<PAGE>

                                                                   Exhibit 10.20

                           MASTER SERVICES AGREEMENT


                                      FOR


                            MONITORING AND SERVICES


                                    BETWEEN


                             GTE NETWORK SERVICES


                                      AND


                        GTE GLOBAL NETWORKS CORPORATION



                           MASTER SERVICES AGREEMENT
<PAGE>

                                                                   EXHIBIT 10.20

                           MASTER SERVICES AGREEMENT

This Master Services Agreement ("Agreement"), is made effective as of
__________, 1999, by and between GTE Network Services consisting of the GTE
Telephone Operating Companies listed on Attachment A ("GTE") and GTE Global
Networks Corporation ("GNI").


1.0  Scope

GTE will provide, through its Network Operations Center ("NOC"), network
monitoring of network enabling devices and processes twenty four (24) hours a
day, seven (7) days a week, three hundred sixty-five (365) days a year to
detect, escalate, restore, and follow-up on anomalies occurring in the network.
In addition, GTE will provide technical support to GNI for problems that cannot
be resolved on-site; these support services include network element event
problem resolution, network element reliability analysis and network traffic
management.  Exhibit A further explains the aforementioned services.

2.0  Professional Services

GNI retains GTE to perform the services described in Exhibit A and the
Statement(s) of Work, attached hereto and made a part hereof ("Services").  The
Services shall be performed in accordance with the requirements set out in the
Statements of Work.

3.0  Statements of Work

During the Term (hereinafter defined), GNI and GTE (hereinafter referred to
collectively as "Parties" and individually as a "Party") may from time to time
enter into additional statements of work (a "Statement of Work" or "SOW")
defining additional services to be performed by GTE for GNI pursuant to this
Agreement.  Each such Statement of Work shall be added hereto by means of a
written  description of the Services shall contain terms and conditions
supplementing the terms and conditions of this Agreement to the extent the
Parties deem it necessary and defining (i) the Services to which it pertains,
(ii) all work product and other tangible embodiments or results of the
identified Services ("Deliverables"), (iii) delivery dates, (iv) specific
acceptance criteria for Deliverables, and (v) specific price and payment
provisions (if different from or additional to those established in Sections 5,
and 6 of this Agreement).  The scope of the Services set out in Exhibit A and
the Statement(s) of Work may be modified by the authorized representatives of
the Parties.  GTE shall perform no services outside the scope of any Statement
of Work except as otherwise agreed to in writing signed by the Parties.  No oral
changes to the scope of any Statement of Work shall be permitted.
<PAGE>

4.0  Term and Termination

4.1  This Agreement shall be effective upon the execution by both GNI and GTE as
     of the date set forth above, and shall have full force and effect until
     October 31, 2000 unless earlier terminated as provided herein. This
     Agreement may not be renewed.

4.2  Notwithstanding anything to the contrary contained in this Agreement,
     either Party may terminate this Agreement without cause upon providing at
     least ninety (90) calendar days' prior written notice of termination to the
     other Party.

4.3  Notwithstanding Section 4, Term of Agreement, the term of this Agreement
     and the other conditions hereof, are subject to applicable law and
     regulator approval. Accordingly, although the Agreement is executed by both
     Parties, to the extent that any state statute, order, rule or regulation or
     any state regulatory agency having competent jurisdiction over one or both
     of Parties to this Agreement, shall require that this Agreement be filed
     with or approved by such regulatory agency before the Agreement may be
     effective, this Agreement shall not be effective in such state until the
     first business day after such approval or filing shall have occurred.


5.0  Fees

5.1  GNI will pay GTE fees for Services performed and accepted by GNI as set
     forth in the applicable SOW.

5.2  Fees will be paid in accordance with the procedures set forth in Section 6,
     Billing Procedure, below.

5.3  Notwithstanding anything to the contrary contained in this Agreement, Fees
     are at all times subject to review and modification to conform with any
     applicable regulatory requirement governing transactions between GTE and
     its affiliates, including without limitation to FCC Docket 96-150.
<PAGE>

6.0  Billing Procedure

6.1  GTE shall bill GNI each month for the previous month's usage.  GTE shall
     include with the monthly invoice such data GTE and GNI mutually agree is
     necessary for GNI to verify the accuracy of the billing it receives.
     Payment to GTE for bills rendered to GNI shall be due thirty (30) calendar
     days after receipt of the invoice.  Beginning the day after the due date of
     the bill, interest charges of 0.000454 compounded daily or the maximum
     allowed by law, whichever is less, shall be added to GNI's bill.  Payments
     shall be applied to the oldest outstanding amounts first.

