<PAGE>


                                                                   EXHIBIT 10.90


                               SECURITY AGREEMENT

                                   dated as of

                                 April 23, 2001

                                      among

                          WILLIAMS COMMUNICATIONS, LLC,

                      WILLIAMS COMMUNICATIONS GROUP, INC.,

                           THE SUBSIDIARY LOAN PARTIES

                                       and

                              BANK OF AMERICA, N.A.
                             as ADMINISTRATIVE AGENT

<PAGE>


<Table>
<S>         <C>                                                            <C>
SECTION 1.  Definitions.....................................................  1
SECTION 2.  Grant of Transaction Liens...................................... 11
SECTION 3.  General Representations and Warranties.......................... 14
SECTION 4.  Further Assurances; General Covenants........................... 16
SECTION 5.  Accounts........................................................ 18
SECTION 6.  Recordable Intellectual Property................................ 19
SECTION 7.  Investment Property............................................. 19
SECTION 8.  Controlled Deposit Accounts..................................... 20
SECTION 9.  Cash Collateral Accounts........................................ 21
SECTION 10. Operation of Collateral Accounts................................ 21
SECTION 11. Remedies upon Event of Default.................................. 23
SECTION 12. Application of Proceeds......................................... 24
SECTION 13. Fees and Expenses; Indemnification.............................. 26
SECTION 14. Authority to Administer Collateral.............................. 28
SECTION 15. Limitation on Duty in Respect of Collateral..................... 28
SECTION 16. General Provisions Concerning the Administrative Agent.......... 29
SECTION 17. Termination of Transaction Liens; Release of Collateral......... 30
SECTION 18. Additional Secured Obligations.................................. 31
SECTION 19. Notices......................................................... 32
SECTION 20. No Implied Waivers; Remedies Not Exclusive...................... 33
SECTION 21. Successors and Assigns.......................................... 33
SECTION 22. Amendments and Waivers.......................................... 33
SECTION 23. Choice of Law................................................... 33
SECTION 24. Waiver of Jury Trial............................................ 33
SECTION 25. Severability.................................................... 34
SECTION 26. Additional Lien Grantors........................................ 34
SECTION 27. Effectiveness................................................... 34
</Table>


                                        2
<PAGE>


SCHEDULES:

       SCHEDULE 1   Equity Interests in Restricted Subsidiaries Owned by
                    Original Lien Grantors

       SCHEDULE 2   Investment Property (other than Equity Interests in
                    Subsidiaries) Owned by Original Lien Grantors

       SCHEDULE 3   Broadband Media Assets

EXHIBITS:

       EXHIBIT A    Security Agreement Supplement

       EXHIBIT B    Perfection Certificate

       EXHIBIT C    Deposit Account Control Agreement

       EXHIBIT D    Issuer Account Control Agreement

       EXHIBIT E    Securities Account Control Agreement

       EXHIBIT F    Copyright Security Agreement

       EXHIBIT G    Patent Security Agreement

       EXHIBIT H    Trademark Security Agreement



                                        3
<PAGE>


                          SECURITY AGREEMENT

         AGREEMENT dated as of April 23, 2001 among WILLIAMS COMMUNICATIONS,
LLC, WILLIAMS COMMUNICATIONS GROUP, INC., THE SUBSIDIARY LOAN PARTIES and BANK
OF AMERICA, N.A., as Administrative Agent.

         WHEREAS, the Borrower and Holdings have entered into the Credit
Agreement described in Section 1 hereof, pursuant to which the Borrower has
borrowed funds and intends to continue to borrow funds for the purposes set
forth therein;

         WHEREAS, the Borrower and Holdings are willing to secure their
respective obligations under the Credit Agreement by granting, and causing the
Subsidiary Loan Parties to grant, Liens on their respective assets as specified
herein to the Administrative Agent as provided in the Collateral Documents;

         WHEREAS, as of the date hereof, Holdings ceases to be a subsidiary of
The Williams Companies, Inc.;

         NOW, THEREFORE, in consideration of the foregoing and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         SECTION 1. Definitions.

         (a) Terms Defined in Credit Agreement. Terms defined in the Credit
Agreement and not otherwise defined in Sections 1(b) or 1(c) have, as used
herein, the respective meanings provided for therein.

         (b) Terms Defined in UCC. As used herein, each of the following terms
(i) if it is defined in both the Current UCC and the Revised UCC, has the
meaning specified in the Current UCC until the UCC Revision Date and the meaning
specified in the Revised UCC on and after the UCC Revision Date or (ii) if it is
defined in the Revised UCC but not in the Current UCC, has the meaning specified
in the Revised UCC at all times:

Term                           Current UCC            Revised UCC
----                           -----------            -----------
Account                        9-106                  9-102
Authenticate                   not defined            9-102
Chattel Paper                  9-105                  9-102
Deposit Account                not defined            9-102
Document                       9-105                  9-102
Entitlement Holder             8-102                  8-102


<PAGE>



Entitlement Order              8-102                  8-102
Equipment                      9-109                  9-102
Financial Asset                8-102 & 103            8-102 & 103
General Intangibles            9-106                  9-102
Instrument                     9-105                  9-102
Inventory                      9-109                  9-102
Investment Property            9-115                  9-102
Letter-of-Credit Right         not defined            9-102
Payment Intangible             not defined            9-102
Record                         not defined            9-102
Securities Account             8-501                  8-501
Securities Intermediary        8-102                  8-102
Security                       8-102 & 103            8-102 & 103
Security Entitlement           8-102                  8-102
Supporting Obligations         not defined            9-102

         (c) Additional Definitions. The following additional terms, as used
herein, have the following meanings:

         "Borrower" means Williams Communications, LLC, a Delaware limited
liability company.

         "Cash Collateral Account" has the meaning set forth in Section 9
hereof.

         "Cash Distributions" means dividends, interest and other distributions
and payments (including proceeds of liquidation, sale or other disposition)
received in cash upon or with respect to any Collateral.

         "Collateral" means all property, whether now owned or hereafter
acquired, on which a Lien is granted or purports to be granted to the
Administrative Agent pursuant to the Collateral Documents. When used with
respect to a specific Lien Grantor, the term "Collateral" means all its property
on which such a Lien is granted or purports to be granted.

         "Collateral Accounts" means the Cash Collateral Accounts, the
Controlled Deposit Accounts and the Controlled Securities Accounts.

         "Collateral Documents" means this Agreement, the Security Agreement
Supplements, the Control Agreements, the Intellectual Property Security
Agreements and all other supplemental or additional security agreements, control
agreements, or similar instruments delivered pursuant to the Loan Documents.



                                        2
<PAGE>


         "Contingent Secured Obligation" means, at any time, any Secured
Obligation (or portion thereof) that is contingent in nature or unliquidated at
such time, including any Secured Obligation that is:

                  (i) an obligation to reimburse a bank for drawings not yet
         made under a letter of credit issued by it;

                  (ii) an obligation under a Hedging Agreement to make payments
         that cannot be quantified at such time;

                  (iii) any other obligation that is contingent in nature at
         such time; provided that contingent obligations under general
         indemnification provisions (such as Section 10.03 of the Credit
         Agreement) and the like as to which no claim is pending or reasonably
         foreseeable shall not be treated as Contingent Secured Obligations for
         purposes of administration of this Agreement; and

                  (iv) an obligation to provide collateral to secure any of the
         foregoing types of obligations.

         "Control" has the following meanings:

                  (a) when used with respect to any Security or Security
         Entitlement, (i) before the applicable UCC Revision Date, the meaning
         specified in Current UCC Section 8-106 and (ii) on and after the
         applicable UCC Revision Date, the meaning specified in Revised UCC
         Section 8-106; and

                  (b) when used with respect to any Deposit Account, the meaning
         specified in Revised UCC Section 9-104.

         "Control Agreement" means any Deposit Account Control Agreement, Issuer
Control Agreement or Securities Account Control Agreement.

         "Controlled Deposit Account" means a Deposit Account (i) that is
subject to a Deposit Account Control Agreement or (ii) as to which the
Administrative Agent is the Depositary Bank's "customer" (as defined in UCC
Section 4-104).

         "Controlled Securities Account" means a Securities Account that (i) is
maintained in the name of a Lien Grantor at an office of a Securities
Intermediary located in the United States of America and (ii) together with all
Financial Assets credited thereto and all related Security Entitlements, is
subject to a Securities Account Control Agreement among such Lien Grantor, the
Administrative Agent and such Securities Intermediary.



                                        3
<PAGE>


         "Copyright License" means any agreement now or hereafter in existence
granting to any Lien Grantor, or pursuant to which any Lien Grantor grants to
any other Person, any right to use, copy, reproduce, distribute, prepare
derivative works, display or publish any records or other materials on which a
Copyright is in existence or may come into existence, including any agreement
identified in Schedule 1 to any Copyright Security Agreement.

         "Copyrights" means all the following: (i) all copyrights under the laws
of the United States or any other country (whether or not the underlying works
of authorship have been published), all registrations and recordings thereof,
all copyrightable works of authorship (whether or not published), and all
applications for copyrights under the laws of the United States or any other
country, including registrations, recordings and applications in the United
States Copyright Office or in any similar office or agency of the United States,
any State thereof or any other country or any political subdivision thereof,
including those described in Schedule 1 to any Copyright Security Agreement,
(ii) all renewals of any of the foregoing, (iii) all claims for, and rights to
sue for, past or future infringements of any of the foregoing, and (iv) all
income, royalties, damages and payments now or hereafter due or payable with
respect to any of the foregoing, including damages and payments for past or
future infringements thereof.

         "Copyright Security Agreement" means a Copyright Security Agreement,
substantially in the form of Exhibit F, executed and delivered by a Lien Grantor
in favor of the Administrative Agent for the benefit of the Secured Parties.

