<PAGE>

                                OPTION AGREEMENT

         THIS OPTION AGREEMENT ("Agreement") is made and entered into as of this
27th day of August, 2001 by and among Williams Communications, LLC, a Delaware
limited liability company ("Williams"), and Winstar Wireless, Inc. ("Winstar"),
a Delaware corporation.

         WHEREAS, Williams has constructed or will construct or obtain rights of
use in a fiber optic communication system; and

         WHEREAS, Williams and Winstar entered into a Wireless Fiber(SM) IRU
Agreement effective as of December 17, 1998 (the "Wireless IRU Agreement"); and

         WHEREAS, Winstar desires to acquire from Williams, and Williams desires
to provide to Winstar, an option to enter into the new IRU agreement attached
hereto as Exhibit 1 (the "New IRU Agreement"); and

         WHEREAS, Williams wishes to enter into an amendment to the Wireless IRU
Agreement in the form of Amendment Number One to Wireless Fiber(SM) IRU
Agreement and Winstar is willing to so amend;

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
contained herein, and for other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto, intending to be
legally bound, hereby agree as follows:

         1. Grant of Options. In consideration of Winstar's execution of
Amendment Number One to Wireless Fiber(SM) IRU Agreement and other good and
valuable consideration, the sufficiency of which is hereby acknowledged,
Williams grants to Winstar two options to enter into the New IRU Agreement
("Option 1" and "Option 2," respectively), which options are identical except
for the deadlines by which they may be exercised.

         2. Exercise of Option. In order to exercise either Option 1 or Option
2, Winstar shall deliver to Williams a notice of election (the "Notice of
Election") that specifies a date of commencement of the New IRU Agreement. The
New IRU Agreement shall become effective upon the date specified in the Notice
of Election as the date of commencement of the New IRU Agreement (the "New IRU
Commencement Date"), provided that Winstar has, on or before the New IRU
Commencement Date, executed and delivered to Williams a copy of the New IRU
Agreement, and provided, further, that, on or before the New IRU Commencement
Date, the Wireless IRU has been assumed pursuant to 11 U.S.C. Section 365 in a
confirmed plan of reorganization or has been assumed and assigned in connection
with an asset sale pursuant to 11 U.S.C. Section 363.

          3. Deadline for Exercise. The Notice of Election for Option 1 shall be
delivered, if at all, no later than December 31, 2001. The Notice of Election
for Option 2 shall be delivered, if at all, no sooner than January 1, 2002 and
no later than two (2) business days following the date on which an Order of the
United States Bankruptcy Court for the District of Delaware confirming a plan of
reorganization for Winstar (the "Plan") becomes a final order and the Plan has
become effective (the "Deadline for Exercise"). If neither Option I nor Option 2
is exercised




<PAGE>


by the Deadline for Exercise, or if Winstar's bankruptcy case is converted to a
Chapter 7 case, then both options shall expire, and Winstar shall immediately
return to Williams all original signature pages to the attached form of New IRU
Agreement executed by Williams. Williams agrees that it will not request,
directly or indirectly, that Winstar's bankruptcy case be converted to a Chapter
7 case.

         4. Assignment of Options. Winstar may assign this Agreement (and, in
the case of Section 4(e), below, pledge or grant a security interest in this
Agreement) without the prior written consent of Williams to:

                  (a) An entity that acquires all or substantially all of
         Winstar's assets,

                  (b) Any Affiliate of Winstar (as defined in the New IRU
         Agreement),

                  (c) A successor in a merger or acquisition of Winstar,

                  (d) An entity that acquires less than substantially all of
         Winstar's assets, provided that the entity has been determined to be
         financially solvent by mutual agreement or the assignment has been
         approved by the court; or

                  (e) In connection with any financing.

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

         6. Notice. Unless otherwise provided in this Agreement, all notices and
communications concerning this Agreement shall be in writing and addressed to
the other party as follows, or at such other address as may be designated in
writing to the other party:

<Table>
<S>                                                       <C>
         IF TO WINSTAR:                                   IF TO WILLIAMS:

            Winstar Wireless, Inc.                           Williams Communications, LLC
            685 THIRD AVENUE                                 ONE WILLIAMS CENTER, SUITE 26-5
            NEW YORK, NY 10017                               TULSA, OKLAHOMA 74172
            Attn: EVP, GENERAL COUNSEL                       Attn: CONTRACT ADMINISTRATION

         WITH A COPY TO:                                  WITH A COPY TO:

            Winstar Wireless, Inc.                           Williams Communications, LLC
            2545 HORSE PEN ROAD                              ONE WILLIAMS CENTER, SUITE 4100
            HERNDON, VIRGINIA 22171                          TULSA, OKLAHOMA 74172
            Attn: VP, COMMERCIAL AND LEGAL OPERATIONS        Attn: GENERAL COUNSEL
</Table>


Unless otherwise provided herein, notices shall be hand delivered, sent by
registered or certified U.S. Mail, postage prepaid, or by commercial overnight
delivery service, and shall be deemed served or delivered to the addressee or
its office when received at the address for notice specified above when hand
delivered, on the day after being sent when sent by overnight delivery service,
and three (3) days after deposit in the mail when sent by U.S. mail.



                                        2


<PAGE>









         7. Entire Agreement. This Agreement, together with its Exhibit,
constitutes the entire understanding and agreement between the parties hereto
concerning the subject matter hereof, superseding all prior oral or written
agreement or understandings. This Agreement may not be terminated, amended,
modified or changed except in writing signed by the parties hereto.

         8. Governing Law. The validity, construction and performance of this
Agreement shall be governed by the laws of the State of New York, without giving
effect to conflicts of law principles thereof.

         9. Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument. Such counterparts may be
exchanged by facsimile transmission (followed by delivery of the executed
original) and shall be deemed duly delivered upon acknowledgement of receipt
thereof by the recipient party.

         10. Interpretation. This Agreement is to be construed fairly and simply
and not strictly for or against either of the parties hereto. The Section
headings contained herein are for convenience of references only, are not part
of this Agreement, and shall not affect the meaning or interpretation of any
provision hereof.

          IN WITNESS WHEREOF and in confirmation of their consent to the terms
and conditions contained in this Agreement and intending to be legally bound
hereby, Williams and Winstar have executed and delivered this Agreement as of
the dates set forth below.






WINSTAR WIRELESS, INC.                    WILLIAMS COMMUNICATIONS, LLC



By:  /s/ C.Z. CZERNER                       By:  /s/ BRYAN J. DANCER
     -----------------------------              -------------------------------

Name:    C.Z. Czerner                       Name:      Bryan J. Dancer
     -----------------------------              -------------------------------

Title: Sr VP-Corporate Development        Title:  V.P. Business Development
      ----------------------------              -------------------------------

Date:  August 27, 2001                    Date:       8-27-01
     -----------------------------              -------------------------------



                                       3
<PAGE>
                                                                  EXECUTION COPY


                                  IRU AGREEMENT

                                     BETWEEN

                             WINSTAR WIRELESS, INC.

                                       AND

                         WILLIAMS COMMUNICATIONS, LLC


                              Dated
                                    -----------------


                                   (Long-Haul)


<PAGE>

                                  IRU AGREEMENT
                                   (Long-Haul)

         THIS IRU AGREEMENT (including the Exhibits and Schedules attached
hereto, this "Agreement") is made as of the New IRU Commencement Date
(hereafter defined) by and between WINSTAR WIRELESS, INC. ("Winstar"), a
Delaware corporation having its principal office at 685 Third Avenue, New York
City, New York 10017, and WILLIAMS COMMUNICATIONS, LLC ("Williams"), a Delaware
limited liability company, having its principal office at One Williams Center,
Tulsa, Oklahoma 74172.

                                   WITNESSETH:

         WHEREAS, Williams has constructed or will construct or obtain rights of
use in a fiber optic communication system (the "System") located along the
routes depicted in Exhibit A, Part I (the "Routes") and consisting of the System
Segments, as defined below; and

         WHEREAS, Winstar desires to acquire from Williams, and Williams desires
to provide to Winstar, the Network IRU as defined below upon the terms and
conditions set forth below;

         WHEREAS, Williams desires to sell and Winstar desires to buy certain
Services, as defined herein;

         NOW, THEREFORE, in consideration of the mutual promises set forth below
and other good and valuable consideration, the sufficiency of which is hereby
acknowledged, the parties hereby agree as follows:

1.       DEFINITIONS

         Capitalized terms and phrases used in this Agreement shall have the
following meanings:

                  (a)      "Acceptance" means the process of testing and
                           proofing the performance of the Winstar Fibers for
                           the purpose of delivery, set forth in Section 8 of
                           this Agreement, or the capacity or Service provided
                           under this Agreement as set forth in Section 5.2.
                           Winstar Fibers, capacity or Services which have been
                           accepted through the Acceptance process are
                           "Accepted."

                  (b)      "Acceptance Date" means the date on which the Winstar
                           Fibers are Accepted under Section 8.1 below.

                  (c)      "Acceptance Standards" means the standards set forth
                           in Exhibit D with respect to the testing of the
                           Winstar Fibers.

                  (d)      "Additional Services" means Telecommunications
                           Services in excess of the Capacity IRU, such excess
                           is not included in the Contract Price.


                                       1
<PAGE>

                  (e)      "Affiliate" means, with respect to any entity, any
                           other entity Controlling, Controlled by or under
                           common Control with such entity, whether directly or
                           indirectly through one or more intermediaries.

                  (f)      "Agreement" has the meaning set forth in the preamble
                           to this document.

                  (g)      "Ancillary Services" has the meaning set forth in
                           Section 6.4.

                  (h)      "Cable" means fiber optic cable installed pursuant to
                           this Agreement as part of the System (including any
                           replacement cable) and fibers contained therein,
                           including the Winstar Fibers, and associated splicing
                           connections, splice boxes and vaults, and conduit.

                  (i)      "Capacity" means the On-Net Telecommunications
                           Services set forth on Schedule B to this Agreement.

                  (j)      "Capacity IRU" has the meaning set forth in Section
                           2.1(b).

                  (k)      "Circuit" means a communications path with a
                           specified bandwidth.

                  (l)      "Claim" means any claim, action, dispute, or
                           proceeding of any kind between Winstar (or any of its
                           Affiliates, successors or assigns) and Williams (or
                           any of its Affiliates, successors or assigns) and any
                           other claim, transaction, occurrence, loss,
                           liability, expense or other matter arising out of, in
                           connection with, or in any way related to, the
                           Network IRU, the System, this Agreement or any other
                           instrument, arrangement or understanding related to
                           the Network IRU.

                  (m)      "Claimant" has the meaning set forth in Section 15.1.

                  (n)      "Collateral" has the meaning set forth in Exhibit K.

                  (o)      "Collocation Service" has the meaning set forth in
                           Exhibit C.

                  (p)      "Connecting Point" means a point where the network or
                           facilities of Winstar will connect to the System.

                  (q)      "Contract Price" means the purchase price for the
                           Network IRU in the gross amount of two hundred
                           forty-five million five hundred twenty seven thousand
                           two hundred dollars ($245,527,200.00), comprised of
                           one hundred two million three hundred ninety-seven
                           thousand six hundred eighty dollars ($102,397,630.00)
                           for the Winstar IRU and one hundred forty-three
                           million one hundred twenty-nine thousand five hundred
                           twenty dollars ($143,129,520.00) for the Capacity IRU
                           payable together in Monthly Payments, and is subject
                           to reduction by Section 8.4 and 13.1(b). or other
                           reductions allowed under this Agreement or as agreed
                           by the Parties.


                                      2
<PAGE>

                  (r)      "Control" and its derivatives mean legal, beneficial
                           or equitable ownership, directly or indirectly, of
                           more than fifty percent (50%) of the outstanding
                           voting capital stock (or other ownership interest, if
                           not a corporation) of an entity or management or
                           operational control over such entity.

                  (s)      "Costs" means actual, direct costs incurred and
                           computed in accordance with the established
                           accounting procedures used by Williams to bill third
                           parties for reimbursable projects. All Costs shall be
                           computed in accordance with generally accepted
                           accounting principles. Such actual, direct costs
                           include the following:

                           (i)      Labor costs, including wages and salaries,
                                    and benefits, plus the overhead allocable to
                                    such labor costs (overhead allocation
                                    percentage shall not exceed the lesser of:
                                    (i) the percentage Williams allocates to its
                                    internal projects; or (ii) thirty percent
                                    (30%)); and

                           (ii)     Other direct costs and out-of-pocket
                                    expenses on a pass-through basis (such as
                                    equipment, materials, supplies, contract
                                    services, costs of capital, Required Rights,
                                    sales, use or similar taxes, etc.) plus ten
                                    percent (10%) of such expenses; but,

                           (iii)    Less any cost or expense reimbursed by a
                                    third party.