6.2  Price Changes.  The rates and charges shall remain in effect and are firm
     for a period of twelve (12) months from the effective date of this
     Agreement, except with respect to any tariff pricing changes or adjustments
     that may occur pursuant to this Agreement or any Statements of Work hereto.
     Thereafter, GTE shall give GNI sixty (60) calendar days' notice of any
     price change.  If the new prices are not acceptable to GNI, GNI may
     terminate this Agreement upon thirty (30) calendar days' notice of any
     price change without penalties for either Party.

6.3  Right to Dispute. GNI shall have the right to dispute any amount so
     invoiced and paid and must notify GTE in writing of any dispute within
     sixty (60) calendar days of the receipt of such invoice or the dispute
     shall be waived. GNI documentation supporting GNI's claim shall be
     forwarded to GTE with the letter of dispute.
     Adjustments.

6.4  Any adjustments relating to a disputed amount shall be reflected on the
     next invoice issued after resolution.  If the dispute is resolved in favor
     of GNI, in whole or in part, GNI shall be entitled to interest of 0.000454
     compounded daily or maximum allowed by law, whichever is less, from GTE to
     the extent the claim is sustained.

6.5  Dispute Resolution.  Disputes between GNI and GTE with respect to this
     Agreement shall be settled in accordance with the provisions set forth in
     Article 18, Dispute Resolution.


7.0  Performance Standards

GTE shall perform the Services with the degree of skill and care that is
required by applicable, generally accepted professional procedures, practices
and standards in the industry so as to ensure that the Services performed and
Deliverables provided meet the requirements of, and are correct and appropriate
for, the purposes contemplated in this Agreement and the applicable Statement of
Work.
<PAGE>

8.0  Performance Schedule

Performance shall begin upon execution of this Agreement.  The Parties will
mutually agree upon any additional performance milestones, meetings or
conferences.


9.0  Direction and Control

Unless otherwise specified in the applicable Statement of Work, GNI shall not
direct, control or supervise GTE as to the details or means by which the
Services are accomplished.  GTE shall be free at all times to arrange the time
and manner of performance of Services and will not be expected to maintain a GNI
established schedule of duties or assignments except as needed to meet
milestones, deadlines or schedules established by the Parties.


10.0 Independent Contractor

10.1 The Parties agree that each Party is engaged in a business which is
     independent from that of the other Party, and each Party shall perform its
     obligation as an independent contractor and not as an agent, employee or
     servant of the other Party.

10.2 Neither Party nor any person furnished by such Party shall be deemed
     employees, agents or servants of the other Party, or be entitled to any
     benefits available under the plans for such other Party's employees.

10.3 Each Party retains the right to exercise full control and supervision over
     its own performance of the obligations under this Agreement and retains
     full control over the employment, direction, compensation and discharge of
     all employees assisting in the performance of such obligations; each Party
     will be solely responsible for all matter relating to payment of such
     employees, including compliance with social security taxes, withholding
     taxes and all other regulations governing such matters; and each Party will
     be responsible for its own acts and those of its own subordinates,
     employees, agents and subcontractors during the performance of that Party's
     obligations.


11.0 Taxes

GNI shall be liable and shall reimburse GTE for payments of federal
manufacturers' and retailers' excise taxes and for payments of federal, state
and local sales, use or similar taxes, as applicable, with respect to
transactions under
<PAGE>

this Agreement, provided such taxes are separately stated in GTE's invoices; it
being understood and agreed that GNI shall have no liability for any taxes not
separately invoiced to GNI. GNI shall not be liable for any tax for which a
valid exemption certificate acceptable to the applicable taxing authorities is
furnished by GNI to GTE. GTE shall be solely responsible for arranging
withholding and payment of all required taxes arising out of GTE's activities in
accordance with this Agreement, including without limitation, federal and state
income taxes, social security taxes, unemployment insurance taxes, and any other
taxes or business license fees related to GTE's business and its directors,
officers, employees, contractors, consultants, or agents. GTE agrees to
indemnify GNI for any and all sums that are due and owing for withholding FICA
and unemployment or other state and federal taxes.