         "Credit Agreement" means the Amended and Restated Credit Agreement
dated as of September 8, 1999 among the Borrower (formerly known as Williams
Communications, Inc.), Holdings, the Lenders party thereto, the Administrative
Agent and The Chase Manhattan Bank, as syndication agent, as amended by
Amendment No. 1 dated as of December 31, 1999, Amendment No. 2 dated as of
December 31, 1999, Amendment and Restatement dated as of September 1, 2000 and
Amendment No. 4 dated as of March 14, 2001, and as the same may hereafter be
further amended from time to time.

         "Current UCC" means the UCC as in effect from time to time before the
UCC Revision Date.

         "Deposit Account Control Agreement" means, with respect to any Deposit
Account of any Lien Grantor, a Deposit Account Control Agreement substantially
in the form of Exhibit C hereto (with any changes the Administrative Agent shall
have approved, which approval shall not be unreasonably withheld) among such
Lien Grantor, the Administrative Agent and the relevant Depositary Bank, set
forth in an Authenticated Record, (i) to the effect that such Depositary Bank
will comply with instructions originated by the Administrative Agent directing


                                        4
<PAGE>


disposition of the funds in such Deposit Account without further consent by such
Lien Grantor and (ii) subordinating to the relevant Transaction Lien all claims
of the Depositary Bank to such Deposit Account (except its right to deduct its
normal operating charges and any uncollected funds previously credited thereto).

         "Depositary Bank" means a bank at which a Controlled Deposit Account is
maintained.

         "Eligible Transferee" means (i) a Receivables Subsidiary, or (ii) any
other Person which is not a Subsidiary of Holdings or the Borrower.

         "Equity Interest" means (i) shares of its capital stock, partnership
interests, membership interests in a limited liability company, beneficial
interests in a trust or other equity ownership interests in a Person, (ii) any
warrant, option or other right to acquire any Equity Interest described in this
definition or (iii) any Security Entitlement in respect of any Equity Interest
described in this definition.

         "Holdings" means Williams Communications Group, Inc., a Delaware
corporation.

         "Intellectual Property" means any and all (i) Patents, (ii) Patent
Licenses, (iii) Trademarks, (iv) Trademark Licenses, (v) Copyrights and (vi)
Copyright Licenses, and all rights in or under any of the foregoing.

         "Intellectual Property Filing" means (i) with respect to any Patent,
Patent License, Trademark or Trademark License, the filing of the applicable
Patent Security Agreement or Trademark Security Agreement with the United States
Patent and Trademark Office, together with an appropriately completed
recordation form, and (ii) with respect to any Copyright or Copyright License,
the filing of the applicable Copyright Security Agreement with the United States
Copyright Office, together with an appropriately completed recordation form, in
each case sufficient to record the Transaction Lien granted to the
Administrative Agent in such Recordable Intellectual Property.

         "Intellectual Property Security Agreement" means a Copyright Security
Agreement, a Patent Security Agreement or a Trademark Security Agreement.

         "Issuer Control Agreement" means an Issuer Control Agreement
substantially in the form of Exhibit D (with any changes that the Administrative
Agent shall have approved, which changes shall not be unreasonably withheld).

         "Lien Grantors" means the Borrower, Holdings and the Subsidiary Loan
Parties.



                                        5
<PAGE>


         "Mobile Goods" shall mean portable electric generators; construction
equipment; repair equipment and tools; test equipment; items stored as spares;
spooled cable; items shipped for replacement, repair, diagnostic testing or
refund; items removed for salvage having a value of less than 5% of their
original book value; property perfected on a nationwide basis (including wheeled
vehicles, watercraft and aircraft) as long as it remains within the United
States; and other items having an aggregate book value of no more than
$1,000,000.

         "Moody's" means Moody's Investors Services, Inc.

         "Non-Contingent Secured Obligation" means at any time any Secured
Obligation (or portion thereof) that is not a Contingent Secured Obligation at
such time.

         "Original Lien Grantor" means any Lien Grantor that grants a Lien on
any of its assets hereunder on the Initial Collateral Date.

         "own" refers to the possession of sufficient rights in property to
grant a security interest therein as contemplated by UCC Section 9-203, and
"acquire" refers to the acquisition of any such rights.

         "Patent License" means any agreement now or hereafter in existence
granting to any Lien Grantor, or pursuant to which any Lien Grantor grants to
any other Person, any right with respect to any Patent or any invention now or
hereafter in existence, whether patentable or not, whether a patent or
application for patent is in existence on such invention or not, and whether a
patent or application for patent on such invention may come into existence or
not, including any agreement identified in Schedule 1 to any Patent Security
Agreement.

         "Patents" means (i) all letters patent and design letters patent of the
United States or any other country and all applications for letters patent or
design letters patent of the United States or any other country, including
applications in the United States Patent and Trademark Office or in any similar
office or agency of the United States, any State thereof or any other country or
any political subdivision thereof, including those described in Schedule 1 to
any Patent Security Agreement, (ii) all reissues, divisions, continuations,
continuations in part, revisions and extensions of any of the foregoing, (iii)
all claims for, and rights to sue for, past or future infringements of any of
the foregoing and (iv) all income, royalties, damages and payments now or
hereafter due or payable with respect to any of the foregoing, including damages
and payments for past or future infringements thereof.


                                        6
<PAGE>


         "Patent Security Agreement" means a Patent Security Agreement,
substantially in the form of Exhibit G, executed and delivered by a Lien Grantor
in favor of the Administrative Agent for the benefit of the Secured Parties.

         "Payroll Accounts" means any accounts owned by a Lien Grantor, so long
as the only amounts on deposit therein are applied to pay payroll expenses of
Holdings and its Subsidiaries payable in the ordinary course of business.

         "Perfection Certificate" means, with respect to any Lien Grantor, a
certificate substantially in the form of Exhibit B, completed and supplemented
with the schedules contemplated thereby to the reasonable satisfaction of the
Administrative Agent, and signed by an officer of such Lien Grantor.

         "Permitted Collateral Sale" has the meaning set forth in Section 17(b)
hereof.

         "Permitted Liens" means (i) the Transaction Liens, (ii) Liens on a
Specified Security securing a Permitted Specified Security Hedging Transaction
with respect to such Specified Security and (iii) any other Liens on the
Collateral permitted to be created or assumed or to exist pursuant to Section
6.02 of the Credit Agreement.

         "Pledged", when used in conjunction with any type of asset, means at
any time an asset of such type that is included (or that creates rights that are
included) in the Collateral at such time.

         "Pledged Equity Interests Permitted Liens" has the meaning set forth in
Section 3(d).

         "Post-Petition Interest" means any interest that accrues after the
commencement of any case, proceeding or other action relating to the bankruptcy,
insolvency or reorganization of the Borrower (or would accrue but for the
operation of applicable bankruptcy or insolvency laws), whether or not such
interest is allowed or allowable as a claim in any such proceeding.

         "Proceeds" means all proceeds of, and all other profits, products,
rents or receipts, in whatever form, arising from the collection, sale, lease,
exchange, assignment, licensing or other disposition of, or other realization
upon, any Collateral, including all claims of the relevant Lien Grantor against
third parties for loss of, damage to or destruction of, or for proceeds payable
under, or unearned premiums with respect to, policies of insurance in respect
of, any Collateral, and any condemnation or requisition payments with respect to
any Collateral.


                                        7
<PAGE>


         "Receivables" means, with respect to any Lien Grantor, all Accounts
owned by it and all other rights, titles or interests which, in accordance with
GAAP would be included in receivables on its balance sheet (including any such
Accounts and/or rights, titles or interests that might be characterized as
Chattel Paper, Instruments or General Intangibles under the Uniform Commercial
Code in effect in any jurisdiction), in each case arising from the sale, lease,
exchange or other disposition of Inventory, and all of such Lien Grantor's
rights to any goods, services or other property related to any of the foregoing
(including returned or repossessed goods and unpaid seller's rights of
rescission, replevin, reclamation and rights to stoppage in transit), and all
collateral security and supporting obligations of any kind given by any Person
with respect to any of the foregoing.

         "Recordable Intellectual Property" means each (i) Patent, (ii) Patent
License, (iii) Trademark, (iv) Trademark License, (v) Copyright and (vi)
Copyright License, which is of material importance to the conduct of the
business of any Lien Grantor or otherwise has material economic value to a Lien
Grantor by virtue of existing or prospective revenues from the licensing thereof
and/or prosecution of claims for infringement thereof.

         "Related Transferred Rights" means (i) Transferred Receivables, (ii)
rights to payment and collections in respect of such Transferred Receivables,
(iii) security interests or Liens and property subject thereto purporting to
secure or guarantee payment of such Transferred Receivables, (iv) guarantees,
letters of credit, acceptances, insurance and other arrangements from time to
time supporting or securing payment of such Transferred Receivables, (v) all
invoices, documents, books, records and other information with respect to such
Transferred Receivables or the obligors thereon, (vi) with respect to any such
Transferred Receivables, the transferee's interest in the product (including
returned product), the sale of which by such transferee gave rise to such
Transferred Receivables and (vii) all Proceeds of the items described in the
foregoing clauses.

         "Release Conditions" means the occurrence of the following conditions
for terminating all the Transaction Liens:

                  (i) all Commitments under the Credit Agreement shall have
         expired or been terminated;

                  (ii) all Non-Contingent Secured Obligations shall have been
         paid in full; and

                  (iii) no Contingent Secured Obligation shall remain
         outstanding.

         "Revised Article 9" means revised Article 9 of the Uniform Commercial
Code as set forth in the 1998 Official Text thereof; provided that, when used
with


                                        8
<PAGE>


respect to any jurisdiction on or after the date when revised Article 9 (with or
without local changes therein) first becomes effective in such jurisdiction,
"Revised Article 9" refers to Article 9 as in effect in such jurisdiction from
time to time.

         "Revised UCC" means (i) before the UCC Revision Date, the Uniform
Commercial Code as set forth in the 1998 Official Text thereof and (ii) on and
after the UCC Revision Date, the Uniform Commercial Code as in effect from time
to time in the State of New York.

         "S&P" means Standard & Poor's Rating Services, a division of the McGraw
Hill Companies.