                  (t)      "Cover" means the remedy for late delivery of the
                           Winstar Fibers provided in Section 8.3 of this
                           Agreement.

                  (u)      "Deduction Section" has the meaning set forth in
                           Section 25.1(l).

                  (v)      "Due Date" has the meaning set forth in Section 13.1.

                  (w)      "Facility Owners/Lenders" means any entity (other
                           than Williams) that: (a) owns any portion of the
                           System or any property or security interest therein,
                           (b) leases to Williams, or provides an IRU to
                           Williams in, any portion of the System, or (c) is a
                           Lender with respect to Williams or any Affiliates of
                           Williams.

                  (x)      "FCC" means the Federal Communications Commission.

                  (y)      "Fiber Acceptance Testing" means the fiber acceptance
                           testing described in Exhibit D.

                  (z)      "Fibers" means any optical fibers contained in the
                           System including the Winstar Fibers, the fibers of
                           Williams and the fibers of any third party in the
                           System excluding, however, any fibers granted
                           (whether through ownership, IRU, lease, or otherwise)
                           to governmental entities in exchange


                                      3
<PAGE>


                           for the use of streets, rights of way, or other
                           property under the jurisdiction of such entity.

                  (aa)     "Force Majeure Events" has the meaning set forth in
                           Article 23.1.

                  (bb)     "Indefeasible Right of Use" or "IRU" means an
                           exclusive, indefeasible right to use the specified
                           property or capacity in the manner contemplated by
                           this Agreement; provided, however, that the grant of
                           an IRU shall not convey title, ownership, or rights
                           of possession in the System, the Winstar Fibers, the
                           Cable, the Right-of-Way Agreements, or any other real
                           or personal property.

                  (cc)     "Indemnitor" has the meaning set forth in Section
                           15.1.

                  (dd)     "Intellectual Property Rights" means patent,
                           copyright, trademark, trade secret or other
                           proprietary rights with respect to any work product
                           in which such rights could inure.

                  (ee)     "Interconnection" means the connections of the
                           Winstar equipment with the Williams Network or
                           third-party networks.

                  (ff)     "Interim Agreement" means the Interim Agreement by
                           and between the Parties executed on August 15, 2001.

                  (gg)     "Interim Services" means the Services provided to
                           Winstar pursuant to the Interim Agreement.

                  (hh)     "IRU Term" has the meaning set forth in Section 10.1.

                  (ii)     "LEC" means a local exchange carrier.

                  (jj)     "Lender" has the meaning set forth in Section 2.2.

                  (kk)     "Losses" means all liabilities, damages and related
                           costs and expenses (including fines, levies,
                           assessments, reasonable legal fees and disbursements
                           and costs of investigation, litigation, settlement,
                           judgment, interest and penalties) directly incurred
                           by a party.

                  (ll)     "Material Improvements" has the meaning set forth in
                           Exhibit C-1.

                  (mm)     "Mean Time to Restore" has the meaning set forth in
                           the applicable schedules of Exhibit B.

                  (nn)     "Minimum Term Liability" has the meaning set forth in
                           Section 5.3(b).

                  (oo)     "Monthly Payments" means the monthly amounts payable
                           to Williams for the Winstar IRU and the Capacity IRU
                           combined together granted under this Agreement as set
                           forth in Sections 3.1.


                                       4
<PAGE>

                  (pp)     "NCC" means Network Control Center, as set forth in
                           Exhibit I, Section 1(A).

                  (qq)     "Network IRU" has the meaning set forth in Section
                           2.1.

                  (rr)     "New IRU Commencement Date" means the date upon which
                           the Network IRU is made effective pursuant to the
                           terms of the Option Agreement, which shall be no
                           earlier than the day after day on which the first
                           monthly installment of the Monthly Payment is paid to
                           Williams, and shall be the date on which this
                           Agreement becomes effective.

                  (ss)     "Notice of Election" has the meaning set forth in
                           Section 15.2(a).

                  (tt)     "OOS" means Out-of-Spec, as set forth in Exhibit D,
                           Section 1(B).

                  (uu)     "Off Net" means a Circuit that is not On Net.

                  (vv)     "On Net" means a Circuit traversing the Williams
                           Network between two Williams points of presence.

                  (ww)     "OTDR" means optical time domain reflectometer, as
                           set forth in Exhibit D, Section 1(A).

                  (xx)     "Other Services" means local access, Interconnection,
                           Ancillary Services and Collocation Services.

                  (yy)     "Payment Deductions" has the meaning set forth in
                           Section 25.1(e).

                  (zz)     "Payment Terms" has the meaning set forth in Section
                           3.1.

                  (aaa)    "Point of Presence" or "POP" means a specified
                           location at which Williams originates or terminates
                           services.

                  (bbb)    "Premises" has the meaning set forth in Exhibit C.

                  (ccc)    "Prime Rate" means, with respect of any period, the
                           rate published as Chase Manhattan's prime rate in the
                           Wall Street Journal, or any successor publication
                           thereto, from time to time during such period. (mmm)
                           "Pro Rata Share" means a proportion equal to a
                           fraction, the numerator of which is the number of
                           Winstar Fibers and the denominator of which is all
                           Fibers in the relevant System Segment Portion(s). If
                           this fraction varies over different System Segment
                           Portions, then the Pro Rata Share shall be equal to
                           the weighted average (weighted by length as set forth
                           in Williams' as-built drawings) of the relevant
                           System Segment Portions. For example, if the fraction
                           for 100 feet of the relevant System Segment Portion
                           is 0.1 and the fraction for the remaining 50 feet of
                           the relevant System Segment


                                      5
<PAGE>


                           Portion is 0.07, the weighted average for the entire
                           System Segment Portion would be 0.09.

                  (ddd)    "Released Party" means each of the following (but
                           excludes Williams and Winstar):

                           (i)      Any Affiliates or Lenders of the other party
                                    and any Facility Owners/Lenders;

                           (ii)     Any employee, officer, director,
                                    stockholder, partner, member, or trustee of
                                    the other party or of its Affiliates,
                                    Lenders, or Facility Owners/Lenders; or

                           (iii)    Assignees of the entities included in the
                                    above subparagraphs (a) or (b) and any
                                    employee, officer, director, stockholder,
                                    partner, member, or trustee of such
                                    assignees.

                  (eee)    "Representatives" has the meaning set forth in
                           Section 20.2(a).

                  (fff)    "Requested Start Date" means the date specified as
                           delivery date in a Service Order.

                  (ggg)    "Required Rights" has the meaning set forth in
                           Section 4.1.

                  (hhh)    "Right-of-Way Agreements means rights, licenses,
                           authorizations, easements, leases, fee interests, or
                           agreements that provide for the occupancy by the
                           System of real property or fixtures (such as conduit,
                           bridges, river crossings, or transmission towers).

                  (iii)    "Route" has the meaning set forth in the Recitals
                           above.

                  (jjj)    "Routine Maintenance" has the meaning set forth in
                           Section 11.1.

                  (kkk)    "Security Interest" has the meaning set forth in
                           Exhibit K.

                  (lll)    "Service Orders" has the meaning set forth in
                           Section 5.2(a).

                  (mmm)    "Service Term" means with respect to the provision of
                           Telecommunications Services, Additional Services or
                           Other Services, the length of time specified in the
                           applicable Service Order during which Williams will
                           provide such Telecommunications Services, Additional
                           Services or Other Services

                  (nnn)    "Space" has the meaning set forth in Section 1.1 of
                           Schedule C.


                                      6
<PAGE>

                  (ooo)    "Start Date" means, with respect to any
                           Telecommunications Services or Other Services Winstar
                           requests Williams to provide hereunder, the first day
                           on which such services are provided.

                  (ppp)    "System" shall have the meaning set forth in the
                           Recitals above.

                  (qqq)    "System Segment" means one of the System Segment
                           Portions identified as a System Segment in Exhibit A,
                           Part 2.

                  (rrr)    "System Segment Portion" means a discrete portion of
                           the System and may refer to a span (a portion of the
                           System between two Transmission Sites or between a
                           Transmission Site and a Point of Presence or System
                           end point), a portion between two Points of Presence
                           or a Point of Presence and a System end point, or a
                           portion of the System affected by a relocation or
                           other circumstance.

                  (sss)    "Telecommunications Services" means interexchange
                           telecommunications capacity on Williams' Network (or
                           third parties' telecommunications facilities) at the
                           DS-3, OC-3, OC-12 and OC-48 levels but excluding
                           Other Service.

                  (ttt)    "Term" has the meaning set forth in Section 10.1.

                  (uuu)    "Third Party Service Provider" means any third party
                           provider, operator or maintenance repair contractor
                           of facilities employed by Williams in connection with
                           the provision of the Network IRU, Telecommunications
                           Services or Other Services.

                  (vvv)    "Transmission Sites" means the optical amplifier,
                           regenerator, and junction sites along each System
                           Segment.

                  (www)    "UCC" shall mean the Uniform Commercial Code as in
                           effect in the State of New York, as it may be amended
                           from time to time.

                  (xxx)    "Williams" means Williams Communications, LLC, a
                           Delaware limited liability company, formerly known as
                           Williams Communications, Inc.

                  (yyy)    "Williams Network" means the telecommunications
                           facilities owned or operated by Williams and used to
                           provide services between the cities listed on
                           Williams published POP list, as such may be added to
                           as Williams grows its network during the Term.

                  (zzz)    "Winstar" has the meaning set forth in the first
                           paragraph of this document.


                                        7
<PAGE>

                  (aaaa)   "Winstar Equipment" means optronic (opto-electrical),
                           electronic, or optical equipment, or materials,
                           facilities, or other equipment (other than the
                           System) owned, possessed, or utilized by Winstar

                  (bbbb)   "Winstar Facilities" has the meaning set forth in
                           Section 27.3.

                  (cccc)   "Winstar Fibers" has the meaning set forth in Section
                           2.1.

                  (dddd)   "Winstar IRU" has the meaning set forth in Section
                           2.1.

                  (eeee)   "Wireless IRU" shall mean that certain contract
                           entitled "Wireless Fiber IRU Agreement by and
                           between Winstar Wireless, Inc. and Williams
                           Communications, Inc.," effective as of December 17,
                           1998.

2.       CONVEYANCE OF DARK FIBER IRUS AND GRANT OF OPTION

         2.1.     GRANT OF NETWORK IRU.

                  In consideration of the payment of the Contract Price to
                  Williams as set forth herein and upon the New IRU Commencement
                  Date, Williams hereby grants the "Network IRU" to Winstar for
                  the purposes described herein and on the terms and subject to
                  the conditions set forth herein. The Network IRU comprises:

                  (a)      An exclusive Indefeasible Right of Use (the "Winstar
                           IRU"), effective as of the Acceptance Date for each
                           System Segment effective on the New IRU Commencement
                           Date, in:

                  Two (2)  strands of optical fiber, in each System Segment,
                           throughout the length of the Route as specified in
                           Exhibit A-2 and four (4) strands of optical fiber on
                           the Houston to Atlanta System Segment, as specified
                           in Exhibit A-2 (the "Winstar Fibers"); and

                  (b)      An exclusive Indefeasible Right of Use in On-Net
                           Telecommunications Services (the "Capacity IRU"),
                           effective as of the IRU Commencement Date, for the
                           circuits identified in Exhibit H to the Interim
                           Agreement.

         2.2.     FINANCING ARRANGEMENTS.

                  Each party may, directly or through an Affiliate, enter into
                  financing arrangements (including secured loans, leases, sales
                  with lease-back, leases with lease-back arrangements,
                  purchase-money or vendor financing, conditional sales
                  transactions or other arrangements) with one or more financial
                  institutions, vendors, suppliers or other financing sources
                  (each a "Lender"), that, with respect to Williams, relate to
                  the System and, with respect to Winstar, relate to the Network
                  IRU (and not to


                                       8
<PAGE>

                  any physical property right in the System), subject to
                  Williams' rights pursuant to the Payment Terms.

         2.3.     INCLUSION IN WINSTAR'S BID PROCESS.

                  During the Term, anytime Winstar seeks to obtain domestic
                  interexchange telecommunications services to fulfill its
                  business requirements (including dark fiber, data, voice and
                  video circuits) it shall always include Williams in such
                  consideration if Williams is responsive to Winstar's requests
                  and Williams' products, when compared to similar offerings in
                  the marketplace, are of equivalent or better quality,
                  availability and price.