12.0 Assignment

Any assignment of any right, obligations or duty, in whole or in part, or of any
other interest by either Party under this Agreement made without the written
consent of the other Party shall be null and void, except that either Party may
assign this Agreement, in whole or in part, to an affiliate or to the parent
corporation of that Party without consent but upon prior written notice to the
other Party.  Notwithstanding the foregoing, either party may assign this
Agreement without such consent to any affiliate or to any entity that is a
successor to that party by merger or consolidation or that acquires
substantially all of that party's business or assets.


13.0 Confidential and Proprietary Information

13.1 To the extent required to provide and receive services pursuant to this
     Agreement, one Party ("the disclosing Party") may provide and the other
     Party ("the receiving Party") may receive or have access to records and
     information that the disclosing Party considers to be confidential or
     proprietary, including technical information such as specifications,
     drawings, guidelines, models, and other information.  Such information
     shall be marked by the disclosing Party as confidential or proprietary and
     the receiving Party shall hold such confidential or proprietary information
     in trust and confidence for the disclosing Party; shall use it only for the
     purposes permitted hereunder except as may be otherwise agreed to by the
     disclosing Party; and shall deliver to the disclosing Party all such
     records and information upon termination or expiration of this Agreement.
     Nothing in this Article shall be construed to limit the use of or
     dissemination by the receiving Party of such information which was
     previously known to the receiving Party or is or becomes public information
     by means other than disclosure by the receiving Party.
<PAGE>

13.2 The Parties acknowledge that this Agreement constitutes the Proprietary
     information of both Parties and is subject to the terms of this section;
     provided, however that the Parties further acknowledge that this Agreement
     may be filed with any regulatory commission having authority over the
     subject matter, and the Parties agree to seek commercial confidential
     status for this Agreement with any such regulatory commission, to the
     extent such a designation could be secured.


14.0 Title

Except as may otherwise be provided in a SOW to this Agreement, title to the
software programs, database software, hardware, network monitoring or enabling
devices, Services and any products or equipment used in connection with the
Services ("Products"), used or created for GNI hereunder, shall at all times
remain with GTE.  GNI has no property rights in such software programs, database
software, hardware, devises, Services or Products.


15.0 Warranties

15.1 Contractor warrants that any Products, hardware or equipment provided will
     be in working order on the day installed, will be certified by GTE as ready
     for use, and will conform to the functional specifications set out in the
     applicable SOW and to any applicable published Contractor specifications.
     Thereafter, Contractor will make such adjustments, repairs, and replacement
     as necessary to maintain such Products, hardware or equipment in good
     working order pursuant to such specifications.

15.2 In addition, GTE warrants that all Services provided to GNI will be
     performed in a fully workmanlike manner and in accordance with the
     prevailing professional standards of the industry.

15.3 THE FOREGOING WARRANTIES ARE IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR
     IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

15.4 The foregoing warranties shall survive inspection, testing, acceptance, and
     payment.
<PAGE>

16.0 Indemnification

Subject to the limitations contained in this Agreement and to the extent not
prohibited by law, each Party (Indemnifying Party) shall indemnify and hold
harmless the other Party (Indemnified Party) from and against any loss, cost,
claim, liability, damage, or expense (including reasonable attorneys fees) to
third parties for bodily injury, including death, and damage to property, to the
extent  arising out of negligence or wanton or willful misconduct by the
Indemnifying Party, its employees, agents or contractors in the performance of
this Agreement.  In addition, the Indemnifying Party shall, to the extent of its
negligence or wanton or willful misconduct, defend any action or suit brought by
a third party for bodily injury, including death, and damage or expense relating
to or arising out of negligence or wanton or willful misconduct by the
Indemnifying Party, its employees, agents, or contractors, in the performance of
this Agreement.  The Indemnified Party shall notify the Indemnifying Party
promptly, in writing, of any written claims, lawsuits, or demands by third
parties for which the Indemnified Party alleges that the Indemnifying Party is
responsible under this paragraph and tender the defense of such claim, lawsuit
or demand to the Indemnifying Party.  The Indemnified Party also shall cooperate
in every reasonable manner with the defense or settlement of such claim, demand
or lawsuit.  The Indemnifying Party shall not be liable under this subparagraph
for settlements by the Indemnified Party of any claim, demand, or lawsuit unless
the Indemnifying Party has approved the settlement in advance or unless the
defense of the claim, demand or lawsuit has been tendered to the Indemnifying
Party, in writing, and Indemnified Party has failed promptly to undertake the
defense.