         "Secured Agreement", when used with respect to any Secured Obligation,
refers collectively to each instrument, agreement or other document that sets
forth obligations of the Borrower, obligations of a Restricted Subsidiary and/or
rights of the holder with respect to such Secured Obligation.

         "Secured Obligations" means:

         (a) with respect to the Borrower, all principal of all Loans
outstanding from time to time under the Credit Agreement, all reimbursement
obligations with respect to all Letters of Credit issued from time to time under
the Credit Agreement, all interest (including Post-Petition Interest) on such
Loans and reimbursement obligations, all other amounts now or hereafter payable
by the Borrower pursuant to the Loan Documents, all obligations of the Borrower
designated as additional "Secured Obligations" pursuant to Section 18 and any
renewals, extensions or refundings of any of the foregoing; and

         (b) with respect to any Subsidiary Loan Party, its "Guaranteed
Obligations" under the Subsidiary Guaranty, all obligations of such Subsidiary
Loan Party designated as additional "Secured Obligations" pursuant to Section 18
and any renewals, extensions or refundings of any of the foregoing.

         "Secured Parties" means the permitted holders from time to time of the
Secured Obligations.

         "Securities Account Control Agreement" means, when used with respect to
a Securities Account, a Securities Account Control Agreement substantially in
the form of Exhibit E (with any changes that the Administrative Agent shall have
approved, which approval shall not be unreasonably withheld) among the relevant
Securities Intermediary, the relevant Lien Grantor and the Administrative Agent
to the effect that such Securities Intermediary will comply with Entitlement


                                        9
<PAGE>


Orders originated by the Administrative Agent with respect to such Securities
Account without further consent by the relevant Lien Grantor.

         "Securities Act" has the meaning set forth in Section 3(d) hereof.

         "Security Agreement Supplement" means a Security Agreement Supplement,
substantially in the form of Exhibit A, signed and delivered to the
Administrative Agent for the purpose of adding a Restricted Subsidiary as a
party hereto pursuant to the Credit Agreement and/or adding additional property
to the Collateral, whether as a result of a Collateral Event or otherwise.

         "Trademark License" means any agreement now or hereafter in existence
granting to any Lien Grantor, or pursuant to which any Lien Grantor grants to
any other Person, any right to use any Trademark, including any agreement
identified in Schedule 1 to any Trademark Security Agreement.

         "Trademarks" means: (i) all trademarks, trade names, corporate names,
company names, business names, fictitious business names, trade styles, service
marks, logos, brand names, trade dress, prints and labels on which any of the
foregoing have appeared or appear, package and other designs, and all other
source or business identifiers, and all general intangibles of like nature, and
the rights in any of the foregoing which arise under applicable law, (ii) the
goodwill of the business symbolized thereby or associated with each of them,
(iii) all registrations and applications in connection therewith, including
registrations and applications in the United States Patent and Trademark Office
or in any similar office or agency of the United States, any State thereof or
any other country or any political subdivision thereof, including those
described in Schedule 1 to any Trademark Security Agreement, (iv) all renewals
of any of the foregoing, (v) all claims for, and rights to sue for, past or
future infringements of any of the foregoing and (vi) all income, royalties,
damages and payments now or hereafter due or payable with respect to any of the
foregoing, including damages and payments for past or future infringements
thereof.

         "Trademark Security Agreement" means a Trademark Security Agreement,
substantially in the form of Exhibit H, executed and delivered by a Lien Grantor
in favor of the Administrative Agent for the benefit of the Secured Parties.

         "Transaction Liens" means the Liens granted by the Lien Grantors under
the Collateral Documents.

         "Transferred Receivables" means any Receivables that have been sold,
contributed or otherwise transferred to an Eligible Transferee in connection
with a Permitted Receivables Financing.


                                       10
<PAGE>


         "UCC" means the Uniform Commercial Code as in effect from time to time
in the State of New York; provided that, if perfection or the effect of
perfection or non-perfection or the priority of any Transaction Lien on any
Collateral is governed by the Uniform Commercial Code as in effect in a
jurisdiction other than New York, "UCC" means the Uniform Commercial Code as in
effect from time to time in such other jurisdiction for purposes of the
provisions hereof relating to such perfection, effect of perfection or
non-perfection or priority.

         "UCC Revision Date" means the date when Revised Article 9 first becomes
effective in the State of New York; provided that, if perfection or the effect
of perfection or non-perfection or the priority of any Transaction Lien on any
Collateral is governed by the Uniform Commercial Code as in effect in a
jurisdiction other than New York, "UCC Revision Date" means the date when
Revised Article 9 first becomes effective in such other jurisdiction for
purposes of the provisions hereof relating to such perfection, effect of
perfection or non-perfection or priority. Such provisions often refer to the
relevant date as the "applicable UCC Revision Date".

         (c) Terms Generally. The definitions of terms herein (including those
incorporated by reference to the UCC or to another document) apply equally to
the singular and plural forms of the terms defined. Whenever the context may
require, any pronoun includes the corresponding masculine, feminine and neuter
forms. The words "include", "includes" and "including" shall be deemed to be
followed by the phrase "without limitation". The word "will" shall be construed
to have the same meaning and effect as the word "shall". Unless the context
requires otherwise, (i) any definition of or reference to any agreement,
instrument or other document herein shall be construed as referring to such
agreement, instrument or other document as from time to time amended,
supplemented or otherwise modified (subject to any restrictions on such
amendments, supplements or modifications set forth herein), (ii) any reference
herein to any Person shall be construed to include such Person's successors and
assigns, (iii) the words "herein", "hereof" and "hereunder", and words of
similar import, shall be construed to refer to this Agreement in its entirety
and not to any particular provision hereof, (iv) all references herein to
Sections, Exhibits and Schedules shall be construed to refer to Sections of, and
Exhibits and Schedules to, this Agreement and (v) the word "property" shall be
construed to refer to any and all tangible and intangible assets and properties,
including cash, securities, accounts and contract rights.

         SECTION 2. Grant of Transaction Liens.

         (a) Each Lien Grantor, in order to secure the Secured Obligations,
grants to the Administrative Agent for the benefit of the Secured Parties a
continuing


                                       11
<PAGE>


security interest in all the following property of such Lien Grantor whether now
owned or existing or hereafter acquired or arising and regardless of where
located, subject to the exceptions set forth in Section 2(b):

                  (i) all Accounts;

                 (ii) all Chattel Paper;

                (iii) all Deposit Accounts;

                 (iv) all Documents;

                  (v) all Equipment (other than any Equipment subject to a Lien
         permitted under Section 6.02 (iv), (v) and (x) of the Credit Agreement,
         but only so long as such Lien secures any Indebtedness (including
         Capital Lease Obligations) the proceeds of which have been applied to
         finance the acquisitions and/or construction of such Equipment);

                 (vi) all General Intangibles (including any Equity Interests
         in other Persons that do not constitute Investment Property);

                (vii) all Instruments;

               (viii) all Inventory;

                 (ix) all Investment Property;

                  (x) all Letter-of-Credit Rights;

                 (xi) all books and records (including customer lists, credit
         files, computer programs, printouts and other computer materials and
         records) of such Lien Grantor pertaining to any of its Collateral;

                (xii) such Lien Grantor's ownership interest in (1) its
         Collateral Accounts, (2) all Financial Assets credited to its
         Collateral Accounts from time to time and all Security Entitlements in
         respect thereof, (3) all cash held in its Collateral Accounts from time
         to time and (4) all other money in the possession of the Administrative
         Agent; and

               (xiii) all Proceeds of the Collateral described in the foregoing
         clauses (i) through (xii).

         (b) The Collateral shall not include:


                                       12

<PAGE>


                  (i) any Equity Interests in any Foreign Subsidiary or any
         Unrestricted Subsidiary;

                 (ii) any land or interest in land, including any ground lease,
         easement, right-of-way, license, use or possessory interest in, to or
         under land or water or any underground or underwater ductwork, tunnels,
         vaults, landing points or other structures in, to or under which fiber
         may be installed;

                (iii) any ADP Property;

                 (iv) any assets now or hereafter owned by the Borrower to the
         extent and only to the extent such assets are used solely by the
         Borrower's broadband media unit in its business of providing domestic
         and international transmission of live and non-live media content
         through integrated fiber-optic, satellite and teleport services to
         media content service providers, including any such asset constituting
         the application infrastructure referred to as "MediaXtranet(SM)" and
         those assets listed on Schedule 3; provided that any Specified Security
         shall not be excluded from the Collateral; provided further that in no
         event shall (i) fiber optic cable (including the optic fibers and
         sheathing), (ii) conduit, (iii) regenerator, terminal, splice and
         junction facilities for fiber optic cable, (iv) switching, electronic
         and optronic equipment and software to process signals and light the
         optic fibers ("Signal Equipment"), (v) racks, power, alarm, HVAC and
         other equipment and systems used to operate the Signal Equipment and
         (vi) other equipment, fixtures, inventory, parts and supplies relating
         to the Borrower's national intercity network be excluded from the
         Collateral. As of the Amendment No. 4 Effective Date, substantially all
         of the Borrower's broadband media unit operations are conducted through
         the Borrower's Vyvx Services division and the gross and net plant,
         property and equipment of the Borrower's broadband media unit are
         approximately $189.5 million and $97.0 million, respectively; and

                  (v) any assets subject to a Lien permitted under clauses (iv),
         (v), (viii) and (x) of Section 6.02(a) of the Credit Agreement but only
         if and for so long as the document granting or governing such Permitted
         Lien prohibits the granting of another Lien on such assets.

         (c) With respect to each right to payment or performance included in
the Collateral from time to time, the Transaction Lien granted therein includes
a continuing security interest in (i) any Supporting Obligation that supports
such payment or performance and (ii) any Lien that (x) secures such right to
payment or performance or (y) secures any such Supporting Obligation.



                                       13
<PAGE>


         (d) The Transaction Liens are granted as security only and shall not
subject the Administrative Agent or any other Secured Party to, or transfer or
in any way affect or modify, any obligation or liability of any Lien Grantor
with respect to any of the Collateral or any transaction in connection
therewith.