         2.4.     NO TITLE TO REALTY OR PERSONALTY.

                  Neither this Agreement nor the grant of the Network IRU
                  effected hereby conveys any form or type of title in any real
                  or personal property, including the System or any portion
                  thereof or in any transmission or other facilities or
                  equipment whether or not related to the provision of
                  Telecommunications Services, Other Services, or Additional
                  Services. Williams and Winstar intend that this Agreement
                  constitutes a contractual right of use and not a sale or lease
                  of the Winstar Fibers.

         2.5.     WILLIAMS SECURITY INTEREST.

                  (a)      Effect and Intention of this Section. Nothing in this
                           Section 2.5 shall vary, alter or modify the
                           provisions of Section 2.4 of this Agreement. The
                           grant of the Security Interest to Williams as set
                           forth in Exhibit K is not intended to and shall not
                           be construed to create any rights in any of the
                           Collateral in favor of Winstar which are not granted
                           by other provisions of this Agreement; provided,
                           however, that the provisions of this Section 2.5
                           shall be effective regardless of whether this
                           Agreement creates an IRU or some other interest in
                           the Winstar Fibers.

                  (b)      Security Interest. As security for the payment or
                           performance under this Agreement, as the case may be,
                           Winstar grants Williams the Security Interest set
                           forth in Exhibit K.

3.       CONSIDERATION FOR IRU

         3.1.     CONTRACT PRICE.

                  As consideration for the Network IRU, Winstar shall pay the
                  Contract Price in combined Monthly Payments, in the amount of
                  four hundred twenty six thousand six hundred fifty eight
                  dollars ($426,65S.00) for the Winstar IRU and five hundred
                  ninety six thousand three hundred seventy-three dollars
                  ($596,373.00) for the Capacity IRU, together for a Monthly
                  Payment of one million twenty-three thousand thirty-one
                  dollars ($1,023,031.00), subject to reduction by Section 8.4,
                  and 13.1(b) or other reductions allowed under this Agreement
                  or as agreed by the


                                        9
<PAGE>

                  Parties. The Monthly Payments shall be made in accordance with
                  the payment and other terms set forth in Section 13, Invoicing
                  and Payment and subject to the terms set forth in Exhibit K
                  (the "Payment Terms").

4.       CONSTRUCTION

         4.1.     CONSTRUCTION REPRESENTATIONS, WARRANTIES AND COVENANTS.

                  (a)      Williams represents, warrants and covenants that, as
                           of the Acceptance Date for each System Segment, it
                           (or the underlying facility owner on Williams'
                           behalf) shall have obtained the following rights
                           (collectively, the "Required Rights"):

                           (i)      all Right-of-Way Agreements necessary for
                                    the installation and use of that System
                                    Segment or Circuit, as the case may be;

                           (ii)     the rights to use those System Segment
                                    Portions it does not own and the right to
                                    grant the Network IRU with respect to such
                                    System Segment Portions or Circuits, as the
                                    case may be;

                  (b)      Williams represents, warrants and covenants that, for
                           each System Segment,

                           (i)      that System Segment has been designed,
                                    engineered, installed, and constructed in
                                    accordance with the specifications set
                                    forth in Exhibits D, E, and F; and

                           (ii)     throughout the Term, the exercise of rights
                                    by or on behalf of Williams' Facilities
                                    Owners/Lenders shall not deprive Winstar of
                                    the peaceful and quiet enjoyment of the
                                    Winstar IRU in that System Segment, or of
                                    the use of the Capacity IRU as specified in
                                    this Agreement.

         4.2.     RENEWAL OF REQUIRED RIGHTS.

                  Williams shall renew or replace, as necessary to the provision
                  of the Network IRU from time to time, the existing Required
                  Rights for each System Segment Term.

         4.3.     AS-BUILT DRAWINGS.

                  Within six (6) months after the Acceptance Date for any System
                  Segment, Williams shall provide Winstar with as-built drawings
                  for that System Segment which have not yet been provided, in
                  compliance with the specifications for as-built drawings set
                  forth in Exhibit H. Williams will provide all completed
                  as-built drawings within 30 days.


                                       10
<PAGE>

5.       ORDERING AND PROVISIONING

         5.1.     PROVISION OF CAPACITY SERVICE.

                  (a)      Inasmuch as the deployment of the System does not
                           currently reach all locations set forth in Part 1 of
                           Exhibit A, Williams shall provide, subject to
                           availability and on a non-discriminatory basis,
                           Telecommunications Services on the Williams Network
                           in accordance with the terms of this Agreement and
                           the terms located in Exhibit B. The
                           Telecommunications Services comprising the Capacity
                           IRU are fixed as of the date of execution of the
                           Interim Agreement and are specified in Attachment 1
                           to the Interim Agreement. All such Telecommunications
                           Services are deemed Accepted.

                  (b)      At the request of Williams, Winstar shall pay for
                           Other Services or Additional Services requested by
                           Winstar in writing in accordance with the terms of
                           this Agreement.

                  (c)      Winstar shall request Other Services and Additional
                           Services in writing through its authorized
                           representatives designated by Winstar in writing.
                           Winstar shall have no liability for and Williams
                           shall have no obligation to provide any Additional
                           Services or Other Services not placed by Winstar's
                           authorized representative.

         5.2.     SERVICE ORDERS FOR OTHER SERVICES AND ADDITIONAL SERVICES.

                  (a)      Additional Services, and Other Services requested by
                           Winstar hereunder shall be requested on Williams
                           Service Order forms in effect from time to time
                           ("Service Orders"). Each Service Order shall
                           reference this Agreement. In addition to issuing a
                           Service Order for such Service, Customer may order
                           certain Switched Voice Services in an electronic
                           batch format approved by Williams ("Batch Order").
                           Williams shall accept any Service Order under this
                           Agreement that complies with the terms and conditions
                           set forth herein, subject to availability and credit
                           approval at the time Winstar places such Service
                           Order. Williams reserves the right to reject a
                           Service Order that does not conform with the terms
                           and conditions of this Agreement and such
                           non-conforming Service Order shall have no force or
                           effect hereunder.

                  (b)      A Service Order is deemed accepted (subject to
                           availability) by Williams when Williams' Service
                           Delivery department transmits, within 3 business days
                           after receiving Winstar's Service Order, an
                           electronic Order Confirmation Document ("OCD") to
                           Winstar indicating that Winstar's order is being
                           processed by Williams; provided however, Williams
                           will not issue an OCD for Switched Voice Services.


                                       11
<PAGE>
                  (c)      Each Service Order will indicate a Requested Start
                           Date for the Circuit, the desired term of the
                           Circuit, specific city pairs, applicable bandwidth,
                           whether the Circuit(s) are to be expedited or
                           provided in normal intervals and any other parameters
                           required or information necessary to enable Williams
                           to provide the Service. In the event that Williams is
                           unable to meet Winstar's Requested Start Date,
                           Williams will notify Winstar of the date when
                           Williams believes the Service will be available and
                           Winstar's Requested Start Date will be changed to
                           reflect the number of days of delay or advance, as
                           appropriate. Failure of Williams to deliver by
                           Winstar's Requested Start Date shall not constitute a
                           default under this Agreement and Williams shall not
                           be liable to pay to Winstar any penalties or damages
                           for Williams' failure to meet Winstar's Requested
                           Start Date.

                  (d)      Any conflicting, different or additional terms and
                           conditions contained in Winstar's acknowledgment or
                           Service Order or elsewhere are deemed objected to by
                           Williams and shall not constitute part of this
                           Agreement. No action by Williams (including
                           fulfillment of such Service Order) shall be construed
                           as binding or estopping Williams with respect to such
                           conflicting, different or additional term or
                           condition, unless the Service Order containing said
                           term or condition has been signed by an authorized
                           representative of Williams.

                  (e)      Williams will issue to Winstar an electronic notice
                           that Service is available ("Turn Up Acknowledgement"
                           or "TUA"). The TUA will indicate that all the
                           relevant Service ordered through Williams has been
                           tested by Williams and that the Williams' Service
                           meets or exceeds the Technical Specifications set
                           forth in the relevant Service Schedule. The TUA will
                           also set forth the date Winstar's Service is
                           available for use by Winstar and upon which Williams
                           shall commence charging for the Service ("Circuit
                           Effective Billing Date").

                           Winstar shall be deemed to have accepted Service and
                           Williams shall begin billing for the Service as of
                           the Circuit Effective Billing Date, provided that, if
                           Winstar notifies Williams' Service Delivery
                           Department in writing within four (4) business days
                           of the Circuit Effective Billing Date that Williams'
                           Service is in material non-compliance with the
                           applicable Technical Specifications and if, upon
                           investigation, such material non-compliance is due
                           solely to Williams fault, then Williams shall correct
                           the non-compliance and make the appropriate
                           adjustment to Winstar's billings under this
                           Agreement. The occurrence of any such non-compliance
                           shall not constitute a default under this Agreement
                           and Williams shall not be liable to pay to Winstar
                           any penalties or damages resulting from any such
                           non-compliance, except for the Outage Credits
                           respecting On-Net Telecommunications Services
                           provided pursuant to Exhibit B. Charges for Service
                           begin accruing upon Circuit Effective


                                       12
<PAGE>
                           Billing Date, regardless of whether Winstar is
                           actually using the Services, or is ready to test and
                           accept the Services.

                  (f)      If Acceptance for any Circuit does not occur sixty
                           (60) days of the Deadline Date, Winstar may terminate
                           this Agreement with respect to the delayed Circuit by
                           notice to Williams.

         5.3.     CHANGES IN SERVICE PARAMETERS.

                  (a)      Winstar may disconnect Off-Net Telecommunications
                           Service, Other Services, or Additional Services
                           provided by a Third-Party Service Provider pursuant
                           to a Service Order by providing sixty (60) days'
                           prior written notice and paying any and all amounts
                           properly due that Provider for the affected Service
                           Order.

                  (b)      Following the relevant Start Date for any On-Net
                           service, including the Capacity IRU, Winstar may
                           disconnect or reconfigure that service upon sixty
                           (60) days' prior-written notice. If that action
                           relates to a Circuit that has not been in place for
                           at least one (1) year from its Start Date, Winstar
                           shall pay Williams an amount equal to the total of
                           the monthly charges for one year of service of such
                           Circuit, less the amount of monthly charges actually
                           paid at the time of service disconnection (the
                           "Minimum Term Liability").

6.       LOCAL ACCESS SERVICES

         6.1.     LOCAL ACCESS SERVICES.

                  Williams may obtain "Local Access Service" for Winstar, which
                  is defined as the telecommunications facilities or services
                  connecting a Winstar-designated termination point to a point
                  of presence ("POP") designated by Williams. The term Local
                  Access Service, as used throughout this Agreement, may include
                  both domestic U.S. and foreign Local Access Service. Winstar
                  shall execute a Letter of Agency, in a form provided by
                  Williams, authorizing Williams to interact directly with the
                  Local Access Service provider(s) to obtain the Local Access
                  Service. Winstar shall pay all charges including, without
                  limitation, monthly charges, usage charges, installation
                  charges, non-recurring charges, or applicable
                  termination/cancellation charges, of the Local Access Service
                  provider(s).

         6.2.     WILLIAMS' PROVISIONING, TESTING, AND CHARGING FOR LOCAL ACCESS
                  SERVICES.

                  For Local Access Services ordered by Williams, Williams shall
                  provision and conduct the initial testing of an
                  interconnection between the Williams' Service set forth in the
                  Service Order and the Local Access Service. Williams shall
                  coordinate the installation of the Local Access Service with
                  the Williams' Service.


                                       13
<PAGE>

                  Local Access Service charges shall accrue at the then-current
                  tariff rate (or the standard published rate, if there is no
                  tariff rate) of the Local Access Service provider. If the
                  applicable rate for Local Access Service is changed by the
                  Local Access Service provider, such changes will be passed
                  through to, and be borne by, Winstar. In the event Williams'
                  Services are not ready at the same time as the Williams'
                  ordered Local Access Service, Williams will not begin billing
                  Winstar for such Local Access Services until the related
                  Williams' Services are turned up.

         6.3.     WINSTAR ORDERED LOCAL ACCESS.

                  Winstar may, in conformance with Williams' policies on third
                  parties providing connectivity into a Williams' POP, order its
                  own Local Access Services from a vendor who has established
                  entrance facilities in Williams' POP ("Approved Vendor"). In
                  the event Winstar desires to order Local Access Services from
                  someone other than an Approved Vendor, Winstar must get
                  Williams' prior written permission, which shall not be
                  unreasonably withheld. In such event, the Local Access Service
                  provider shall directly bill Winstar for such Services.
                  Williams may charge Winstar for any associated entrance
                  facility or mileage charges if it provides Carrier Facility
                  Assignment ("CFA") to Winstar. Winstar shall ensure that the
                  Winstar-ordered Local Access Services are turned up at the
                  same time as the Williams' Services. If the Winstar-ordered
                  Local Access Services are not ready as of the Circuit
                  Effective Billing Date, Winstar shall nonetheless be obligated
                  to pay for Williams' Services as of the Circuit Effective
                  Billing Date, so long as the delay in the provision of the
                  Local Access Services is not attributable to Williams.

