  Lateral  Segments  listed on Exhibit "A" or
         classified as Targeted  Lateral  Segments under Article 8, Grantee will
         reimburse Grantor [REDACTED] incurred by Grantor in connection with the
         construction   and  installation  of  such  Targeted  Lateral  Segment,
         [REDACTED].

         For Non-Targeted Lateral Segments

         Payment: For the Non-Targeted Lateral Segments listed on Exhibit "A" or
         classified as  Non-Targeted  Lateral  Segments under Article 8, Grantee
         will  reimburse  Grantor  [REDACTED]  incurred by Grantor in connection
         with the  construction and  installation of such  Non-Targeted  Lateral
         Segment, [REDACTED].

Any additional  Lateral Segments  requested by Grantee will be priced by Level 3
as set forth above,  and subject to payment by Grantee in the same manner as set
forth above.

[REDACTED]

3.       General

[REDACTED]

Slack Fiber

In the event any  Lateral  Segment  (other  than those  listed in  Exhibit  "A")
requires the delivery of slack fiber,  Grantee shall be responsible  for 100% of
the  Costs  associated  with  supplying  slack  fiber for  Grantee's  use in any
manhole.  Grantee shall reimburse Grantor for such Costs within thirty (30) days
after delivery of an invoice for such Costs.