         (e) Each Secured Party acknowledges that certain Collateral including
customer lists is subject to confidentiality provisions applicable thereto.

         SECTION 3. General Representations and Warranties. Each Original Lien
Grantor represents and warrants that:

         (a) Such Lien Grantor is duly organized or formed, validly existing and
in good standing under the laws of the jurisdiction identified as its
jurisdiction of organization or formation in its Perfection Certificate.

         (b) Schedule 1 lists all Equity Interests in Restricted Subsidiaries
owned directly by such Lien Grantor as of the Initial Collateral Date. On the
Initial Collateral Date, such Lien Grantor shall take such steps as may be
necessary or as may be reasonably requested by the Administrative Agent to cause
the Administrative Agent to have Control of all such Equity Interests which
constitute Securities, including in the case of uncertificated Equity Interests
which constitute Securities by entering into, or causing the relevant Issuer to
enter into, an Issuer Control Agreement and, in the case of certificated Equity
Interests, by delivering all stock certificates evidencing such Equity Interests
(together with duly executed undated stock powers). On any date, the Equity
Interests subject to the Transaction Liens constitute all Equity Interests in
Restricted Subsidiaries owned directly by such Lien Grantor as of such date.

         (c) Schedule 2 lists, as of the Initial Collateral Date, (i) all
Securities owned by such Lien Grantor (except Securities evidencing Equity
Interests in Restricted Subsidiaries, Unrestricted Subsidiaries and Foreign
Subsidiaries) and (ii) all Securities Accounts to which Financial Assets are
credited in respect of which such Lien Grantor owns Security Entitlements.

         (d) All Pledged Equity Interests owned by such Lien Grantor are owned
by it free and clear of any Lien other than (i) the Transaction Liens, (ii) with
respect to any Specified Security, Liens thereon securing a Permitted Specified
Security Hedging Transaction with respect to such Specified Security and (iii)
any tax liens and judgment liens that are Permitted Liens (the Liens described
in clauses (i), (ii) and (iii), collectively, the "Pledged Equity Interests
Permitted Liens"). None of such Pledged Equity Interests is subject to any
option to purchase or similar right of any Person except, with respect to any
Pledged Equity Interest consisting of a Specified Security, any agreement
entered into in order to consummate a Permitted Specified Security Hedging
Transaction with respect to


                                       14
<PAGE>


such Specified Security. Such Lien Grantor is not and will not become a party to
or otherwise bound by any agreement (except the Loan Documents) which restricts
in any manner the rights of any present or future holder of any Pledged Equity
Interest with respect thereto except, with respect to any Pledged Equity
Interest consisting of a Specified Security, any agreement entered into in order
to consummate a Permitted Specified Security Hedging Transaction with respect to
such Specified Security. Each Secured Party acknowledges and agrees that any
disposition of Collateral consisting of securities that have not been registered
under the Securities Act of 1933, as amended, and as from time to time in
effect, and the rules and regulations thereunder (the "Securities Act"), shall
be subject to compliance therewith.

         (e) Such Lien Grantor has good title to all its Collateral (or, in the
case of any Collateral that constitutes an interest in a lease or license, a
good leasehold interest in such Collateral) (subject to exceptions that are, in
the aggregate, not material), free and clear of any Lien other than Permitted
Liens.

         (f) Such Lien Grantor has not performed any acts that might prevent the
Administrative Agent from enforcing any of the provisions of the Collateral
Documents or that would limit the Administrative Agent in any such enforcement.
No financing statement, security agreement, mortgage or similar or equivalent
document or instrument covering all or part of the Collateral owned by such Lien
Grantor is on file or of record in any jurisdiction in which such filing or
recording would be effective to perfect or record a Lien on such Collateral,
except financing statements, mortgages or other similar or equivalent documents
with respect to Permitted Liens. On or after the Initial Collateral Date, no
Collateral owned by such Lien Grantor will be in the possession or under the
Control of any other Person having a claim thereto or security interest therein,
other than pursuant to a Permitted Lien.

         (g) The Transaction Liens on all Collateral owned by such Lien Grantor
(i) have been validly created, (ii) will attach to each item of such Collateral
on the Initial Collateral Date as to each Original Lien Grantor or the date on
which it signs and delivers its first Security Agreement Supplement in the case
of any other Lien Grantor (or, if such Lien Grantor first obtains rights thereto
on a later date, on such later date) and (iii) when so attached, will secure all
the Secured Obligations.

         (h) Such Lien Grantor has delivered a Perfection Certificate to the
Administrative Agent. The information set forth therein is correct and complete
as of the date thereof.

         (i) When UCC financing statements describing the Collateral as set
forth in such Lien Grantor's Perfection Certificate have been filed in the
offices


                                       15
<PAGE>


specified in such Perfection Certificate, the Transaction Liens will constitute
perfected security interests in the Collateral owned by such Lien Grantor to the
extent that a security interest therein may be perfected by filing a financing
statement pursuant to the UCC, prior to all Liens and rights of others therein
except Permitted Liens. When, in addition to the filing of such UCC financing
statements, the applicable Intellectual Property Filings have been made with
respect to such Lien Grantor's Recordable Intellectual Property (including any
future filings required pursuant to Sections 4(a) and 6), the Transaction Liens
will constitute perfected security interests in all right, title and interest of
such Lien Grantor in its Recordable Intellectual Property to the extent that
security interests therein may be perfected by such filings, prior to all Liens
and rights of others therein except Permitted Liens. Except for (i) the filing
of such UCC financing statements, (ii) the stamping of certificates of title
with respect to any motor vehicles and aircrafts, and (iii) such Intellectual
Property Filings, no registration, recordation or filing with any governmental
body, agency or official is required in connection with the execution or
delivery of the Collateral Documents or is necessary for the validity or
enforceability thereof or for the perfection of the Transaction Liens or for the
enforcement of the Transaction Liens.

         (j) Such Lien Grantor has taken, and will continue to take, all actions
necessary under the UCC to perfect its interest in any Accounts or Chattel Paper
purchased or otherwise acquired by it, as against its assignors and creditors of
its assignors. On and after the applicable UCC Revision Date, such Lien Grantor
will also take, and continue to take, all actions necessary under the UCC to
perfect its interest in any Payment Intangibles or promissory notes purchased or
otherwise acquired by it, as against its assignors and creditors of its
assignors.

         (k) Such Lien Grantor's Collateral is insured to the extent required by
the Credit Agreement.

         (l) Solely if such Lien Grantor is the Borrower or Williams Local
Network, Inc., such Lien Grantor is a "Transmitting Utility" (as defined in the
UCC). If such Lien Grantor is not the Borrower or Williams Local Network, Inc.,
such Lien Grantor is not a "Transmitting Utility" (as defined in the UCC).

         SECTION 4. Further Assurances; General Covenants. Each Lien Grantor
covenants as follows:

         (a) Such Lien Grantor will, from time to time, at the Borrower's
expense, execute, deliver, file and record any statement, assignment,
instrument, document, agreement or other paper and take any other action
(including any Intellectual Property Filing and other filing of financing or
continuation statements under the UCC) that from time to time may be reasonably
necessary or desirable, or that the Administrative Agent may reasonably request,
in order to:


                                       16
<PAGE>


                  (i) create, preserve, perfect, confirm or validate the
         Transaction Liens on such Lien Grantor's Collateral;

                 (ii) in the case of Pledged Deposit Accounts and Pledged
         Investment Property, cause the Administrative Agent to have Control
         thereof;

                (iii) enable the Administrative Agent and the other Secured
         Parties to obtain the full benefits of the Collateral Documents; or

                 (iv) enable the Administrative Agent to exercise and enforce
         any of its rights, powers and remedies with respect to any of such Lien
         Grantor's Collateral.

To the extent permitted by applicable law, such Lien Grantor authorizes the
Administrative Agent to execute and file such financing statements or
continuation statements without such Lien Grantor's signature appearing thereon.
Such Lien Grantor agrees that a carbon, photographic, photostatic or other
reproduction of this Agreement or of a financing statement is sufficient as a
financing statement; provided that such reproduction of this Agreement may be
filed as a financing statement only if such Lien Grantor shall have failed to
execute and deliver a UCC-1 financing statement promptly upon request of the
Administrative Agent. Such Lien Grantor constitutes the Administrative Agent its
attorney-in-fact to execute and file all Intellectual Property Filings and other
filings required or so requested for the foregoing purposes, all acts of such
attorney being hereby ratified and confirmed; and such power, being coupled with
an interest, shall be irrevocable until all the Transaction Liens granted by
such Lien Grantor terminate pursuant to Section 17. The Borrower will pay the
actual out-of-pocket costs of any Intellectual Property Filings and any
recording or filing of any financing or continuation statements or other
documents recorded or filed pursuant hereto.

         (b) Such Lien Grantor will not (i) change its name or corporate
structure, (ii) change its location (determined as provided in Revised UCC
Section 9-307) or (iii) except as to Permitted Liens, become bound, as provided
in Revised UCC Section 9-203(d) or otherwise, by a security agreement (except as
a secured party) entered into by another Person, unless it shall have given the
Administrative Agent prior notice thereof and taken such actions as the
Administrative Agent may reasonably request in accordance with Section 4(d).

         (c) Before the applicable UCC Revision Date, such Lien Grantor will not
change (i) the location of its chief executive office or chief place of business
or (ii) the locations where it keeps or holds any Collateral (except Inventory
in


                                       17
<PAGE>


transit from one such location to another and Mobile Goods) from the applicable
locations described in its Perfection Certificate, unless it shall have given
the Administrative Agent prior notice thereof and taken such actions as the
Administrative Agent may reasonably request in accordance with Section 4(d). It
will not in any event change the location of any Collateral owned by it if such
change would cause the Transaction Lien on such Collateral to lapse or cease to
be perfected.