         6.4.     ANCILLARY SERVICES.

                  Williams may also provide other services to Winstar for
                  reasons including, but not limited to: (a) Winstar's request
                  to expedite Telecommunications Services availability to a date
                  earlier than Williams' published installation interval or a
                  previously accepted Start Date; (b) Telecommunications
                  Services redesign or other activity occasioned by receipt of
                  inaccurate information from Winstar; (c) Winstar's request for
                  use of routes or facilities other than those selected by
                  Williams for provision of the Telecommunications Services; and
                  (d) other circumstances in which extraordinary costs and
                  expenses are generated at the written request of Winstar and
                  incurred by Williams (collectively, "Ancillary Services").

7.       CONNECTION TO THE SYSTEM AND COLLOCATION

         7.1.     COLLOCATION.

                  Winstar shall have the right to use Transmission Sites along
                  the Route and to collocate equipment in Williams' points of
                  presence pursuant Exhibit C. Williams will provide the
                  collocation space requested in Exhibit A-3


                                       14
<PAGE>

                  pursuant to Exhibit C. Such Transmission Sites shall meet or
                  exceed the power and building requirements specified in
                  Exhibit C. Winstar shall provide, maintain, and for all
                  purposes be solely responsible for all Winstar Equipment at
                  Transmission Sites or other locations.

         7.2.     INTERCONNECTION.

                  Subject to the provisions herein, Winstar shall pay for and
                  arrange all connections of its facilities with the Winstar
                  Fibers. Winstar shall pay Williams for any Costs incurred as a
                  result of making such connections and shall at its own cost
                  obtain all rights from third parties required to make such
                  connections. Williams' Costs for any requested connection
                  shall be estimated and Winstar shall pay Williams eighty
                  percent (80%) of such estimate prior to the work being
                  performed by Williams. Winstar shall pay the balance of the
                  actual Costs incurred by Williams in making the connection
                  within thirty (30) days of receipt of an invoice therefor. In
                  the event the estimated Costs exceed the actual Costs,
                  Williams shall refund Winstar the difference. Such connections
                  shall be made only as set forth in Exhibit B.

8.       ACCEPTANCE AND TESTING OF FIBERS

         8.1      FIBER ACCEPTANCE TESTING.

                  Exhibit D sets forth Fiber Acceptance Testing procedures,
                  tests deliverables that Williams shall provide to Winstar, and
                  procedures for determining the Acceptance Date of a System
                  Segment.

         8.2      ACCEPTANCE DATE OBLIGATIONS.

                  As of the Acceptance Date of Winstar Fibers in any System
                  Segment:

                  (a)      Williams or the underlying facility owner shall have
                           obtained all rights, licenses, authorizations,
                           easements, leases, fee interests, or agreements that
                           provide for the occupancy by such System Segment of
                           real property or fixtures (such as conduit, bridges,
                           river crossings, or transmissions towers);

                  (b)      Williams shall have obtained by IRU agreement, lease
                           or otherwise the right to use any portion of the
                           System along the System Segment it does not own; and

                  (c)      such System Segment shall be designed, engineered,
                           installed, and constructed in accordance with the
                           specifications set forth in Exhibits D, E, and F.


                                       15
<PAGE>


                  The rights Williams is required to obtain pursuant to
                  Subsections (a) and (b) above are referred to as "Required
                  Rights." Consistent with the terms of this Section 8.2,
                  Williams shall renew or replace existing Required Rights
                  through the Term.

                  The System Segments previously Accepted by Winstar, including
                  those listed on Exhibit A-2, and identified as Accepted, are
                  deemed Accepted.

         8.3      TIMELY COMPLETION

                  The estimated completion dates for completion of construction,
                  installation, William' Fiber Acceptance Testing, and hand-over
                  of Williams' test results for each System Segment which has
                  not already been Accepted are set forth in Exhibit A-2
                  ("Estimated Completion Date"). The deadline date for actual
                  completion and testing of each System Segment which has not
                  already been Accepted shall be the later of one hundred and
                  twenty (120) calendar days after (a) the applicable Estimated
                  Completion Date for such System Segment, or (b) the Estimated
                  Completion Date for such System Segment (as extended due to
                  Force Majeure Events) or as expressly permitted by this
                  Agreement (the "Deadline Date"). If Williams does not meet the
                  Deadline Date for any System Segment, and the parties are
                  unable, in good faith, to agree to an alternative Deadline
                  Date, Winstar's sole and exclusive remedy for such failure
                  shall be to obtain Cover (as hereinafter defined) beginning on
                  the Deadline Date for the System Segments not made available
                  and ending on the date such System Segments are Accepted. The
                  term "Cover" shall mean, and shall be satisfied by Williams'
                  providing, at Williams' expense: (a) such capacity as is
                  required for Winstar to carry those Circuits it would have
                  migrated to the Winstar Fibers, and (b) such other capacity as
                  is needed to fulfill Winstar's increase in usage (based on
                  actual orders of its customers), until the Winstar Fibers are
                  Accepted. In any event, Williams will provide such Cover
                  capacity in ATM, private line, or frame relay formats, at
                  Winstar's option.

         8.4      TERMINATION RIGHT.

                  If the Acceptance Date does not occur within one hundred
                  eighty (180) days of the Deadline Date, Winstar may terminate
                  this Agreement with respect to the relevant System Segment by
                  written notice to Williams. Within thirty (30) calendar days
                  after receipt of such notice, Williams shall, as Winstar's
                  exclusive remedy for such non-occurrence, reduce the Monthly
                  Payment by the Pro Rata Share of the Monthly Payment relating
                  to the terminated System Segment and the parties shall have no
                  further obligations with respect to such System Segment. If
                  Winstar exercises its right to terminate the Agreement with
                  respect to the relevant System Segment, such termination shall
                  be Winstar's exclusive remedy for the delay or failure of
                  delivery.


                                       16
<PAGE>

9.       USE OF THE SYSTEM

         9.1.     USE OF WINSTAR FIBERS.

                  Winstar may use the Winstar Fibers for any lawful purpose in
                  accordance with the terms and conditions set forth in this
                  Agreement.

         9.2.    NOTICE OF DAMAGE.

                  Winstar shall promptly notify Williams of any matters
                  pertaining to any damage or impending damage to or loss of
                  System that are actually known to it and that could reasonably
                  be expected to adversely affect the System.

         9.3.     PRECAUTIONS.

                  Winstar shall take all reasonable precautions against any
                  damage proximately caused by Winstar to the System or to
                  fibers used or owned by Williams or third parties.

         9.4.     USE OF EQUIPMENT.

                  Neither party shall use, or allow others to use, equipment,
                  technologies, or methods of operation that adversely affect
                  the Williams Network or the System or the permitted use of the
                  Williams Network or the System by Williams or third parties or
                  their respective Fibers, equipment, or facilities associated
                  therewith. If Winstar uses equipment, technologies, and
                  methods of operation that are collectively either in accord
                  with Williams' practices or generally accepted industry
                  standards, Williams shall have the burden of demonstrating
                  that Winstar has breached the requirements of the preceding
                  sentence.

         9.5.     LIENS.

                  Winstar shall not, directly or indirectly, cause any part of
                  the System to become subject to any mechanic's lien,
                  materialman's lien, vendor's lien, or any similar lien whether
                  by operation of law or otherwise. If Winstar becomes aware
                  that it has breached its obligations under this Section, it
                  shall promptly: (a) notify Williams in writing, (b) cause such
                  lien to be discharged and released of record without cost to
                  Williams, and (c) indemnify Williams against all costs and
                  expenses (including reasonable attorneys' fees and court costs
                  at trial and on appeal) incurred in discharging and releasing
                  such lien.


                                       17
<PAGE>

10.      TERM

         10.1.    AGREEMENT TERM.

                  The term of this Agreement and the IRUs granted under it shall
                  begin on the New IRU Commencement Date and shall end twenty
                  (20) years from the Acceptance Date for the last of the System
                  Segments to be delivered (the "Term").

         10.2.    SERVICE ORDER TERM.

                  Each Service Order placed under this Agreement shall have its
                  own Service Order Term, as indicated on such Service Order. At
                  the end of the Service Order Term for any Service Order, such
                  Service Order shall continue on a month-to-month basis
                  ("Extension Period") unless either party gives written notice
                  to the other that such Service Order shall not be continued,
                  such notice to be delivered at least sixty (60) calendar days
                  before the end of the Service Order Term, or if during the
                  Extension Period, then upon at least thirty (30) calendar
                  days' prior written notice. Charges to Winstar, as set forth
                  in this Agreement, for Services provided by Williams during
                  the Service Order Term shall continue to apply to Winstar
                  throughout any Extension Period, unless modified pursuant to
                  the terms of this Agreement.

         10.3.    EFFECT OF TERMINATION.

                  No termination of this Agreement, the Capacity IRU or the
                  Winstar IRU shall affect the rights or obligations of any
                  party hereto:

                  (a)      With respect to any payment or the handling of a
                           disputed payment hereunder for services rendered
                           under this Agreement during the Term; or

                  (b)      Pursuant to Articles 15, 16, 17, 18, 20, 23 and 24.1
                           entitled Indemnification; Limitation of Liability;
                           Insurance; Taxes and Governmental Fees; Confidential
                           Information; Remedies and Dispute Resolution; and
                           Rules of Construction, respectively.

         10.4     TRANSITION.

                  (a) By the date occurring one hundred eighty (180) days prior
                  to the end of the Term, Williams and Winstar shall met and
                  negotiated in good faith a plan to transition all of Winstar's
                  traffic off of the Winstar Fibers and the Circuits on which
                  the Capacity is provided ("Transition Period"). Winstar shall
                  continue payment of the Monthly Payment for all Winstar Fibers
                  and all Circuits on which its traffic is present for so long
                  as its traffic is carried, provided that Winstar shall prepay
                  any charges for the Winstar Fibers or the Circuits if the
                  parties have agreed to extend such usage beyond the Term.


                                       18
<PAGE>


                 (b) If because of Winstar's default, the Agreement is
                 terminated before the end of the Term, Winstar may request a
                 "Transition Period" of up to one hundred twenty (120) days
                 during which to move its traffic from the Winstar Fibers and
                 the Circuits on which the Capacity is provided. If Winstar
                 wishes a Transition Period after termination due to Winstar's
                 default, Winstar must provide notice to Williams within
                 twenty-four (24) hours of receipt of the notice of default from
                 Williams along with payment in full in immediately available
                 funds for the total of the Monthly Payments for the entire
                 Transition Period.

11.      OPERATION. MAINTENANCE, AND REPAIR OF THE SYSTEM

         11.1.    ROUTINE MAINTENANCE.

                  During the Term, Williams shall perform all required
                  maintenance and repair work that:

                  (a)      is specifically identified as Routine Maintenance in
                           Exhibit I; or

                  (b)      has aggregate Costs incurred as a result of any
                           single event or multiple, closely related events less
                           than or equal to ten thousand dollars ($10,000.00) at
                           no additional cost to Winstar. "Routine Maintenance"
                           means the work specifically identified as Routine
                           Maintenance in Exhibit I, provided that Routine
                           Maintenance excludes work for which Winstar is
                           obligated to reimburse Williams for all or a portion
                           of the Costs incurred pursuant to other Articles of
                           this Agreement.

         11.2.    NON-ROUTINE MAINTENANCE.

                  Winstar shall pay its Pro Rata Share of Williams' direct Costs
                  of non-Routine Maintenance of the System in excess of ten
                  thousand dollars ($10,000), if the Cost of such work relating
                  to any single event or multiple related events is greater than
                  ten thousand dollars ($10,000.00).

         11.3.    SUBCONTRACTORS.

                  Williams may subcontract provisioning, testing, maintenance,
                  repair, restoration, relocation, or other operational and
                  technical services it is obligated to provide hereunder or may
                  have the underlying facility owner or its contractor perform
                  such obligations. Such subcontracting shall not relieve
                  Williams of any obligations under this Agreement.

         11.4.    WINSTAR EQUIPMENT.

                  Williams' maintenance and repair obligations under this
                  Agreement shall not include maintenance, repair or replacement
                  of Winstar Equipment.