17.0 Limitation of Liability

NEITHER PARTY SHALL BE LIABLE FOR ANY LOSS OF REVENUE OR PROFIT BY ANY THIRD
PARTY OR FOR ANY LOSS OR DAMAGE IN CONNECTION WITH OR ENSUING FROM THE
ACTIVITIES CONTEMPLATED BY THIS AGREEMENT, WHICH IS SUFFERED BY ANY SUCH THIRD
PARTY, WHETHER ARISING IN CONTRACT, TORT (INCLUDING WITHOUT LIMITATION
NEGLIGENCE OR STRICT LIABILITY), OR OTHERWISE AND WHETHER OR NOT INFORMED OF THE
POSSIBILITY OF SUCH DAMAGES IN ADVANCE.  WITH RESPECT TO CLAIMS ARISING OUT OF
THE PROVISION OF THE SERVICES UNDER THIS AGREEMENT, EITHER PARTY'S LIABILITY,
WHETHER IN CONTRACT, TORT, OR OTHERWISE, SHALL BE LIMITED TO DIRECT DAMAGES
WHICH SHALL NOT EXCEED THE TOTAL CHARGES FOR THE SERVICES PROVIDED.  UNDER NO
CIRCUMSTANCES SHALL EITHER PARTY BE RESPONSIBLE OR LIABLE FOR INDIRECT,
INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES, INCLUDING, BUT NOT LIMITED TO,
DAMAGES ARISING FROM THE USE OR PERFORMANCE OF THE SERVICES, DELAY, FAILURE TO
PROCESS CALENDAR-RELATED DATA CORRECTLY OR TO REPRESENT DATES
<PAGE>

WITHOUT AMBIGUITY TO CENTURY, ERROR OR LOSS OF DATA, PROFITS OR GOODWILL. IN
CONNECTION WITH THIS LIMITATION OF LIABILITY, THE PARTIES RECOGNIZE THAT GTE MAY
PROVIDE ADVICE, MAKE RECOMMENDATIONS, OR SUPPLY OTHER ANALYSES RELATED TO THE
PROVISION OF SERVICES DESCRIBED IN THIS AGREEMENT. GNI ACKNOWLEDGES AND AGREES
THAT THIS LIMITATION OF LIABILITY SHALL APPLY TO SUCH ADVICE, RECOMMENDATIONS,
AND ANALYSES. THE PARTIES EXPRESSLY AGREE THESE LIMITATIONS WILL APPLY
NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY LIMITED REMEDY.


18.0 Dispute Resolution

18.1 In the event either Party fails to perform any material provision of this
     Agreement, either Party may give notice to the other Party pursuant to the
     notification procedure set forth in Section 21, Notices/Performance
     Contact, of this Agreement.

18.2 If, after having provided such notice, the Parties fail to resolve any
     nonperformance issues set forth in such notice, the Parties may escalate
     their attempts at resolution by notifying the managerial contacts,
     identified below of the outstanding issues:

     GTE's Contact:                   GNI's Contact:

     GTE Network Services
     GNI -- Account Manager           Vendor Manager - GTENS
     600 Hidden Ridge
     Irving, Texas 75015

19.0 Default

If either Party fails to perform any material obligation under this Agreement or
violates any material term or condition of this Agreement, and such failure or
violation is not cured within thirty (30) calendar days following receipt of a
default notice from the other Party, then the other Party shall have the right
to terminate this Agreement upon written notice to the defaulting Party.


20.0 Force Majeure

Neither Party shall be held liable for any delay or failure in performance of
any part of this Agreement from any cause beyond its control and without its
fault or negligence, including, but, not limited to, acts of civil or military
authority, government relations, embargoes, epidemics, war, terrorist acts,
riots,
<PAGE>

insurrections, fires, explosions, nuclear accidents, strikes, extended power
blackouts, natural disasters such as earthquakes, floods, volcanic action,
unusually severe weather conditions or other major environmental disturbances,
inability to secure transportation or communications common carriers, or legal
and/or regulatory constraints affecting either of the Parties hereto in
performing their obligations hereunder. If such contingency occurs, the Party
delayed or unable to perform shall give reasonable notice to the other Party.