         (d) At least 10 days before it takes any action contemplated by Section
4(b) or 4(c), such Lien Grantor will ensure that (i) all financing statements
and amendments or supplements thereto, continuation statements and other
documents required to be filed or recorded in order to perfect and protect the
Transaction Liens against all creditors of and purchasers from such Lien Grantor
after it takes such action (except any applicable continuation statements that
are to be filed more than six months after the date thereof) have been filed or
recorded in each office necessary for such purpose, (ii) all fees and taxes, if
any, payable in connection with such filings or recordations have been paid in
full and (iii) except as otherwise agreed by the Administrative Agent, such
action will not adversely affect the perfection or priority of the Transaction
Lien on any Collateral to be owned by such Lien Grantor after it takes such
action or the accuracy of such Lien Grantor's representations and warranties
herein relating to such Collateral.

         (e) Such Lien Grantor will not sell, lease, exchange, assign or
otherwise dispose of, or grant any option with respect to, any of its Collateral
except as permitted pursuant to the terms of the Credit Agreement.

         SECTION 5. Accounts. Each Lien Grantor represents, warrants and
covenants as follows:

         (a) Such Lien Grantor will use commercially reasonable efforts to cause
to be collected from its account debtors, when due, all amounts owing under its
Accounts (including delinquent Accounts, which will be collected in accordance
with lawful collection procedures) and will apply all amounts collected thereon,
forthwith upon receipt thereof, to the outstanding balances of such Accounts.
Subject to the rights of the Administrative Agent and the other Secured Parties
hereunder if an Event of Default shall have occurred and be continuing, such
Lien Grantor may allow in the ordinary course of business as adjustments to
amounts owing under its Accounts (i) any extension or renewal of the time or
times for payment, or settlement for less than the total unpaid balance, that
such Lien Grantor finds appropriate in accordance with sound business judgment
and (ii) refunds or credits, all in the ordinary course of business and
consistent with such Lien Grantor's customary collection practices. The costs
and expenses (including attorney's fees) of collection, whether incurred by such
Lien Grantor or the Administrative Agent, shall be paid by such Lien Grantor.


                                       18
<PAGE>


         (b) If payments with respect to any of such Lien Grantor's Accounts are
received in a lockbox or similar account, such Lien Grantor will, at all times
from a date not later than 30 days (or such longer period, not exceeding 75
days, as the Administrative Agent may approve, such approval not to be
unreasonably withheld) after the Initial Collateral Date, (i) cause such Account
to be a Controlled Deposit Account and (ii) cause the relevant Depositary Bank
to subordinate to the relevant Transaction Lien all its claims to such account
(except its right to deduct its normal operating charges and any uncollected
funds previously credited thereto). The Administrative Agent will instruct the
relevant Depositary Bank to transfer funds credited to any such Account, as
promptly as practicable after receipt thereof, to a concentration account which
is a Controlled Deposit Account designated by such Lien Grantor; provided that,
if an Event of Default shall have occurred and be continuing, the Administrative
Agent may designate the Controlled Deposit Account to which such funds are
transferred.

         (c) If an Event of Default shall have occurred and be continuing, such
Lien Grantor will, if requested to do so by the Administrative Agent, promptly
notify (and such Lien Grantor authorizes the Administrative Agent so to notify)
each account debtor in respect of any of its Accounts that such Accounts have
been assigned to the Administrative Agent hereunder, and that any payments due
or to become due in respect of such Accounts are to be made directly to the
Administrative Agent or its designee.

         SECTION 6. Recordable Intellectual Property. On the Initial Collateral
Date (in the case of an Original Lien Grantor) or the date on which it signs and
delivers its first Security Agreement Supplement (in the case of any other Lien
Grantor), such Lien Grantor will sign and deliver to the Administrative Agent
Intellectual Property Security Agreements with respect to all Recordable
Intellectual Property then owned by it. From time to time thereafter, whenever
any Lien Grantor acquires any Recordable Intellectual Property or determines
that any Intellectual Property owned by it has become Recordable Intellectual
Property, it will promptly notify the Administrative Agent thereof and make all
Intellectual Property Filings necessary to record the Transaction Liens on such
Recordable Intellectual Property.

         SECTION 7. Investment Property. Each Lien Grantor represents, warrants
and covenants as follows:

         (a) Security Entitlements. Within 30 days (or such longer period, not
exceeding 75 days, as the Administrative Agent may approve, such approval not to
be unreasonably withheld) after the date this Agreement becomes effective as to
such Lien Grantor, such Lien Grantor will, with respect to each Security
Entitlement then owned by it, enter into (and use reasonable commercial efforts
to cause the relevant Securities Intermediary to enter into) a Securities
Account


                                       19
<PAGE>


Control Agreement in respect of such Security Entitlement and the Securities
Account to which the underlying Financial Asset is credited and will deliver
such Securities Account Control Agreement to the Administrative Agent (which
shall enter into the same). Thereafter, whenever such Lien Grantor acquires any
other Security Entitlement, such Lien Grantor will, as promptly as practicable,
cause the underlying Financial Asset to be credited to a Controlled Securities
Account. The provisions of this subsection are subject to Sections 8(b). With
respect to any Controlled Securities Account in which Merrill Lynch, Pierce,
Fenner & Smith Incorporated is the Securities Intermediary, such Lien Grantor
will not acquire any of the following assets: shares of ML Ready Assets Trust,
USA Government and USA Treasury money market funds, non-listed limited
partnership interests, annuities and life insurance contracts, and precious
metals.

         (b) Perfection as to Security Entitlements. So long as the Financial
Asset underlying any Security Entitlement owned by such Lien Grantor is credited
to a Controlled Securities Account, (i) the Transaction Lien on such Security
Entitlement will be perfected, subject to no prior Liens or rights of others
(except Liens and rights of the relevant Securities Intermediary that are
Permitted Liens) and (ii) the Administrative Agent will have Control of such
Security Entitlement.

         (c) Agreement as to Applicable Jurisdiction. In respect of all Security
Entitlements owned by such Lien Grantor, and all Securities Accounts to which
the related Financial Assets are credited, the Securities Intermediary's
jurisdiction (determined as provided in UCC Section 8-110(e)) will at all times
be located in the United States.

         SECTION 8. Controlled Deposit Accounts. Each Lien Grantor represents,
warrants and covenants as follows:

         (a) At all times 30 days (or such longer period, not exceeding 75 days,
as the Administrative Agent may approve, such approval not to be unreasonably
withheld) or more after the Initial Collateral Date, all cash owned by such Lien
Grantor (other than cash to be deposited in a Payroll Account) will be
deposited, upon or promptly after the receipt thereof, in one or more Controlled
Deposit Accounts; provided that (i) cash subject to a Permitted Lien securing
obligations other than Secured Obligations, (ii) cash on deposit in a Payroll
Account and (iii) other cash balances aggregating not in excess of $1,000,000
may be maintained in Deposit Accounts which are not Controlled Deposit Accounts.
Each Controlled Deposit Account will be operated as provided in Section 10.

         (b) In respect of each Controlled Deposit Account, the Depositary
Bank's jurisdiction (determined as provided in Revised UCC Section 9-304) will
at all times after the UCC Revision Date be a jurisdiction in which Revised
Article 9 is in effect.


                                       20
<PAGE>


         (c) On and after the applicable UCC Revision Date, so long as the
Administrative Agent has Control of a Controlled Deposit Account, the
Transaction Lien on such Controlled Deposit Account will be perfected, subject
to no prior Liens or rights of others (except the Depositary Bank's right to
deduct its normal operating charges and any uncollected funds previously
credited thereto) except Liens arising under Permitted Specified Security
Hedging Transactions.

         SECTION 9. Cash Collateral Accounts. (a) At any time while an Event of
Default has occurred and is continuing, the Administrative Agent will establish
with respect to each Lien Grantor an account (its "Cash Collateral Account"), in
the name and under the exclusive control of the Administrative Agent, into which
all amounts owned by such Lien Grantor that are required to be deposited therein
upon the occurrence and during the continuance of an Event of Default pursuant
to Section 2.05(j) of the Credit Agreement or any other provision of the Loan
Documents (including Section 9(b)) shall be deposited from time to time. No Lien
Grantor shall be required to (but any Lien Grantor may, at its option) deposit
any amounts owed by it into its Cash Collateral Account unless an Event of
Default has occurred and is continuing. Each Cash Collateral Account will be
operated as provided in this Section and Section 10.

         (b) Upon the occurrence and during the continuance of an Event of
Default, the Administrative Agent shall deposit in the Cash Collateral Account
of each Lien Grantor:

                  (i) each Cash Distribution required by the provisions of the
         Loan Documents to be deposited therein; and

                  (ii) each amount realized or otherwise received by the
         Administrative Agent with respect to assets of such Lien Grantor upon
         any exercise of remedies pursuant to any Collateral Document.

         (c) At any time while no Event of Default has occurred and is
continuing, upon request by the relevant Lien Grantor, the Administrative Agent
shall withdraw any amounts on deposit in the Cash Collateral Accounts and return
such amount to such Lien Grantor.

         SECTION 10. Operation of Collateral Accounts. (a) All Cash
Distributions received with respect to assets held in any Collateral Account
shall be deposited therein promptly upon receipt thereof.

         (b) Cash held in any Controlled Securities Account may, until
withdrawn, be invested and reinvested in such Investments as the relevant Lien
Grantor shall


                                       21
<PAGE>


request from time to time; provided that, if an Event of Default shall have
occurred and be continuing, Administrative Agent may select such Investments.

         (c) Cash held in any Controlled Deposit Account or Cash Collateral
Account may, until withdrawn, be invested and reinvested in such Investments as
the relevant Lien Grantor shall request from time to time; provided that (i) if
an Event of Default shall have occurred and be continuing, the Administrative
Agent may select such Cash Equivalent Investments and (ii) if such Cash
Equivalent Investments are to be held in a Securities Account, either (x) the
Administrative Agent is the Entitlement Holder with respect to such Cash
Equivalent Investments or (y) the relevant Entitlement Holder and the relevant
Securities Intermediary shall have theretofore entered into a Securities Account
Control Agreement with respect to such Securities Account and delivered it to
the Administrative Agent (which shall enter into the same).