                                       19
<PAGE>


         11.5     ACCESS TO SYSTEMS.

                  Winstar shall not access any physical part of any System
                  Segment without the prior written consent of Williams, and
                  then only upon the terms and conditions specified by Williams.

12.      RELOCATION

         12.1.    RELOCATION.

                  If, Williams determines for bona fide operational reasons, or
                  is required by a third party acting pursuant to condemnation
                  or similar authority or by a governmental entity, to relocate
                  all or any portion of such System Segment or any of the
                  facilities used or required in providing Winstar with the
                  Winstar IRU, Williams shall, to the extent practicable,
                  provide Winstar sixty (60) days' prior notice of any such
                  relocation and shall proceed with such relocation. Williams
                  shall have the right to direct such relocation, including the
                  right to determine the extent of, the timing of, and methods
                  to be used for such relocation, provided that any such
                  relocation:

                  (a)      Shall be constructed and tested in accordance with
                           the specifications and requirements set forth in this
                           Agreement and applicable Exhibits;

                  (b)      Shall not result in a materially adverse change to
                           the operations, performance, Connecting Points with
                           the network of Winstar, or end points of the System
                           Segment; and

                  (c)      Shall not unreasonably interrupt service on the
                           affected System Segment.

                  For purposes of this Section, a Williams' relocation shall be
                  for bona fide operational reasons if it is undertaken in good
                  faith (i) to settle or avoid a bona fide threatened or filed
                  condemnation action or order by a governmental authority to
                  relocate, (ii) to reduce the likelihood of physical damage to
                  the System, (iii) as the result of a Force Majeure Event, or
                  (iv) for other operational reasons to which Winstar has
                  consented, provided that Winstar shall not unreasonably
                  withhold such consent. Williams shall use reasonable efforts
                  to contest any exercise of condemnation authority that would
                  require a relocation that would require Winstar to reimburse
                  Williams pursuant to this Article 12.

         12.2.    COST OF RELOCATION.

                  Unless such relocation is necessitated by a breach of
                  Williams' obligations under this Agreement or is undertaken by
                  Williams for any reason other than those reasons set forth in
                  Section 12.1 above, Winstar shall reimburse Williams for the
                  Costs incurred in the same manner and to the same extent as is
                  set forth for reimbursement of Costs in this Agreement.


                                       20
<PAGE>

         12.3.    UPDATED AS-BUILT DRAWINGS.

                  At Winstar's written request, Williams shall deliver to
                  Winstar updated as-built drawings with respect to a relocated
                  portion of the System Segment within the later of one-hundred
                  eighty (180) days following the completion of such relocation
                  or thirty (30) days after receipt of Winstar's request.

13.      INVOICING AND PAYMENT

         13.1.    MONTHLY PAYMENT.

                  (a)      Winstar shall pay Williams the Monthly Payments
                           during the Term as set forth in Section 3.1 and in
                           accordance with Exhibit K.

                  (b)      The first payment shall be due and payable upon
                           Winstar's execution of this Agreement. If any payment
                           made under the Interim Agreement has not been used by
                           the obligations under the Interim Agreement, and such
                           payment under the Interim Agreement had been made in
                           cash, it shall be applied and Winstar shall receive a
                           credit toward the first payment in the amount of
                           the unused portion of any payment under the Interim
                           Agreement.

                  (c)      Each additional Monthly Payment shall be due and
                           payable thereafter on the same day of the month as
                           the date of execution of this Agreement; provided
                           however, that if any such date is not a day on which
                           banks in New York are open for business (each, a
                           "Business Day"), then the payment due thereon shall
                           be paid on the next Business Day.

                  (c)      The Network IRU described in this Agreement shall not
                           become effective until Williams' receipt of the
                           initial payment described above.

                  (d)      All other amounts due hereunder shall be due and
                           payable thirty (30) days from Winstar's receipt of
                           the invoice ("Due Date"). Winstar agrees to remit
                           payment to Williams at the remittance address set
                           forth in the applicable invoice.

         13.2.    FORM OF PAYMENT.

                  Winstar shall pay the Monthly Payment and any other amount due
                  hereunder by wire transfer of immediately available funds via
                  Automated Clearinghouse ("ACH") or wire transfer to Williams
                  Communications, LLC in care of Bank One, Chicago, Illinois,
                  ABA #071000013, Account #52-87235 or such other bank or
                  account as Williams may in writing direct Customer to remit
                  payment pursuant to the notice provisions of this Agreement.
                  Customer acknowledges and understands that all charges are
                  computed exclusive of any applicable taxes and additional
                  charges expressly provided herein. Such additional charges
                  shall be paid by Customer in addition to all other charges
                  provided for herein.


                                       21
<PAGE>

         13.3.    DISPUTED CHARGES.

                  (a)      Winstar may only dispute charges for Additional
                           Services or Other Services. Winstar shall pay
                           undisputed charges when such payments are due under
                           this Agreement. Winstar may withhold payment of
                           particular charges that Winstar disputes in good
                           faith and for which it promptly gives written notice
                           to Williams, stating the details of such dispute. The
                           parties shall promptly refer such matter to dispute
                           resolution in accordance with Section 24. If Winstar
                           withholds any disputed charges and such charges are
                           ultimately determined to be proper and payable to
                           Williams, Winstar shall ultimately pay such charges
                           to Williams plus interest at the Prime Rate from the
                           date such charges were originally due until the date
                           such charges are paid. No payment dispute shall be
                           grounds for Williams to withhold or diminish the
                           quality or quantity of any of the connectivity and
                           services provided hereunder.

                  (b)      Termination of this Agreement as suspension of
                           Services as set forth in this Section shall not
                           affect Winstar's obligation to pay for the Services.

         13.4.    LATE INTEREST.

                  If either Williams or Winstar fails to make any payment of any
                  undisputed amount due and payable under this Agreement when
                  due, such amounts shall accrue interest, from the date such
                  payment is due until paid, including accrued interest, at the
                  Prime Rate.

         13.5.    ADJUSTMENTS.

                  Williams may make corrections to its invoices to reflect
                  undercharges only for the period of two (2) years following
                  the Due Date of each invoice, or two (2) years following the
                  date the corresponding service is rendered, whichever is
                  later.

         13.6.    WILLIAMS' RIGHT TO ASSURANCE.

                  (a)      If at any time there is a material adverse change in
                           Winstar's creditworthiness or a material adverse
                           change in Winstar's financial position, then in
                           addition to any other remedies available to Williams,
                           Williams may elect, in its sole discretion, to demand
                           reasonable assurance of payment from Winstar,
                           including among others the posting of a deposit and
                           executing an agreement with Williams regarding the
                           use of any such deposit ("Deposit Agreement"), such
                           Deposit Agreement to be in form and substance
                           acceptable to both Parties.

                  (b)      A material adverse change in Winstar's
                           creditworthiness shall include, but not be limited
                           to: (i) Winstar's default of its obligations to
                           Williams under this Agreement; (ii) failure of
                           Winstar to make full payment of charges due hereunder
                           on or before the Due Date on two (2) or more
                           occasions


                                       22
<PAGE>

                           during any period of twelve (12) or fewer months;
                           (iii) acquisition of Winstar (whether in whole or by
                           majority or controlling interest) by an entity which
                           is insolvent ,or which owes past due amounts to
                           Williams or any Williams affiliate, or which is a
                           materially greater credit risk than Winstar.

                  (c)      A material adverse change in Winstar's financial
                           position shall include, but not be limited to a
                           decrease in net worth or working capital of five
                           percent (5%) or greater during any calendar quarter.

                  (d)      In the event of a Williams demand for assurance of
                           payment, if Winstar has not provided Williams with
                           assurance satisfactory to Williams within ten (10)
                           calendar days of Williams' notice of demand for such
                           assurance, then, in addition to any other remedies
                           available to Williams, Williams shall have the
                           option, in its sole discretion, to exercise one or
                           more of the following remedies: (i) cause the start
                           of any Service described in any previously executed
                           Service Order to be delayed pending receipt of such
                           financial statements or of the satisfactory
                           assurance; or (ii) decline to accept a Service Order
                           or other requests from Winstar to provide Service.

14.      DISCLAIMER OF WARRANTIES

         14.1.    PARTIES.

                  EXCEPT AS SPECIFICALLY SET FORTH IN THIS AGREEMENT, THE
                  PARTIES MAKE NO WARRANTY TO EACH OTHER OR ANY OTHER ENTITY,
                  WHETHER EXPRESS, IMPLIED OR STATUTORY, AS TO THE
                  MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OF ANY
                  FIBERS, THE SYSTEM, THE TELECOMMUNICATIONS SERVICES, ANY OTHER
                  SERVICES OR ANY ADDITIONAL SERVICES PROVIDED HEREUNDER OR
                  DESCRIBED HEREIN, OR AS TO ANY OTHER MATTER, ALL OF WHICH
                  WARRANTIES ARE HEREBY EXPRESSLY EXCLUDED AND DISCLAIMED.

         14.2.    FACILITY OWNERS/LENDERS.

                  NO FACILITY OWNERS/LENDERS HAVE MADE ANY REPRESENTATION OR
                  WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, TO WINSTAR
                  CONCERNING WILLIAMS, THE WINSTAR FIBERS, THE CABLE, OR THE
                  SYSTEM OR AS TO ANY OF THE MATTERS SET FORTH IN SECTION 14.1.


                                       23
<PAGE>


15.      INDEMNIFICATION

         15.1.    INDEMNIFICATION.

                  Each party ("Indemnitor") shall indemnify, defend, protect,
                  and hold harmless the other party, its employees, members,
                  managers, officers, agents, contractors, Facility
                  Owners/Lenders, and Affiliates (collectively and individually,
                  "Claimant"), from and against any and all Losses resulting or
                  arising from, relating to or incurred in connection with:

                  (a)      The Indemnitor's failure to observe or perform its
                           duties or obligations to third parties (e.g., duties
                           or obligations to its customers);

                  (b)      The Indemnitor's infringement or misappropriation of
                           Intellectual Property Rights of any third party;

                  (c)      The death or bodily injury of any agent, employee,
                           customer, business invitee or any other person to the
                           extent caused by the tortious conduct of the
                           Indemnitor;

                  (d)      The damage, loss or destruction of any real or
                           tangible personal property to the extent caused by
                           the tortious conduct of the Indemnitor;

                  (e)      Fines, penalties or other amounts payable due to the
                           Indemnitor's violation of applicable laws or
                           regulation; and

                  (f)      Any Claim, demand, charge, action, cause of action,
                           or other proceeding asserted against the Claimant but
                           resulting from an act or omission of the Indemnitor
                           in its capacity as an employer of a person.

         15.2.    THIRD PARTY CLAIMS.

                  With respect to third-party claims, the following procedures
                  shall apply:

                  (a)      Promptly after receipt of notice of the commencement
                           or threatened commencement of any civil, criminal,
                           administrative, or investigative action or proceeding
                           involving a Claim in respect of which the Claimant
                           will seek indemnification pursuant to this Article
                           15, the Claimant will notify the Indemnitor of such
                           Claim in writing. No failure to so notify the
                           Indemnitor will relieve the Indemnitor of its
                           obligations under this Agreement except to the extent
                           that its ability to defend such Claim is materially
                           prejudiced by such failure. Within fifteen (15)
                           calendar days following receipt of written notice
                           from the Claimant relating to any Claim, but no later
                           than ten (10) calendar days before the date on which
                           any response to a complaint or summons is due, the
                           Indemnitor will notify the Claimant in writing if the
                           Indemnitor elects to assume control of the defense
                           and settlement of that Claim (a "Notice of
                           Election").


                                       24
<PAGE>


                  (b)      If the Indemnitor delivers a Notice of Election
                           relating to any Claim within the required notice
                           period, the Indemnitor shall be entitled to have sole
                           control over the defense and settlement of such
                           Claim; provided that (i) the Claimant shall be
                           entitled to observe the defense of such Claim and to
                           employ counsel at its own expense to observe the
                           defense of such Claim, and (ii) the Indemnitor shall
                           obtain the prior written approval, not to be
                           unreasonably withheld or delayed, of the Claimant
                           before ceasing to defend against such Claim or
                           entering into any settlement of such Claim. After the
                           Indemnitor has delivered a Notice of Election
                           relating to any Claim in accordance with the
                           preceding paragraph, the Indemnitor shall not be
                           liable to the Claimant for any legal expenses
                           incurred by the Claimant in connection with the
                           defense of that Claim. In addition, the Indemnitor
                           shall not be required to indemnify the Claimant for
                           any amount paid or payable by the Claimant in the
                           settlement of any Claim for which the Indemnitor has
                           delivered a timely Notice of Election if such amount
                           was agreed to without the written consent of the
                           Indemnitor.