21.0 Notices/Performance Contact

21.1 All notices or other communications required or permitted to be made or
     given hereunder by one Party to the other Party shall be in writing and
     shall be deemed to have been given: (i) when hand delivered, or (ii) when
     sent by electronic facsimile (with confirmation of its receipt by the other
     Party) when sent during recipient's normal hours of business from Monday
     through Friday excluding holidays, otherwise on the next business say of
     receipt, (iii) on the third (3rd) business day after the day of deposit in
     the United States mail when sent by certified mail, postage prepaid and
     return receipt requested, or (iv) on the next business say excluding,
     excluding Saturdays, Sundays, and recipient's holidays, when sent by
     national overnight package delivery service for next day delivery with
     proof of delivery, and, in all cases, properly addressed to such other
     Party as set forth in the applicable Statement of Work or at such other
     address as may be specified by either Party by written notice sent or
     delivered in accordance with the terms hereof.

21.2 The day-to-day management of the relationship between the Parties in
     accordance with the terms and conditions of this Agreement shall be
     conducted by those designees set forth in the Statement of Work and who are
     not authorized to modify or amend this Agreement.

21.3 All invoices for Services under this Agreement shall be addressed to GNI as
     follows:

     GTE Global Networks Corporation
     Attn:  Vendor Cost management


22.0 Publicity

Unless otherwise agreed upon, neither Party shall publish or use the other
Party's name, pictures, symbols, or trade secrets from which the other Party's
name may be inferred or implied in any advertising, promotion, or any other
publicity matter relating directly or indirectly to this Agreement.  All
publicity regarding this Agreement is subject to the Parties' prior written
consent.
<PAGE>

23.0 Entire Agreement

23.1 This Agreement, including the Exhibits listed below, constitutes the entire
     agreement and understanding between the Parties with respect to the subject
     matter hereof and supersedes and replaces any prior or contemporaneous
     undertakings, commitments or agreements, oral or written, as to its subject
     matter:

               Exhibit A - Services Description
               Exhibit B - Statements of Work

23.2 This Agreement may be modified or amended only by written instrument,
     designated as an amendment or other words of like import, and signed by
     authorized representatives of the Parties on or after the date hereof.


24.0 Precedence of Documents

In case of conflict between provisions of this Agreement and provisions of any
invoice, order acknowledgement or other document submitted by GTE, the
provisions of this Agreement shall govern.  In case of conflict between the
provisions of this Agreement and the provisions of any of its Exhibits, the
provisions of the Agreement shall govern.


25.0 Applicable Law

This Agreement shall be governed by and construed in accordance with the laws of
the State of Texas and of the United States.


26.0 Regulatory Issues

This Agreement is subject at all times to any statute, order, rule, or
regulation, or any state of federal regulatory agency, having competent
jurisdiction over one or both of the Parties hereto, or the services provided
hereby as it pertains to affiliate relationships.  In addition, this Agreement
shall at all times be subject to changes, modifications, orders and rulings by
any state public utilities regulatory agency to the extent the affiliate
relationship created by Agreement is or becomes subject to jurisdiction of such
agency.  If the arrangement described in this Agreement is subject to advance
approval by the state public utilities regulatory agency, this Agreement shall
not become effective within that state until the business day after receipt by
GNI of written notice of such approval. GNI and GTENS agree to cooperate with
each other and with any applicable
<PAGE>

regulatory agency so that any and all necessary approvals may be obtained.
During the term of this Agreement, the Parties agree to continue to cooperate
with each other in any review of this Agreement by a regulatory agency so that
the benefits of this Agreement may be achieved. If such agency accepts this
Agreement in part and rejects it in part, or makes a material modification to
the Agreement as a condition of its approval, either Party may terminate the
Agreement as pertains to the affected state without penalty or liability.

27.0 Binding Effect

This Agreement is intended to benefit and shall be binding on the Parties hereto
and their respective legal representative, successors and permitted assigns.  It
is not intended to benefit or bind third parties and provides no remedy, claim,
liability, cause of action, or other right to any third party.


28.0 Separate Enforcement of Provisions

If, for any reason, any provision of this Agreement shall be finally determined
to be invalid, void, or unenforceable by a court of regulatory body of competent
jurisdiction, the remaining provisions of this Agreement shall remain in full
force and effect and shall in no way be affected, impaired or invalidated unless
removal of the provision in question results in frustration of the purpose of
this Agreement.  If a regulatory agency makes a modification to this Agreement,
this Agreement shall remain in effect as modified unless the modification
results in a material change to this Agreement.  In the event of a material
change, the Parties shall negotiate in good faith for lawful replacement
provisions.  If replacement provisions cannot be agreed upon within a reasonable
period, either Party may terminate this Agreement without penalty or liability
upon written notice to the other Party.