         (d) With respect to each Collateral Account (except a Cash Collateral
Account, as to which Section 9 applies), the Administrative Agent will instruct
the relevant Securities Intermediary or Depositary Bank that the relevant Lien
Grantor may withdraw, or direct the disposition of, funds held therein unless
and until the Administrative Agent rescinds such instruction. The Administrative
Agent will not rescind such instructions unless directed to do so by the
Required Lenders at a time when an Event of Default shall have occurred and be
continuing.

         (e) No Lien Grantor will cause funds to be transferred from a
Collateral Account to any other account owned by a Lien Grantor unless (i) such
other account is a Collateral Account or (ii) subject to the rights of the
Secured Parties upon the occurrence and during the continuance of an Event of
Default, such funds constitute a payment that is not prohibited by the Credit
Agreement; provided that, subject to subsection (d) above, a Lien Grantor may
transfer funds from any Collateral Account (except a Cash Collateral Account) to
any account of a Lien Grantor that is not a Collateral Account unless,
immediately after such transfer, the aggregate amount held in all such accounts
that are not Collateral Accounts (other than Payroll Accounts) would exceed
$1,000,000.

         (f) If an Event of Default shall have occurred and be continuing, the
Administrative Agent may (i) retain, or instruct the relevant Securities
Intermediary or Depositary Bank to retain, all cash and investments then held in
any Collateral Account, (ii) liquidate, or instruct the relevant Securities
Intermediary or Depositary Bank to liquidate, any or all investments held
therein and/or (iii) withdraw any amounts held therein and apply such amounts as
provided in Section 12.

         (g) If immediately available cash on deposit in any Collateral Account
is not sufficient to make any distribution or withdrawal to be made pursuant
hereto,


                                       22
<PAGE>


the Administrative Agent will cause to be liquidated, as promptly as
practicable, such investments held in or credited to such Collateral Account as
shall be required to obtain sufficient cash to make such distribution or
withdrawal and, notwithstanding any other provision hereof, such distribution or
withdrawal shall not be made until such liquidation has taken place.

         (h) Each Lien Grantor will maintain its lockbox accounts and general
operating account with a Secured Party.

         SECTION 11. Remedies upon Event of Default. (a) If an Event of Default
shall have occurred and be continuing, the Administrative Agent may exercise (or
cause its sub-agents to exercise) any or all of the remedies available to it (or
to such sub-agents) under the Collateral Documents.

         (b) Without limiting the generality of the foregoing, if an Event of
Default shall have occurred and be continuing, the Administrative Agent may
exercise on behalf of the Secured Parties all the rights of a secured party
under the UCC (whether or not in effect in the jurisdiction where such rights
are exercised) with respect to any Collateral and, in addition, the
Administrative Agent may, without being required to give any notice, except as
herein provided or as may be required by mandatory provisions of law, withdraw
all cash held in the Collateral Accounts and apply such cash as provided in
Section 12 and, if there shall be no such cash or if such cash shall be
insufficient to pay all the Secured Obligations in full, sell, lease, license or
otherwise dispose of the Collateral or any part thereof. Notice of any such sale
or other disposition shall be given to the relevant Lien Grantor(s) as required
by Section 14. Each Secured Party acknowledges and agrees that (i) any
disposition of Collateral consisting of securities that have not been registered
under the Securities Act shall be subject to compliance therewith and (ii) the
exercise of any rights or remedies with respect to any Collateral consisting of
a contract or license or sublicense shall be subject to the provisions thereof
(including any provisions regarding assignability or confidentiality, to the
extent such provisions are not void or unenforceable).

         (c) Without limiting the generality of the foregoing, if an Event of
Default shall have occurred and be continuing:

                  (i) the Administrative Agent may license or sublicense,
         whether general, special or otherwise, and whether on an exclusive or
         non-exclusive basis, any Pledged Intellectual Property throughout the
         world for such term or terms, on such conditions and in such manner as
         the Administrative Agent shall reasonably determine; provided that such
         licenses or sublicenses do not conflict with any existing license or
         sublicense;


                                       23
<PAGE>


                 (ii) the Administrative Agent may (without assuming any
         obligation or liability thereunder), at any time and from time to time,
         in its sole and reasonable discretion, enforce (and shall have the
         exclusive right to enforce) against any licensee or sublicensee all
         rights and remedies of any Lien Grantor in, to and under any of its
         Pledged Intellectual Property and take or refrain from taking any
         action under any thereof, and each Lien Grantor releases the
         Administrative Agent and each other Secured Party from liability for,
         and agrees to hold the Administrative Agent and each other Secured
         Party free and harmless from and against any claims and expenses
         arising out of, any lawful action so taken or omitted to be taken with
         respect thereto, except for claims and expenses arising from the
         Administrative Agent's or such Secured Party's gross negligence or
         willful misconduct; and

                (iii) upon request by the Administrative Agent (which shall
         not be construed as implying any limitation on its rights or powers),
         each Lien Grantor will execute and deliver to the Administrative Agent
         a power of attorney, in form and substance reasonably satisfactory to
         the Administrative Agent, for the implementation of any sale, lease,
         license or other disposition of any of such Lien Grantor's Pledged
         Intellectual Property or any action related thereto. In connection with
         any such disposition, but subject to any confidentiality restrictions
         imposed on such Lien Grantor in any license or similar agreement or
         with respect to any customer information, such Lien Grantor will supply
         to the Administrative Agent its know-how and expertise relating to the
         relevant Intellectual Property or the products or services made or
         rendered in connection with such Intellectual Property, and its
         customer lists and other records relating to such Intellectual Property
         and to the distribution of said products or services.

         SECTION 12. Application of Proceeds. (a) If an Event of Default shall
have occurred and be continuing, the Administrative Agent may apply (i) any cash
held in the Collateral Accounts and (ii) the proceeds of any sale or other
disposition of all or any part of the Collateral, in the following order of
priorities:

                  first, to pay the reasonable expenses of such sale or other
         disposition, including reasonable compensation to agents of and counsel
         for the Administrative Agent, and all expenses, liabilities and
         advances incurred or made by the Administrative Agent in connection
         with the Collateral Documents, and any other amounts then due and
         payable to the Administrative Agent pursuant to Section 13 or to the
         Administrative Agent pursuant to Section 10.03 of the Credit Agreement;


                                       24
<PAGE>


                  second, to pay the unpaid principal of the Secured Obligations
         ratably (or provide for the payment thereof pursuant to Section 12(b)),
         until payment in full of the principal of all Secured Obligations shall
         have been made (or so provided for);

                  third, to pay ratably all interest (including Post-Petition
         Interest) on the Secured Obligations and all facility and other fees
         payable under the Credit Agreement, until payment in full of all such
         interest and fees shall have been made;

                  fourth, to pay all other Secured Obligations ratably (or
         provide for the payment thereof pursuant to Section 12(b)), until
         payment in full of all such other Secured Obligations shall have been
         made (or so provided for); and

                  finally, to pay to the relevant Lien Grantor, or as a court of
         competent jurisdiction may direct, any surplus then remaining from the
         proceeds of the Collateral owned by it;

provided that (i) any Collateral owned by a Subsidiary Loan Party and any
Proceeds thereof shall be applied pursuant to the foregoing clauses first,
second, third and fourth only to the extent permitted by any limitations in such
Subsidiary Loan Party's Subsidiary Guarantee and (ii) with respect to any asset
constituting "Collateral" and subject to a Lien permitted under clauses (iv),
(v), (viii) and (x) of Section 6.02(a) of the Credit Agreement, which Lien
attached and was perfected prior to the time such asset became "Collateral",
such Collateral and any Proceeds thereof shall be applied, to the extent
required by the agreements governing such Lien, to repay the Indebtedness
secured by such Lien, prior to any application thereof in accordance with this
subsection (a). The Administrative Agent may make such distributions hereunder
in cash or in kind or, on a ratable basis, in any combination thereof.

         (b) If at any time any portion of any monies collected or received by
the Administrative Agent would, but for the provisions of this Section 12(b), be
payable pursuant to Section 12(a) in respect of a Contingent Secured Obligation,
the Administrative Agent shall not apply any monies to pay such Contingent
Secured Obligation but instead shall request the holder thereof, at least 10
days before each proposed distribution hereunder, to notify the Administrative
Agent as to the maximum amount of such Contingent Secured Obligation if then
ascertainable (e.g., in the case of a letter of credit, the maximum amount
available for subsequent drawings thereunder). If the holder of such Contingent
Secured Obligation does not notify the Administrative Agent of the maximum
ascertainable amount thereof at least two Business Days before such
distribution, such holder will not be entitled to share in such distribution. If
such holder does so notify the Administrative Agent as to the maximum
ascertainable amount thereof, the


                                       25
<PAGE>


Administrative Agent will allocate to such holder a portion of the monies to be
distributed in such distribution, calculated as if such Contingent Secured
Obligation were outstanding in such maximum ascertainable amount. However, the
Administrative Agent will not apply such portion of such monies to pay such
Contingent Secured Obligation, but instead will hold such monies or invest such
monies in Cash Equivalent Investments. All such monies and Cash Equivalent
Investments and all proceeds thereof will constitute Collateral hereunder, but
will be subject to distribution in accordance with this Section 12(b) rather
than Section 12(a). The Administrative Agent will hold all such monies and Cash
Equivalent Investments and the net proceeds thereof in trust until all or part
of such Contingent Secured Obligation becomes a Non-Contingent Secured
Obligation, whereupon the Administrative Agent at the request of the relevant
Secured Party will apply the amount so held in trust to pay such Non-Contingent
Secured Obligation; provided that, if the other Secured Obligations theretofore
paid pursuant to the same clause of Section 12(a) (i.e., clause second or
fourth) were not paid in full, the Administrative Agent will apply the amount so
held in trust to pay the same percentage of such Non-Contingent Secured
Obligation as the percentage of such other Secured Obligations theretofore paid
pursuant to the same clause of Section 12(a). If (i) the holder of such
Contingent Secured Obligation shall advise the Administrative Agent that no
portion thereof remains in the category of a Contingent Secured Obligation and
(ii) the Administrative Agent still holds any amount held in trust pursuant to
this Section 12(b) in respect of such Contingent Secured Obligation (after
paying all amounts payable pursuant to the preceding sentence with respect to
any portions thereof that became Non-Contingent Secured Obligations), such
remaining amount will be applied by the Administrative Agent in the order of
priorities set forth in Section 12(a).