                  (c)      If the Indemnitor does not deliver a Notice of
                           Election relating to any Claim within the required
                           notice period or after delivering a Notice of
                           Election fails to defend the Claim, the Claimant
                           shall have the right to defend the Claim in such
                           manner as it may deem appropriate. The Indemnitor
                           shall promptly reimburse the Claimant for all
                           reasonable costs and expenses of such defense.

         15.3.    INDEMNIFICATION OF PROVIDERS.

                  Winstar shall indemnify and hold harmless Williams its
                  employees, members, managers, officers, agents, contractors,
                  facility owners/lenders, affiliates and any Third Party
                  Service Providers, acting in such capacity, from and against
                  all Losses arising out of or relating to the content of any
                  transmission by Winstar, including Claims relating to any
                  violation or alleged violation of export control laws or other
                  laws or failure to comply with Winstar's obligations as set
                  forth in Sections 27.4 and 27.5.

         15.4.    WINSTAR CUSTOMERS.

                  Winstar shall indemnify and hold Williams its employees,
                  members, managers, officers, agents, contractors, facility
                  owners/lenders, affiliates, acting in such capacity, harmless
                  from and against all Losses arising out of or relating to the
                  use of the Winstar Fibers by any Winstar customer.


                                       25

<PAGE>

16.      LIMITATION OF LIABILITY

         16.1.    GENERAL INTENT.

                  Subject to the specific provisions of this Article 16, it is
                  the intent of the Parties that each party shall be liable to
                  the other party for any actual damages incurred by the
                  non-breaching party as a result of the breaching party's
                  failure to perform its obligations in the manner required by
                  this Agreement.

         16.2.    LIABILITY RESTRICTIONS.

                  (a)      IN NO EVENT, WHETHER IN CONTRACT OR IN TORT
                           (INCLUDING BREACH OF WARRANTY, NEGLIGENCE AND STRICT
                           LIABILITY IN TORT), SHALL A PARTY BE LIABLE FOR
                           INDIRECT, CONSEQUENTIAL, EXEMPLARY, PUNITIVE OR
                           SPECIAL DAMAGES EVEN IF SUCH PARTY HAS BEEN ADVISED
                           OF THE POSSIBILITY OF SUCH DAMAGES IN ADVANCE.

                  (b)      Subject to Subsection (c), below, each party's total
                           liability to the other, whether in contract or in
                           tort (including breach of warranty, negligence and
                           strict liability in tort) shall be limited to two
                           hundred million dollars ($200,000,000).

                  (c)      The limitation set forth in Subsections (b), above,
                           shall not apply with respect to: (i) third-party
                           Claims subject to indemnification pursuant to the
                           Agreement; or (ii) fees due and owing under this
                           Agreement at the time of the Claim.

                  (d)      For the purposes of this Section 16.2 all amounts
                           payable  or paid to third parties in connection with
                           Claims that are eligible for indemnification pursuant
                           to this Agreement shall be deemed direct damages.

         16.3.    RELEASED PARTIES.

                  Neither party shall have any recourse of any kind against any
                  Released Party or any assets of a Released Party in respect of
                  any Claim that is not directly or indirectly caused by the
                  Released Party, it being expressly agreed and understood that
                  no liability whatsoever shall attach to or be incurred by any
                  Released Party in respect of any Claim under or by reason of
                  this Agreement or any other instrument, arrangement or
                  understanding relating to the Winstar IRU, the System, the
                  Capacity IRU, the Telecommunications Services, the Other
                  Services or Additional Services, except to the extent such
                  Claim is directly or indirectly caused by the Released Party.
                  Each party waives all such recourse to the extent set forth in
                  this Section on behalf of its successors, assigns, and any
                  entity claiming by, through, or under such party.


                                       26
<PAGE>

17.      INSURANCE

         During the Term, the parties shall each obtain and maintain not less
         than the insurance requirements in accordance with Exhibit C.

18.      TAXES AND GOVERNMENTAL FEES

         18.1.    PAYMENT BY WINSTAR.

                  Winstar shall timely report and pay any and all sales, use,
                  income, gross receipts, excise, transfer, ad valorem, or other
                  taxes, and any and all franchise fees or similar fees, if any,
                  assessed against it due to its ownership of the Network IRU,
                  its use of the Winstar Fibers, or use of the Capacity IRU
                  including the provision of services over the Winstar Fibers,
                  its use of any other part of the System, or its use of
                  facilities connected to the Winstar Fibers. Notwithstanding
                  the preceding sentence, if Winstar provides Williams with a
                  valid resale or other exemption certificate, Williams shall
                  not charge Winstar any taxes exempted by the resale of other
                  exemption certificate.

         18.2     PAYMENT BY WILLIAMS.

                  Subject to Section 18.1 above, Williams shall timely report
                  and pay any and all sales, use, income, gross receipts,
                  excise, transfer, ad valorem or other taxes, and any and all
                  franchise fees or similar fees assessed against it due to its
                  construction, ownership or use of the System, provided that
                  Winstar shall reimburse Williams for its Pro-Rata Share of
                  property taxes (including ad valorem, use, property, or
                  similar taxes, franchise fees, or assessments that are based
                  on the value of property or of a property right) attributable
                  to the System, including taxes based on the value, operation,
                  or existence of the System.

         18.3     REIMBURSEMENT.

                  If Williams is assessed for any taxes or fees (a) related to
                  Winstar's ownership of the Network IRU, Winstar's use of or
                  rights in the Capacity or Winstar Fibers, or (b) that Winstar
                  is obligated to pay pursuant to Sections 18.1 or 18.2,
                  Winstar shall reimburse Williams for any payment of such
                  taxes or fees within thirty (30) days of receipt of Williams'
                  invoice.

         18.4     COOPERATION.

                  The parties shall cooperate in any contest of any taxes or
                  fees so as to avoid, to the extent reasonably possible,
                  prejudicing the interests of the other party.

         18.5     SERVICES.

                  If any sales taxes, value added taxes or similar charges or
                  impositions are assessed against Williams after, or as a
                  result of, Winstar's use of Telecommunications


                                       27
<PAGE>
                  Services, any Other Services or the Additional Services by any
                  local, state, national, international, public or quasi-public
                  governmental entity or foreign government or its political
                  subdivision, to the extent Winstar has not provided a resale
                  or other exemption certificate, Winstar shall be solely
                  responsible for and shall pay such taxes, charges or
                  impositions and shall hold Williams harmless from any
                  liability or expense associated with such taxes, charges or
                  impositions. If Williams incurs any tax or charge levied to
                  support the Universal Service Fund contemplated by Section 254
                  the Communications Act of 1934 as amended, 47 U.S.C. Section
                  254, or its state or municipal equivalent, Winstar shall be
                  solely responsible for and agrees to reimburse Williams for
                  any such tax or charge.

19.      NOTICE

         Unless otherwise provided in this Agreement, all notices and
         communications concerning this Agreement shall be in writing and
         addressed to the other party as follows, or at such other address as
         may be designated in writing to the other party:

<Table>
<S>                                                         <C>
          IF TO WINSTAR:                                     IF TO WILLIAMS:
               WINSTAR WIRELESS, INC.                               WILLIAMS COMMUNICATIONS, INC.
               685 THIRD AVENUE                                     ONE WILLIAMS CENTER, SUITE 26-5
               NEW YORK, NY 10017                                   TULSA, OKLAHOMA 74172
               ATTN: EVP, GENERAL COUNSEL                            ATTN: CONTRACT ADMINISTRATION

          WITH A COPY TO:                                      WITH A COPY TO:

               WINSTAR WIRELESS, INC.                               WILLIAMS COMMUNICATIONS, INC.
               2545 HORSE PEN ROAD                                  ONE WILLIAMS CENTER, SUITE 4100
               HERNDON, VIRGINIA 22171                              TULSA, OKLAHOMA 74172
               ATTN: VP, COMMERCIAL AND LEGAL OPERATIONS             ATTN: GENERAL COUNSEL
</Table>

                  Unless otherwise provided herein, notices shall be hand
                  delivered, sent by registered or certified U.S. Mail, postage
                  prepaid, or by commercial overnight delivery service, and
                  shall be deemed served or delivered to the addressee or its
                  office when received at the address for notice specified above
                  when hand delivered, on the day after being sent when sent by
                  overnight delivery service, three (3) days after deposit in
                  the mail when sent by U.S. mail or, in the case of invoices,
                  upon the Due Date (as defined in the Telecommunications
                  Services Purchase Provision).

20.      CONFIDENTIALITY

         20.1.    CONFIDENTIAL INFORMATION.

                  Williams and Winstar each acknowledge that they may be
                  furnished with, receive, or otherwise have access to
                  information of or concerning the other party that such


                                       28
<PAGE>

                  party considers to be confidential, proprietary, a trade
                  secret or otherwise restricted. As used in this Agreement and
                  subject to the exclusions set forth in Section 20.3.
                  "Confidential Information" means all information, in any form,
                  furnished or made available directly or indirectly by one
                  party (the "Disclosing Party") to the other (the "Receiving
                  Party") that (i) concerns the operations, facilities, plans,
                  affairs and businesses of the Disclosing Party, the financial
                  affairs of the Disclosing Party, and the relations of the
                  Disclosing Party with its customers, employees and service
                  providers, or (ii) is marked confidential, restricted,
                  proprietary, or with a similar designation. The terms and
                  conditions of this Agreement shall be deemed Confidential
                  Information obligation.

         20.2.    OBLIGATIONS.

                  (a)      Each party's Confidential Information shall remain
                           the property of that party except as expressly
                           provided otherwise by the other provisions of this
                           Agreement. Each party shall each use at least the
                           same degree of care, but in any event no less than a
                           reasonable degree of care, to prevent unauthorized
                           disclosure of Confidential Information as it employs
                           to avoid unauthorized disclosure of its own
                           information of a similar nature. Except as otherwise
                           permitted hereunder, the parties may disclose such
                           information (A) to their respective directors,
                           officers, managers, employees, agents, contractors
                           and consultants (collectively, "Representatives") and
                           (B) entities performing services required hereunder
                           only where: (i) use of such entity is authorized
                           under this Agreement, (ii) such disclosure is
                           necessary or otherwise naturally occurs in that
                           entity's scope of responsibility, and (iii) the
                           entity agrees in writing to assume the obligations
                           described in this Section 20.2. Any disclosure to
                           such entity shall be under substantially the same
                           confidentiality terms and conditions as provided
                           herein.

                  (b)      Each party shall take reasonable steps to ensure that
                           its (and its Affiliates') Representatives comply with
                           this Section 20.2. In the event of any disclosure or
                           loss of, or inability to account for, any
                           Confidential Information of the Disclosing Party, the
                           Receiving Party shall promptly, at its own expense:
                           (i) notify the Disclosing Party in writing; (ii) take
                           such actions as may be necessary and cooperate in all
                           reasonable respects with the Disclosing Party to
                           minimize the violation and any damage resulting
                           therefrom.

                  (c)      Either party may disclose the terms and conditions of
                           this Agreement to any third party that (i) has
                           expressed a bona fide interest in consummating a
                           significant financing, merger or acquisition
                           transaction or other corporate transaction between
                           the third party and such party, (ii) has a reasonable
                           ability (financial or otherwise) to consummate such
                           transaction, and (iii) has executed a nondisclosure
                           agreement that includes within its scope the terms
                           and conditions of this Agreement and also includes a
                           procedure to limit the extent of copying and
                           distribution thereof. Each party shall


                                       29
<PAGE>


                 endeavor to delay the disclosure of the terms and conditions of
                 this Agreement until the status of discussions concerning such
                 transaction warrants such disclosure. In addition, either party
                 (or either party's Affiliates) may disclose the terms and
                 conditions of this Agreement as such party deems appropriate to
                 prepare for IPOs or major corporate transactions. Any
                 disclosure to such entity shall be substantially under the same
                 confidentiality terms and conditions as provided herein.

         20.3.    EXCLUSIONS.

                  "Confidential Information" shall exclude any particular
                  information that the Receiving Party can demonstrate:

                  (a)      At the time of disclosure, was in the public domain
                           or in the rightful possession of the Receiving Party;

                  (b)      After disclosure, is published or otherwise becomes
                           part of the public domain through no fault of the
                           Receiving Party;

                  (c)      Was received after disclosure from a third party who
                           had a lawful right to disclose such information to
                           the Receiving Party without any obligation to
                           restrict its further use or disclosure;

                  (d)      Was independently developed by the Receiving Party
                           without reference to Confidential Information of the
                           Disclosing Party; or

                  (e)      Was required to be disclosed to satisfy a legal
                           requirement of a competent government body; provided
                           that, immediately upon receiving such request and to
                           the extent that it may legally do so, the Receiving
                           Party advises the Disclosing Party promptly and prior
                           to making such disclosure in order that the
                           Disclosing Party may interpose an objection to such
                           disclosure, take action to assure confidential
                           handling of the Confidential Information, or take
                           such other action as it deems appropriate to protect
                           the Confidential Information.