29.0 Headings

The headings in this Agreement are inserted for convenience and identification
only and are in no way intended to define or limit the scope, extent or intent
of this Agreement or any of the provisions hereof.


30.0 No Waiver

No failure or delay by either Party hereto in exercising any right, power or
privilege hereunder shall operate as a waiver thereof, nor shall any single or
partial exercise thereof preclude any other or future exercise of any right,
power, or privilege.
<PAGE>

31.0 Authority

Each individual executing this Agreement for and on behalf of a Party represents
that he or she is fully authorized and empowered to do so for and on behalf of
his or her principle.


32.0 Execution in Counterparts

This Agreement may be executed in any number of counterparts, each of which
shall be deemed an original, and all of which together shall constitute but one
and the same instrument.


IN WITNESS WHEREOF, the Parties have executed this Agreement on the date or
dates indicated below to be effective as of the Effective Date specified in the
initial paragraph of this Agreement.

GTE GLOBAL NETWORKS                GTE Network Services consisting
CORPORATION                        of the GTE Telephone
                                   Operating Companies listed on
                                   Attachment A

  By: /s/ T. George Hess               By: /s/ Larry J. Sparrow

Name: T. George Hess               Name:  Larry J. Sparrow

 Title:  Vice President             Title:  Vice President

 Date: Original signed 9/9/99       Date: Original signed 9/14/99

  By: /s/ Ondrea Hidley

  Name: Ondrea Hidley
  Title: Assistant Secretary

  Date: Original signed 9/10/99
<PAGE>

                                 ATTACHMENT A
                                 ------------

                       GTE Telephone Operating Companies

GTE Alaska Incorporated
GTE Arkansas Incorporated
GTE California Incorporated
GTE Florida Incorporated
GTE Hawaiian Telephone Company Incorporated
GTE Midwest Incorporated
GTE North Incorporated
GTE Northwest Incorporated,
GTE West Coast Incorporated
GTE South Incorporated
GTE Southwest Incorporated
Contel of Minnesota, Inc. d/b/a GTE Minnesota
Contel of the South, Inc. d/b/a GTE Systems of the South, d/b/a GTE Systems of
       Indiana, d/b/a/  GTE Systems of Michigan
<PAGE>

                                   EXHIBIT A
                                   ---------

The Scope of this Agreement as listed in Section reads as follows:

GTE will provide, through its Network Operations Center ("NOC"), network
monitoring of network enabling devices and processes twenty four (24) hours a
day, seven (7) days a week, three hundred sixty-five (365) days a year to
detect, escalate, restore, and follow-up on anomalies occurring in the network.
In addition, GTE will provide technical support to GNI for problems that cannot
be resolved on-site; these support services include network element event
problem resolution, network element reliability analysis and network traffic
management.

The following definitions are provided to further define the scope and explain
the intended meanings to be associated with terms used.

The network enabling devices to be monitored include the hardware and software
products that allow voice, data, or video access to the public communications
network and/or a private communications network and includes, but is not limited
to, the monitoring of switches, routers, fiber, video, lightwave multiplexing
equipment, digital cross connections, servers and hubs.

Detection is the identification, via informational indicators, of changing
conditions in the above mentioned devices.

Escalation is the referral of problems within a hierarchy to facilitate
resolution.

Restore is to eliminate conditions that are detrimental to normal operating
conditions.

Follow-up is verifying that steps were taken in the proper manner concerning a
detrimental condition and that such condition has not recurred.

An anomaly is an irregularity in the network.

Technical support is expertise that can be offered either on site or by
telephone to assist others in performing their duties.

Network element event problem resolution.  Once a problem is identified, it goes
through the necessary steps to be restored.

Network element reliability analysis.  Analysis of information data pertaining
to the operation or condition of a network element.

Network traffic management.  Management of the flow of traffic between network
elements or switches to prevent degradation of service.  In the event
<PAGE>

circumstances exist that may potentially cause a degradation of service, the NOC
will, at its sole discretion, reroute traffic in the network.
<PAGE>

                                   EXHIBIT B
                                   ---------


                              STATEMENTS OF WORK
                              ------------------


       THE FOLLOWING STATEMENTS OF WORK ARE ATTACHED TO THIS AGREEMENT:
       ----------------------------------------------------------------

Statement of Work 1      Technical Support for GTE Customer
                         Networks