         (c) In making the payments and allocations required by this Section,
the Administrative Agent may rely upon information supplied to it pursuant to
Section 16(e). All distributions made by the Administrative Agent pursuant to
this Section shall be final (except in the event of manifest error) and the
Administrative Agent shall have no duty to inquire as to the application by any
Secured Party of any amount distributed to it.

         SECTION 13. Fees and Expenses; Indemnification. (a) The Borrower will
forthwith pay to the Administrative Agent, within 30 days of written demand
therefor:

                  (i) the amount of any taxes that the Administrative Agent may
         have been required to pay by reason of the Transaction Liens or to free
         any Collateral from any other Lien thereon (other than Permitted
         Liens);

                 (ii) the amount of any and all reasonable out-of-pocket
         expenses, including transfer taxes and reasonable fees and expenses of
         counsel and


                                       26
<PAGE>


         other experts, that the Administrative Agent may incur in connection
         with (x) the administration or enforcement of the Collateral Documents,
         including such expenses as are incurred to preserve the value of the
         Collateral or the validity, perfection, rank or value of any
         Transaction Lien, (y) the collection, sale or other disposition of any
         Collateral or (z) the exercise by the Administrative Agent of any of
         its rights or powers under the Collateral Documents;

                (iii) the amount of any fees that the Borrower shall have
         agreed in writing to pay to the Administrative Agent and that shall
         have become due and payable in accordance with such written agreement;
         and

                 (iv) the amount required to indemnify the Administrative Agent
         for, or hold it harmless and defend it against, any loss, liability or
         expense (including the reasonable fees and expenses of its counsel and
         any experts or sub-agents appointed by it hereunder) incurred or
         suffered by the Administrative Agent in connection with the Collateral
         Documents, except to the extent that such loss, liability or expense
         arises from the Administrative Agent's gross negligence or willful
         misconduct or a breach of any duty that the Administrative Agent has
         under this Agreement (after giving effect to Sections 15 and 16).

Any such amount not paid to the Administrative Agent within said 30 day period
will bear interest for each day thereafter until paid at a rate per annum equal
to the sum of 2% plus the rate applicable to ABR Loans for such day.

         (b) If any transfer tax, documentary stamp tax or other tax is payable
in connection with any transfer or other transaction provided for in the
Collateral Documents, the Borrower will pay such tax and provide any required
tax stamps to the Administrative Agent or as otherwise required by law.

         (c) The Borrower shall indemnify each of the Secured Parties, their
respective affiliates and the respective directors, officers, agents and
employees of the foregoing (each an "Indemnitee") against, and hold each
Indemnitee harmless from, any and all liabilities, losses, damages, costs and
expenses of any kind (including reasonable expenses of investigation by
engineers, environmental consultants and similar technical personnel and
reasonable fees and disbursements of counsel) arising out of, or in connection
with any and all Environmental Liabilities. Without limiting the generality of
the foregoing, each Lien Grantor waives all rights for contribution and all
other rights of recovery with respect to liabilities, losses, damages, costs and
expenses arising under or related to Environmental Laws that it might have by
statute or otherwise against any Indemnitee, except to the extent such
Environmental Liabilities are directly attributable to such Indemnitee.


                                       27
<PAGE>


         SECTION 14. Authority to Administer Collateral. Each Lien Grantor
irrevocably appoints the Administrative Agent its true and lawful attorney, with
full power of substitution, in the name of such Lien Grantor, any Secured Party
or otherwise, for the sole use and benefit of the Secured Parties, but at the
Borrower's expense, to the extent permitted by law to exercise, at any time and
from time to time while an Event of Default shall have occurred and be
continuing, all or any of the following powers with respect to all or any of
such Lien Grantor's Collateral:

                  (a) to demand, sue for, collect, receive and give acquittance
         for any and all monies due or to become due upon or by virtue thereof,

                  (b) to settle, compromise, compound, prosecute or defend any
         action or proceeding with respect thereto,

                  (c) to sell, lease, license or otherwise dispose of the same
         or the proceeds or avails thereof, as fully and effectually as if the
         Administrative Agent were the absolute owner thereof, and

                  (d) to extend the time of payment of any or all thereof and to
         make any allowance or other adjustment with reference thereto;

provided that, except in the case of Collateral that is perishable or threatens
to decline speedily in value or is of a type customarily sold on a recognized
market, the Administrative Agent will give the relevant Lien Grantor at least
ten days' prior written notice of the time and place of any public sale thereof
or the time after which any private sale or other intended disposition thereof
will be made. The Administrative Agent and each Lien Grantor agree that such
notice constitutes "reasonable notification" within the meaning of Current UCC
Section 9-504(3). If any such notice is given after the UCC Revision Date, it
shall (i) contain the information specified in Revised UCC Section 9-613, (ii)
be Authenticated and (iii) be sent to the parties required to be notified
pursuant to Revised UCC Section 9-611(c); provided that, if the Administrative
Agent fails to comply with this sentence in any respect, its liability for such
failure shall be limited to the liability (if any) imposed on it as a matter of
law under the UCC.

         SECTION 15. Limitation on Duty in Respect of Collateral. Beyond the
exercise of reasonable care in the custody and preservation thereof, the
Administrative Agent will have no duty as to any Collateral in its possession or
control or in the possession or control of any sub-agent or bailee or any income
therefrom or as to the preservation of rights against prior parties or any other
rights pertaining thereto. The Administrative Agent will be deemed to have
exercised reasonable care in the custody and preservation of the Collateral in
its possession or control if such Collateral is accorded treatment substantially
equal to that which


                                       28
<PAGE>


it accords its own property, and will not be liable or responsible for any loss
or damage to any Collateral, or for any diminution in the value thereof, by
reason of any act or omission of any sub-agent or bailee selected by the
Administrative Agent in good faith or by reason of any act or omission by the
Administrative Agent pursuant to instructions from the Administrative Agent,
except to the extent that such liability arises from the Administrative Agent's
gross negligence or willful misconduct.

         SECTION 16. General Provisions Concerning the Administrative Agent. (a)
Authority. The Administrative Agent is authorized to take such actions and to
exercise such powers as are delegated to the Administrative Agent by the terms
of the Collateral Documents and the Loan Documents, together with such actions
and powers as are reasonably incidental thereto.

         (b) Rights and Powers as a Secured Party. The institution serving as
the Administrative Agent shall, in its capacity as a Secured Party, have the
same rights and powers as any other Secured Party and may exercise the same as
though it were not the Administrative Agent.

         (c) Authority to Rely on Certain Writings, Statements and Advice. The
Administrative Agent shall be entitled to rely on, and shall not incur any
liability for relying on, any notice, request, certificate, consent, statement,
instrument, document or other writing believed by it to be genuine and to have
been signed or sent by the proper Person. The Administrative Agent also may rely
on any statement made to it orally or by telephone and believed by it to be made
by the proper Person, and shall not incur any liability for relying thereon. The
Administrative Agent may consult with legal counsel (who may be counsel for the
Borrower), independent accountants and other experts selected by it, and shall
not be liable for any action taken or not taken by it in accordance with the
advice of any such counsel, accountant or expert.

         (d) Sub-Agents and Related Parties. The Administrative Agent may
perform any of its duties and exercise any of its rights and powers through one
or more sub-agents appointed by it. The Administrative Agent and any such sub-
agent may perform any of its duties and exercise any of its rights and powers
through its Affiliates or its or their respective directors, officers,
employees, agents and advisors. The exculpatory provisions of Section 15 and
this Section shall apply to any such sub-agent and to the Related Parties of the
Administrative Agent and any such sub-agent.

         (e) Information as to Secured Obligations and Actions by Secured
Parties. For all purposes of the Collateral Documents, including determining the
amounts of the Secured Obligations and whether a Secured Obligation is a
Contingent Secured Obligation or not, or whether any action has been taken under
any Secured


                                       29
<PAGE>


Agreement, the Administrative Agent will be entitled to rely on information from
(i) any Secured Party for information as to its Secured Obligations and actions
taken by it, to the extent that the Administrative Agent has not obtained such
information from the foregoing sources, and (ii) the Borrower, to the extent
that the Administrative Agent has not obtained information from the foregoing
sources.

         (f) The Administrative Agent may refuse to act on any notice, consent,
direction or instruction from the Administrative Agent or any Secured Parties or
any agent, trustee or similar representative thereof that, in the Administrative
Agent's opinion, (i) is contrary to law or the provisions of any Collateral
Document, (ii) may expose the Administrative Agent to liability (unless the
Administrative Agent shall have been indemnified, to its reasonable
satisfaction, for such liability by the Secured Parties that gave, or instructed
the Administrative Agent to give, such notice, consent, direction or
instruction) or (iii) is unduly prejudicial to Secured Parties not joining in
such notice, consent, direction or instruction.

         SECTION 17. Termination of Transaction Liens; Release of Collateral.
(a) The Transaction Liens granted by each Lien Grantor shall terminate when all
the Release Conditions are satisfied.

         (b) The Transaction Liens granted by the relevant Lien Grantor (w) with
respect to any Specified Security shall automatically terminate upon such Lien
Grantor entering into any Permitted Specified Security Hedging Transaction
pursuant to which such Lien Grantor shall be required to deliver such Specified
Security to the counterparty to such Permitted Specified Security Hedging
Transaction, (x) with respect to any Pledged Receivables shall automatically
terminate when such Receivables have become Transferred Receivables, (y) with
respect to any Collateral shall automatically terminate when such Collateral
becomes ADP Property and subject to the Operative Documents, and (z) with
respect to any other Collateral (including, without limitation, any Equity
Interests in the Borrower's Williams Communications Solutions business unit or
ATL or any Subsidiary Loan Party), shall automatically terminate upon the sale,
transfer, lease or other disposition of such Collateral permitted by and
consummated in accordance with Section 6.05 of the Credit Agreement to a Person
other than the Borrower, Holdings or one of its Subsidiaries (each, a "Permitted
Collateral Sale"), so long as no Default shall have occurred and then be
continuing. Such termination shall not require the consent of any Secured Party,
and the Administrative Agent and any third party shall be fully protected in
relying on a certificate of the Borrower as conclusive proof that (i) any
particular sale of assets is a Permitted Collateral Sale, (ii) any Pledged
Receivables qualify as Transferred Receivables, (iii) any Collateral has become
ADP Property, (iv) any Pledged Equity Interest constitutes a Specified Security
subject to a Permitted Specified Hedging Transaction and (v) no Default shall
have occurred and then be continuing.