         20.4.    No IMPLIED RIGHTS.

                  Nothing contained in this Section shall be construed as
                  obligating a party to disclose its Confidential Information to
                  the other party, or as granting to or conferring on a party,
                  expressly or impliedly, any rights or license to the
                  Confidential Information of the other party.

         20.5.    COMMUNICATION WITH FCC.

                  Communications by either party with the FCC regarding the
                  subject matter of this Agreement shall require the other's
                  prior written approval.


                                       30
<PAGE>

21.      DEFAULT

                  Subject to Williams' right of accelerated termination as set
                  forth in Exhibit K, a party shall not be in material breach of
                  this Agreement unless and until the other party provides it
                  written notice of default and the non-performing party has
                  failed to cure within thirty (30) days after receipt of such
                  notice. Any event of default may be waived in writing at the
                  non-defaulting party's option. Upon the failure of a party to
                  timely cure its material breach hereunder within the
                  applicable cure period, the non-defaulting party shall have
                  the right to (i) terminate this Agreement or (ii) subject to
                  the terms of Article 24, pursue any legal remedies it may have
                  under applicable law or principles of equity relating to such
                  breach.

22.      THE TERMINATION OF THIS AGREEMENT BY WINSTAR PURSUANT TO THE FOREGOING
         SHALL NOT RELIEVE WINSTAR OF ITS OBLIGATION TO PAY ANY AMOUNTS OWING ON
         THE CONTRACT PRICE OR OTHER AMOUNTS OWING TO WILLIAMS WHICH ACCRUED OR
         WERE INCURRED PRIOR TO THE DATE OF SUCH TERMINATION.

23.      FORCE MAJEURE

         23.1.    EXCUSABLE DELAY.

                  Neither Williams nor Winstar shall be in default under this
                  Agreement as a result of any delay in its performance (other
                  than a failure to make payments when due) caused by any
                  elements of nature or acts of God, fire, explosion, vandalism,
                  power outage, earthquake, flood or lightning; any civil or
                  military authority; by national emergency, insurrection,
                  rebellion, revolution, riot, civil disorders, war or act of
                  terrorism; by cable cuts; or any other cause beyond the
                  reasonable control of such party (collectively, "Force Majeure
                  Events"); provided, however, that (i) the non-performing party
                  is without fault in causing such default or delay, and (ii)
                  such default or delay could not have been prevented by
                  reasonable precautions and cannot reasonably be circumvented
                  by the non-performing party through the use of alternate
                  sources (e.g., other suppliers of telecommunications services
                  or capacity), workaround plans or other means, including means
                  contemplated by applicable disaster recovery processes or
                  procedures).

         23.2.    NOTICE AND REMEDY.

                  In such event the non-performing party shall be excused from
                  further performance or observance of the obligation(s) so
                  affected for as long as such circumstances prevail and such
                  party continues to use commercially reasonable efforts to
                  recommence performance or observance whenever and to whatever
                  extent possible without delay. The non-performing party shall
                  immediately notify the other party by telephone (to be
                  confirmed in writing within two (2) business days of the
                  inception of such delay) and describe at a reasonable level of
                  detail the


                                       31
<PAGE>

                  Force Majeure Event causing such delay and the expected
                  duration of the Force Majeure Event. The non-performing party
                  will provide the other party prompt written notice of the
                  cessation or termination of the Force Majeure Event.

24.      REMEDIES AND DISPUTE RESOLUTION

         24.1.    (a) DISPUTE RESOLUTION.

                  Any dispute between the Parties arising out of or relating to
                  this Agreement, the interpretation of any provision hereof or
                  the performance of Williams or Winstar shall be resolved as
                  provided in this Article 24. Notwithstanding the foregoing,
                  Winstar shall be obligated to make all Monthly Payments
                  without regard to the dispute process set forth herein.

                  (b) Cumulative Remedies.

                  Except as otherwise expressly provided herein, all remedies
                  provided for in this Agreement shall be cumulative and in
                  addition to and not in lieu of any other remedies available to
                  either party at law, in equity or otherwise.

         24.2.    INFORMAL DISPUTE RESOLUTION.

                  (a)      Prior to the initiation of any litigation, the
                           parties shall first attempt to resolve their dispute
                           at the chief executive officers level. Each Party's
                           CEO will meet to discuss the dispute, which may be in
                           person or by teleconference. This informal dispute
                           resolution requirement shall not delay the
                           institution of formal proceedings past any statute of
                           limitations expiration or for more than thirty (30)
                           days.

                  (b)      This Section 24.2 shall not be construed to prevent a
                           party from instituting, and a party is authorized to
                           institute, formal proceedings earlier to avoid the
                           expiration of any applicable limitations period, or
                           to preserve a superior position with respect to other
                           creditors or as provided in Exhibit K.

         24.3.    CONTINUED PERFORMANCE.

                  Each party agrees to continue performing its obligations under
                  this Agreement while any dispute is being resolved except to
                  the extent the issue in dispute precludes performance.

         24.4.    IMMEDIATE INJUNCTIVE RELIEF.

                  The only circumstance in which disputes between the parties
                  shall not be subject to the provisions of Section 24.2 is
                  where a party, in good faith, determines that a


                                       32
<PAGE>

                  temporary restraining order or other injunctive relief is its
                  only appropriate and adequate remedy. If a party seeks
                  immediate injunctive relief and does not prevail in
                  substantial part, that party shall pay the other party's costs
                  and attorneys' fees to the extent incurred in responding to or
                  challenging the request for immediate injunctive relief.

25.      GENERAL

         25.1.    RULES OF CONSTRUCTION.

                  (a)      The captions or headings in this Agreement are
                           strictly for convenience and shall not be considered
                           in interpreting this Agreement or as amplifying or
                           limiting any of its content. Words in this Agreement
                           that import the singular connotation shall be
                           interpreted as plural, and words that import the
                           plural connotation shall be interpreted as singular,
                           as the identity of the parties or objects referred to
                           may require. References to "person" or "entity" each
                           include natural persons and legal entities, including
                           corporations, limited liability companies,
                           partnerships, sole proprietorships, business
                           divisions, unincorporated associations, governmental
                           entities, and any entities entitled to bring an
                           action in, or that are subject to suit in an action
                           before, any state or federal court of the United
                           States.

                  (b)      Unless expressly defined herein, words having
                           well-known technical or trade meanings shall be so
                           construed.

                  (c)      Except as set forth to the contrary herein, any right
                           or remedy of Williams or Winstar shall be cumulative
                           and without prejudice to any other right or remedy,
                           whether contained herein or not.

                  (d)      Nothing in this Agreement is intended to provide any
                           legal rights to anyone not an executing party of this
                           Agreement except under the indemnification and
                           insurance provisions and except that (i) the Released
                           Parties shall have the benefit of Section 16.3,
                           25.2(a) and 25.5(a) and (ii) the Facility
                           Owners/Lenders shall be entitled to rely on and have
                           the benefit of Sections 14.2 and 25.5(b).

                  (e)      This Agreement has been fully negotiated between
                           Williams and Winstar.

                  (f)      In the event of a conflict between the provisions of
                           this Agreement and those of any Exhibit, the
                           provisions of the Exhibits shall prevail and this
                           Agreement shall be corrected accordingly.

                  (g)      Except as otherwise set forth herein, for the purpose
                           of this Agreement the normal standards of performance
                           within the telecommunications industry in the
                           relevant market shall be the measure of whether a
                           party's performance is reasonable and timely.


                                       33

<PAGE>


                  (h)      Except as the context otherwise indicates, all
                           references to Exhibits, Articles, Sections,
                           Subsections, Clauses, and Paragraphs refer to
                           provisions of this Agreement.

                  (i)      The failure of either Williams or Winstar to enforce
                           any of the provisions of this Agreement, or the
                           waiver thereof in any instance, shall not be
                           construed as a general waiver or relinquishment on
                           its part of any such provision, but the same shall
                           nevertheless be and remain in full force and effect.

                  (j)      This Agreement shall be governed by and construed in
                           accordance with the domestic laws of the State of New
                           York without reference to its choice of law
                           principles. All disputes referred to the statute of
                           limitations and the remedies for any wrongs that may
                           be found shall be governed by the laws of such state.
                           If a proceeding is brought for the enforcement of
                           this Agreement or because of any alleged or actual
                           dispute, breach, default or misrepresentation in
                           connection with any of the provisions of this
                           Agreement, the prevailing party shall be entitled to
                           recover reasonable attorneys' fees and other actual
                           and reasonable costs and expenses incurred in such
                           action or proceeding in addition to any other relief
                           to which such party may be entitled.

                  (k)      If any term, covenant or condition in this Agreement
                           shall, to any extent, be invalid or unenforceable in
                           any respect under the laws governing this Agreement,
                           the remainder of this Agreement shall not be affected
                           thereby, and each term, covenant or condition of this
                           Agreement shall be valid and enforceable to the
                           fullest extent permitted by law.

                  (1)      The parties acknowledge and agree that: (i) the
                           payment deductions ("Payment Deductions") set forth
                           in Sections 8.4. (collectively, the "Deduction
                           Section") shall not limit Williams' liability or
                           serve as a sole or exclusive remedy for Williams'
                           default under any portion of this Agreement; (ii)
                           Winstar may seek any other rights or remedies it may
                           have against Williams for any default hereunder;
                           (iii) the Deduction Section does not modify or
                           otherwise limit any other term or condition of this
                           Agreement; and (iv) Winstar's compliance with the
                           Deduction Section shall not constitute a breach of
                           the Payment Terms. Williams hereby waives any rights
                           it may have to use the Deduction Section as a claim
                           or defense against any other provision in this
                           Agreement.

         25.2.    ASSIGNMENT.

                  (a)      Except to the extent permitted by Section 25.2(d),
                           neither party may, or shall have the power to, assign
                           this Agreement (and, in the case of Section
                           24.2(a)(v), below, pledge or grant a security
                           interest in this Agreement) the


                                       34
<PAGE>

                           Winstar IRU or the Capacity IRU or delegate such
                           party's obligations hereunder without the prior
                           written consent of the other except to:

                           (i)      An entity that acquires all or substantially
                                    all of the assets of such party,

                           (ii)     Any Affiliate,

                           (iii)    A successor in a merger or acquisition of
                                    such party,

                           (iv)     An entity that acquires less than
                                    substantially all of the assets of such
                                    Party provided that the entity has been
                                    determined to be financially solvent by
                                    mutual agreement or the assignment has been
                                    approved by the court, or

                           (v)      In connection with any financing.

                           Provided, further, that a party may assign the
                           entirety of its rights and obligations under this
                           Agreement, or the Winstar IRU or the Capacity IRU,
                           individually, with the other party's consent, not to
                           be unreasonably withheld or delayed. In any case,
                           such consent shall not be withheld if the assignee
                           meets certain objective conditions such as credit
                           worthiness and other similar considerations and the
                           assignee agrees in writing to become bound by this
                           Agreement. If the potential assignor tenders a
                           commercially reasonable form of unconditional
                           guarantee of the potential assignee's performance
                           signed by the potential assignor and if such form
                           shall become legally binding upon the potential
                           assignor upon execution and delivery by the
                           non-assigning party, then the potential assignee
                           shall be deemed creditworthy unless it is insolvent
                           or subject to protection under the bankruptcy laws.
                           The rights of assignment expressed in this Section
                           24.2(a) are subject to the restrictions set forth in
                           Section 24.2(e), below:

                  (b)      Notwithstanding the foregoing, no assignment or other
                           transfer of this Agreement shall be effective without
                           the written agreement of the assignee to be bound by
                           the terms and conditions of this Agreement including
                           the indemnification provisions and limitations on
                           liability and recourse provision set forth in this
                           Agreement (including those benefiting the Released
                           Parties).

                  (c)      [intentionally omitted.]


                  (d)      The provisions of Section 25.2(a) notwithstanding,
                           Williams may assign some or all of its rights and
                           obligations hereunder to State Street Bank and Trust
                           Company of Connecticut, National Association, or its
                           successors, in connection with a financing by
                           Williams of construction of its fiber optic network.
                           In addition, State Street Bank and Trust Company of
                           Connecticut, National Association, or its successors,
                           may further assign


                                       35
<PAGE>

                           this Agreement as collateral for such financing. If
                           Williams makes an assignment pursuant to this
                           Subsection 25.2(d), Williams (or its assignee
                           pursuant to an assignment made under the other
                           provisions of this Section 25.2) shall guarantee
                           performance of the assignee's obligations.

                  (e)      Except in connection with an assignment of this
                           Agreement as provided herein, until the third (3rd)
                           anniversary of the Acceptance Date of any System
                           Segment, Winstar shall not sell the dark fiber, but
                           may place optronics in such System Segment and resell
                           capacity, wavelengths, windows or lambdas in any
                           increment. After such three (3) year period, Winstar
                           may convey an interest in the dark fiber provided
                           that Winstar shall serve as the sole point of contact
                           with Williams and no party receiving such interest
                           shall have any contract rights against or be in
                           privity of contract with Williams as a result of such
                           conveyance.

                  (f)      This Agreement and the rights and obligations under
                           this Agreement (including the limitations on
                           liability and recourse set forth in this Agreement
                           benefiting the other party and the Released Parties)
                           shall be binding upon and shall inure to the benefit
                           of Williams and Winstar and their respective
                           permitted successors and assigns.

                  (g)      Neither the provisions of this Article nor any other
                           provisions of this Agreement shall limit the ability
                           of any Facility Owners/Lenders or of any Released
                           Parties to assign their rights under this Agreement
                           and such Facility Owners/Lenders and Released Parties
                           may assign their rights hereunder at any time and
                           from time to time without the consent of, notice to,
                           or any other action by any other entity. The
                           provisions of this Agreement benefiting the Facility
                           Owners/Lenders and Released Parties shall inure to
                           the benefit of such entities and their respective
                           Affiliates, successors, and assigns.

                  (h)      Notwithstanding any presumptions under applicable
                           state law that a change in control of a party
                           constitutes an assignment of an agreement, a change
                           in control of a party, not made for purposes of
                           circumventing restrictions on assignment or of
                           depriving the other party of rights under this
                           Agreement, shall not be deemed an assignment for
                           purposes of this Agreement.

         25.3.    RELATIONSHIP OF THE PARTIES.

                  The relationship between Williams and Winstar shall not be
                  that of partners, agents, or joint venturers for one another,
                  and nothing contained in this Agreement shall be deemed to
                  constitute a partnership or agency agreement between them for
                  any purposes, including federal income tax purposes. Williams
                  and Winstar, in performing any of their obligations hereunder,
                  shall be


                                       36
<PAGE>

                  independent contractors or independent parties and shall
                  discharge their contractual obligations at their own risk.

         25.4.    PROHIBITION ON IMPROPER PAYMENTS.

                  Neither party shall use any funds received under this
                  Agreement for illegal or otherwise "improper" purposes.
                  Neither party shall pay any commission, fees or rebates to any
                  employee of the other party. If either party has reasonable
                  cause to believe that one of the provisions in this Article
                  has been violated, it, or its representative, may audit the
                  books and records of the other party for the sole purpose of
                  establishing compliance with such provisions.

         25.5.    ENTIRE AGREEMENT; AMENDMENT; EXECUTION.

                  (a)      This Agreement constitutes the entire and final
                           agreement and understanding between Williams and
                           Winstar with respect to the subject matter hereof and
                           supersedes all prior agreements (oral or written)
                           relating to the subject matter hereof, which are of
                           no further force or effect (including, without
                           limitation, the IRU Agreement between Winstar
                           Wireless, Inc. and Williams Communications, Inc.
                           dated December 17, 1998, (Long-Haul) and all
                           amendments, clarifications and modifications thereto,
                           and the Standstill Agreement among Winstar Wireless,
                           Inc., Winstar Communications, Inc. and Williams dated
                           May 8, 2001, as amended, and the Winstar Services
                           Agreement between Williams and Winstar GoodNet, dated
                           July 16, 1998, Contract Number 98R0675.00, provided
                           that any undisputed payment obligations accruing
                           prior to the Effective Date, shall be due and owing
                           under the terms of this Agreement). The Exhibits
                           referred to herein are integral parts hereof and are
                           made a part of this Agreement by reference.

                  (b)      This Agreement may only be amended, modified, or
                           supplemented by an instrument in a single writing
                           executed by duly authorized representatives of
                           Williams and Winstar. No such amendment,
                           modification, or supplement shall result in any
                           modification of (i) any indemnity benefiting any
                           Facility Owners/Lenders or their respective
                           Affiliates or (ii) any limitation of liability or
                           recourse benefiting any Released Parties that is
                           adverse to such Released Parties.

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

                  (d)      This Agreement may be duly executed and delivered by
                           a party by execution and facsimile delivery of the
                           signature page of a counterpart to the other party,
                           provided that, if delivery is made by facsimile, the
                           executing party shall promptly deliver a complete
                           counterpart that it has executed to the other party.


                                       37
<PAGE>

                  (e)      Unless otherwise expressly permitted in this
                           Agreement, Williams shall not make any changes to the
                           Exhibits or Schedules attached hereto that may have a
                           material adverse impact on the performance or
                           usability of the Telecommunications Services,
                           Additional Services or Other Services without
                           Winstar's prior written consent.

         25.6.    PUBLIC DISCLOSURES.

                  All media releases, public announcements, and public
                  disclosures relating to this Agreement or the subject matter
                  of this Agreement, including promotional or marketing
                  material, but not including announcements intended solely for
                  internal distribution or disclosures to the extent required to
                  meet legal or regulatory requirements shall be coordinated
                  with and shall be subject to approval by both parties prior to
                  release.

26.      REPRESENTATIONS, WARRANTIES AND COVENANTS

         26.1.    REPRESENTATIONS AND WARRANTIES.

                  In addition to any other representations and warranties
                  contained in this Agreement, each party hereto represents and
                  warrants to the other that:

                  (a)      It has the requisite corporate power to enter into,
                           execute, deliver, and perform its obligations under
                           this Agreement;

                  (b)      It has taken all requisite corporate action to
                           approve the execution, delivery, and performance of
                           this Agreement;

                  (c)      This Agreement constitutes a legal, valid and binding
                           obligation enforceable against such party in
                           accordance with its terms;

                  (d)      Its execution of and performance under this Agreement
                           shall not violate any applicable existing
                           regulations, rules, statutes, or court orders of any
                           local, state, or federal government agency, court, or
                           body;

                  (e)      It is not subject to any contractual or other
                           obligation that would prevent it from entering into
                           this relationship; and

                  (f)      It has not offered or provided any inducements in
                           violation of law or the other party's policies, of
                           which it has been given notice, in connection with
                           this Agreement.

         26.2.    ADDITIONAL WILLIAMS COVENANTS.

                  Excluding services provided by third parties other than
                  Williams' subcontractors, Williams covenants that
                  Telecommunications Services, Additional Services, and Other
                  Services shall be provided to Winstar in accordance with the
                  technical


                                       38
<PAGE>

                  specifications set forth in the applicable service schedule.
                  Williams further covenants that it shall use commercially
                  reasonable efforts under the circumstances to remedy any
                  delays, interruptions, omissions, mistakes, accidents or
                  errors in the Telecommunications Services, Additional Services
                  or Other Services provided hereunder and to restore such
                  Telecommunications Services or Other Services to compliance
                  with the terms hereof.

         26.3.    INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS.

                  Each party represents, warrants and covenants to the other
                  that it shall perform its responsibilities under this
                  Agreement in a manner that does not infringe, or constitute an
                  infringement or misappropriation of, any Intellectual Property
                  Rights of any third party.

27.      USE OF TELECOMMUNICATIONS AND OTHER SERVICES

         27.1.    CONDITION TO PROVISION OF SERVICES.

                  As a condition to provision of the Services by Williams,
                  Winstar warrants that the Telecommunications Services or Other
                  Services shall not be used for any unlawful purpose and that
                  more than ten percent (10%) of the transmissions will be
                  interstate transmissions. The parties represent to each other
                  that this Agreement, to the extent it is subject to FCC
                  regulation, is an inter-carrier agreement not subject to the
                  filing requirements of Section 211 (a) of the Communications
                  Act of 1934, as amended.

         27.2.    INTRASTATE INTEREXCHANGE SERVICES.

                  Winstar may use any interexchange service provided under this
                  Agreement including any service provided by means of a
                  Backbone Agreement only if such interexchange service is used
                  for carrying inter-state (as defined by the FCC)
                  telecommunications (i.e., telecommunications subject to the
                  jurisdiction of the Federal Communications Commission).
                  Williams and its Affiliates shall not be obligated to make
                  available Telecommunications Services, Additional Services, or
                  other interexchange service on a Circuit with end points
                  within a single state or service on a Circuit which
                  originates/terminates at points both of which are situated
                  within a single state unless Winstar represents in writing
                  that such interexchange service or Circuits shall be used to
                  carry inter-state telecommunications (as defined by the FCC).

         27.3.    WINSTAR RESPONSIBILITIES.

                  Winstar has sole responsibility for installation, testing and
                  operation of facilities, services and equipment ("Winstar
                  Facilities") other than those specifically provided by
                  Williams as part of the Telecommunications Services or Other
                  Services as described in a Service Order. In no event will the
                  untimely installation or non-operation of Winstar Facilities
                  relieve Winstar of its obligation


                                       39
<PAGE>

                  to pay charges for the Service or Other Service after the
                  Requested Start Date as set forth in the Service Order.

         27.4.    CONSENTS.

                  As between the parties, Winstar shall be responsible for all
                  arrangements with copyright holders, music licensing
                  organizations, performers' representatives or other parties
                  for necessary authorizations, clearances or consents with
                  respect to transmission contents.

         27.5.    RESTRICTION OF TRANSMISSIONS.

                  Winstar will not transmit content, nor permit its customers to
                  transmit content that violates applicable law or carries an
                  unreasonable risk of leading to criminal, civil or
                  administrative proceedings or investigations against Williams
                  or Winstar.

         27.6     COMPLIANCE WITH REGULATIONS.

                  If the FCC, any state regulatory body, or any court, in each
                  case having competent jurisdiction, determines that any
                  provision of this Agreement violates any applicable rules,
                  policies, or regulations, both parties shall reasonably
                  cooperate to immediately bring this Agreement into compliance,
                  consistent with the intent of this Agreement.

         27.7     RELATED AGREEMENTS.

                  On August 27, 2001, Winstar and Williams executed the Option
                  Agreement and the Amendment to the Wireless IRU. Winstar and
                  Williams agreed then and affirm now that the execution of the
                  Option Agreement was consideration for the other party to
                  execute the amendment to the Wireless IRU, and the execution
                  of the amendment to the Wireless IRU was consideration for the
                  other party to execute the Option Agreement. Winstar and
                  Williams further agree that, if the option under the Option
                  Agreement is exercised, the Wireless IRU, as amended, and the
                  this Agreement are intended to be, and shall be treated for
                  all purposes as, a single integrated agreement. Accordingly,
                  in the event that Williams becomes the subject of a case under
                  the United States Bankruptcy Code, Williams agrees that the
                  Wireless IRU, as amended, and the this Agreement shall be
                  treated as a single integrated agreement for purposes of 11
                  U.S.C. 365.

         27.7     REASONABLENESS, CONSENTS AND APPROVALS.

                  (a)      Where this Agreement requires a party to assist or
                           cooperate, such requirement shall not be interpreted
                           to require materially more than a commercially
                           reasonable level of effort (i.e. the standard
                           applicable will not be "best efforts" or "exhausting
                           all available means").


                                       40
<PAGE>

                  (b)      Except where expressly provided as being in the sole
                           discretion of a party, where agreement, approval,
                           acceptance, consent, or similar action by either
                           party is required under this Agreement, such action
                           shall not be unreasonably delayed or withheld. An
                           approval or consent given by a party under this
                           Agreement shall not relieve the other party from
                           responsibility for complying with the requirements of
                           this Agreement, nor shall it be construed as a waiver
                           of any rights under this Agreement, except as and to
                           the extent otherwise expressly provided in such
                           approval or consent.


                                       41
<PAGE>

         IN WITNESS WHEREOF and in confirmation of their consent to the terms
and conditions contained in this Agreement and intending to be legally bound
hereby, Williams and Winstar have executed and delivered this Agreement as of
the dates set forth below.



WINSTAR WIRELESS, INC.                       WILLIAMS COMMUNICATIONS, LLC.




BY:                                          BY: /s/ BRYON J. DANCER
    -------------------------------              -------------------------------

NAME:                                        NAME:   Bryon J. Dancer
     ------------------------------                -----------------------------

TITLE:                                       TITLE:  V.P. Business Development
      -----------------------------                 ----------------------------

DATE:                                        DATE:   8-27-01
       ----------------------------                 ----------------------------



                                       42