                                       30
<PAGE>


         (c) In the case of any Pledged Receivables, the Transaction Liens
granted by the relevant Lien Grantor with respect to the Related Transferred
Rights shall automatically terminate when such Pledged Receivables become
Transferred Receivables, so long as no Default has occurred and is then
continuing. Such termination shall not require the consent of any Secured Party,
and the Administrative Agent shall be fully protected in relying on a
certificate of the Borrower stating that any Pledged Receivables qualify as
Transferred Receivables, the Administrative Agent and any third party shall be
fully protected in relying on such certificate as conclusive proof that (i) the
Related Transferred Rights are not Collateral and (ii) no Default shall have
occurred and then be continuing.

         (d) For avoidance of doubt, the operation of subsections (b) and (c) in
the event of a transfer of Pledged Receivables from a Lien Grantor to the
Borrower is as follows: The Transaction Liens granted by the Lien Grantor in
such Pledged Receivables and the related rights and interests in such Collateral
terminate upon such transfer. However, the Borrower simultaneously acquires
rights in such Collateral, and the Transaction Liens granted by the Borrower
shall simultaneously attach thereto. The parties intend that any such
transaction shall be a contemporaneous exchange for new value given to the
Borrower.

         (e) At any time before the Transaction Liens terminate, the
Administrative Agent may, at the written request of the Borrower, release any
Collateral with the prior written consent of the Required Lenders (or, solely if
such Collateral constitutes all or substantially all of the "Collateral" under
all of the Collateral Documents then in effect, all of the Lenders).

         (f) Upon any termination of a Transaction Lien or release of Collateral
as described in the foregoing subsection, the Administrative Agent will, at the
expense of the relevant Lien Grantor, promptly execute and deliver to such Lien
Grantor such documents as such Lien Grantor shall reasonably request (including
without limitation UCC-3 termination statements) to evidence the termination of
such Transaction Lien or the release of such Collateral, as the case may be,
and, if such Collateral consists of Equity Interests, deliver to the relevant
Lien Grantor all the stock certificates evidencing such Collateral then in the
possession of the Administrative Agent.

         SECTION 18. Additional Secured Obligations. The Borrower may from time
to time designate its obligations or the obligations of any Subsidiary Loan
Party under any Hedging Agreement with any Lender or any affiliate of any Lender
as an additional Secured Obligation for purposes hereof by delivering to the
Administrative Agent a certificate signed by a Financial Officer that (i)
identifies such Hedging Agreement, specifying the name and address of the other
party thereto, the notional principal amount thereof and the expiration date
thereof


                                       31
<PAGE>


and (ii) states that the Borrower's or the Subsidiary Loan Party's obligations
thereunder are designated as Secured Obligations for purposes hereof.

         SECTION 19. Notices. Each notice, request or other communication given
to any party hereunder shall be in writing (which term includes facsimile or
other electronic transmission) and shall be effective (i) when delivered to such
party at its address specified below, (ii) when sent to such party by facsimile
or other electronic transmission, addressed to it at its facsimile number or
electronic address specified below, and such party sends back an electronic
confirmation of receipt or (iii) ten days after being sent to such party by
certified or registered United States mail, addressed to it at its address
specified below, with first class or airmail postage prepaid:

         (a) in the case of any Original Lien Grantor:

                Attn: General Counsel
                Williams Communications
                One Williams Center
                Tulsa, OK 74172
                Tel: 918-573-5057
                Fax: 918-573-3005
                Email: david.newsome@wcg.com

         (b) in the case of any other Lien Grantor, its address, facsimile
     number or e-mail address set forth in its first Security Agreement
     Supplement; or

         (c) in the case of the Administrative Agent:

                Attn: Yamile Angulo, Senior Risk Control Specialist
                Bank of America, N.A.
                901 Main Street, 14th floor
                Dallas, TX  75202-3714
                Tel: 214-209-1229
                Fax: 214-209-0944
                Email: yamile.d.angulo@bankofamerica.com

Any party may change its address, facsimile number and/or e-mail address for
purposes of this Section by giving notice of such change to the Administrative
Agent and the Lien Grantors in the manner specified above.


                                       32
<PAGE>


         SECTION 20. No Implied Waivers; Remedies Not Exclusive. No failure by
the Administrative Agent or any Secured Party to exercise, and no delay in
exercising and no course of dealing with respect to, any right or remedy under
any Collateral Document shall operate as a waiver thereof; nor shall any single
or partial exercise by the Administrative Agent or any Secured Party of any
right or remedy under any Loan Document preclude any other or further exercise
thereof or the exercise of any other right or remedy. The rights and remedies
specified in the Loan Documents are cumulative and are not exclusive of any
other rights or remedies provided by law.

         SECTION 21. Successors and Assigns. This Agreement is for the benefit
of the Administrative Agent and the Secured Parties. If all or any part of any
Secured Party's interest in any Secured Obligation is assigned or otherwise
transferred, the transferor's rights hereunder, to the extent applicable to the
obligation so transferred, shall be automatically transferred with such
obligation. This Agreement shall be binding on the Lien Grantors and their
respective successors and assigns, except that the Lien Grantors may not assign
or otherwise transfer any of their rights or obligations hereunder without the
prior written consent of each Lender.

         SECTION 22. Amendments and Waivers. Neither this Agreement nor any
provision hereof may be waived, amended, modified or terminated except pursuant
to an agreement or agreements in writing entered into by the parties hereto,
with the consent of the Required Lenders (or, solely if waiver, amendment,
modification or termination (other than a termination effected by operation of
Section 17(a), 17(b) or 17(c)) constitutes a release of all or substantially all
of the "Collateral" under all of the Collateral Documents then in effect, all of
the Lenders).

         SECTION 23. Choice of Law. This Agreement shall be construed in
accordance with and governed by the laws of the State of New York, except as
otherwise required by mandatory provisions of law and except to the extent that
remedies provided by the laws of any jurisdiction other than the State of New
York are governed by the laws of such jurisdiction.

         SECTION 24. Waiver of Jury Trial. EACH PARTY HERETO WAIVES, TO THE
FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A TRIAL BY
JURY IN ANY LEGAL PROCEEDING DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING
TO ANY COLLATERAL DOCUMENT OR ANY TRANSACTION CONTEMPLATED THEREBY (WHETHER
BASED ON CONTRACT, TORT OR ANY OTHER THEORY). EACH PARTY HERETO (A) CERTIFIES
THAT NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED,
EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF
LITIGATION, SEEK TO


                                       33
<PAGE>


ENFORCE THE FOREGOING WAIVER AND (B) ACKNOWLEDGES THAT IT AND THE OTHER PARTIES
HERETO HAVE BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS,
THE MUTUAL WAIVERS AND CERTIFICATIONS IN THIS SECTION.

         SECTION 25. Severability. If any provision of any Collateral Document
is invalid or unenforceable in any jurisdiction, then, to the fullest extent
permitted by law, (i) the other provisions of the Collateral Documents shall
remain in full force and effect in such jurisdiction and shall be liberally
construed in favor of the Administrative Agent and the Secured Parties in order
to carry out the intentions of the parties thereto as nearly as may be possible
and (ii) the invalidity or unenforceability of such provision in such
jurisdiction shall not affect the validity or enforceability thereof in any
other jurisdiction.

         SECTION 26. Additional Lien Grantors. Any Restricted Subsidiary may
become a party hereto by signing and delivering to the Administrative Agent a
Security Agreement Supplement, whereupon such Subsidiary shall become a "Lien
Grantor" as defined herein.

         SECTION 27. Effectiveness. This Agreement shall become effective on and
as of the time and date when the conditions set forth in the Section 5.11A of
the Credit Agreement are met. For the avoidance of doubt, this Agreement shall
become effective on the date hereof, but not until the time at which the Parent
ceases to own at least a majority of the outstanding securities having ordinary
voting power of Holdings.


                                       34
<PAGE>


         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their respective authorized officers as of the day and year
first above written.

                                    WILLIAMS COMMUNICATIONS, LLC

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS COMMUNICATIONS GROUP,
                                       INC.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    BANK OF AMERICA, N.A., as
                                       Administrative Agent

                                    By /s/ Pamela S. Kurtzman
                                       -----------------------------------------
                                       Title: Principal

                                    CRITICAL CONNECTIONS, INC.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WCS COMMUNICATIONS SYSTEMS, INC.


                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer


                                       35
<PAGE>



                                    WCS, INC.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS COMMUNICATIONS OF
                                       VIRGINIA, INC.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS COMMUNICATIONS
                                       PROCUREMENT, L.L.C.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS COMMUNICATIONS
                                       PROCUREMENT, LP

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS GLOBAL COMMUNICATIONS
                                       HOLDINGS, INC.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer




                                       36
<PAGE>


                                    WILLIAMS INTERNATIONAL
                                       VENTURES COMPANY

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS LEARNING NETWORK, INC.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS LOCAL NETWORK, INC.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS TECHNOLOGY CENTER, LLC
                                       By:  Williams Communications, LLC As
                                            Sole Member.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer

                                    WILLIAMS COMMUNICATIONS
                                       AIRCRAFT, LLC
                                       By:  Williams Communications, LLC As
                                            Sole Member.

                                    By /s/ Howard S. Kalika
                                       -----------------------------------------
                                       Title: Vice President and Treasurer




                                       37