Exhibit 4.3

                             STOCKHOLDERS AGREEMENT

            STOCKHOLDERS AGREEMENT (the "Agreement"), dated as of July 10, 2001
by and among (i) Williams Communications, LLC, a Delaware limited liability
company ("Williams"), (ii) iBeam Broadcasting Corporation, a Delaware
corporation (the "Company"), (iii) the other stockholders of the Company set
forth on the signature page hereto (the "Other Stockholders") and (iii) each
other Person (defined below) who becomes a party to this Agreement in accordance
with the terms hereof.

                              W I T N E S S E T H:

            WHEREAS, this Agreement shall become effective (the "Effective
Date") on the date of, and simultaneously with, the closing under the Stock
Purchase Agreement, dated as of June 24, 2001 between the Company, Williams and
the Other Stockholders (the "Stock Purchase Agreement");

            WHEREAS, on the Effective Date, (i) the authorized capital stock of
the Company will consist of 413,000,000 shares of common stock, $.0001 par value
(the "Common Stock"), and 10,000,000 shares of preferred stock, $.0001 par value
(the "Preferred Stock") of which 3,000,000 shares will be designated Series A
Convertible Preferred Stock, $.0001 par value (the "Series A Preferred Stock")
and (ii) the issued and outstanding capital stock of the Company will consist of
127,353,381 shares of Common Stock and 2,400,939 shares of Series A Preferred
Stock, with 240,930,900 shares of Common Stock reserved for issuance upon the
exercise of certain stock options and warrants and upon conversion of the Series
A Preferred Stock; and

            WHEREAS, on the Effective Date Williams shall hold 1,800,704 shares
of Series A Preferred Stock and the Other Stockholders shall hold, in the
aggregate, 600,235 shares of Series A Preferred Stock;

            NOW THEREFORE, in consideration of the mutual covenants and
agreements herein contained, the parties hereto agree as follows:

<PAGE>

                                   ARTICLE I

                                  DEFINITIONS

            Section 1.1 Definitions. As used in this Agreement, the following
terms have the following meanings:

            "Affiliate" as applied to any Person, shall mean any other Person
directly or indirectly controlling or controlled by or under, direct or
indirect, common control with such Person. For the purposes of this definition,
control when used with respect to any Person means the power to direct the
management and policies of such person, directly or indirectly, whether through
the ownership of voting securities, by contract or otherwise; and the terms
"controlling" and "controlled" have meanings correlative to the foregoing.
Notwithstanding the foregoing, neither Williams and its Affiliates nor the Other
Stockholders and their respective Affiliates shall be deemed Affiliates of the
Company for purposes of this Agreement.

            "beneficially own" and "beneficial ownership" have the meanings
given to them in Rule 13d-3 under the Exchange Act.

            "Board of Directors" shall mean the Board of Directors of the
Company.

            "Business Day" shall mean each day other than Saturdays, Sundays and
days when commercial banks are authorized to be closed for business in New York,
New York.

            "Certificate of Designations" shall mean the Certificate of
Designations of the Series A Preferred Stock attached hereto as Exhibits A.

            "Charter Documents" shall mean the Certificate of Incorporation and
By-Laws of the Company, in effect as of the Effective Date, attached hereto as
Exhibits B and C, respectively.

            "Commission" shall mean the United States Securities and Exchange
Commission.

            "Common Stock" shall have the meaning set forth in the recitals.

            "Company" shall have the meaning set forth in the preamble.


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<PAGE>

            "Company Offered Securities" shall have the meaning set forth in
Section 6.1.

            "Effective Date" shall have the meaning set forth in the recitals.

            "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended, and the rules and regulations promulgated thereunder.

            "Indebtedness" of any Person at any date shall include (i) all
indebtedness of such Person for borrowed money or for the deferred purchase
price of property or services, including earn-out or similar contingent purchase
amounts, (ii) any other indebtedness of such Person which is evidenced by a
note, mortgage, bond, debenture or similar instrument, (iii) all obligations of
such Person under capitalized leases, (iv) all payments made or to be made
pursuant to sale-leaseback transactions, (v) all payments made or to be made
pursuant to a non-compete payment obligation, change of control payment
obligation, and severance and retention obligations, and (vi) all guarantees by
such Person of obligations of others whether or not such Person has assumed or
otherwise become directly liable for the payment thereof.

            "MD&A" shall mean a management's discussion and analysis of the
Company's financial condition and results of operation comparable to the
discussion that is required to be included in periodic reports filed under the
Exchange Act.

            "Notices" shall have the meaning set forth in Section 8.6.

            "Permitted Transferee" shall mean with respect to any Person, any
other Person that is an Affiliate of the such Person.

            "Person" shall mean an individual or a corporation, limited
liability company, partnership, trust, or any other entity or organization,
including a government or political subdivision or an agency or instrumentality
thereof.

            "Preemptive Rights Offer" shall have the meaning set forth in
Section 6.1.

            "Preemptive Rights Offer Notice" shall have the meaning set forth in
Section 6.1.

            "Preemptive Rights Transaction" shall have the meaning set forth in
Section 6.1.


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<PAGE>

            "Preferred Stock" shall have the meaning set forth in the recitals.

            "Registration Rights Agreements" shall mean the Registration Rights
Agreement, dated as of the date hereof, by and between the Company, Williams and
the Other Stockholders, attached hereto as Exhibit D.

            "Securities Act" shall mean the Securities Act of 1933, as amended,
and the rules and regulations thereunder.

            "Series A Preferred Stock" shall have the meaning set forth in the
recitals.

            "Shares" shall mean, collectively, the Common Stock and the
Preferred Stock. Whenever this Agreement refers to a number or percentage of
Shares, such number or percentage shall be calculated as if each of the Shares
had been exchanged or converted into shares of Common Stock immediately prior to
such calculation regardless of the existence of any restrictions on or
conditions to such exchange or conversion.

            "Standstill Period" shall have the meaning set forth in Section 5.1.

            "Stock Purchase Agreement" shall have the meaning set forth in the
recitals.

            "Subsidiary" shall mean, with respect to any Person, (a) a
corporation a majority of whose capital stock with voting power, under ordinary
circumstances, to elect directors is at the time, directly or indirectly, owned
by such Person, by a Subsidiary of such Person, or by such Person and one or
more Subsidiaries of such Person, (b) a partnership in which such Person or a
Subsidiary of such Person is, at the date of determination, a general partner of
such partnership, or (c) any other Person in which such Person, a Subsidiary of
such Person or such Person and one or more Subsidiaries of such Person, directly
or indirectly, at the date of determination thereof, has (i) at least a majority
ownership interest or (ii) the power to elect or direct the election of the
directors or other governing body of such Person.

            "Transaction Documents" shall have the meaning set forth in the
Stock Purchase Agreement.

            "Transfer" shall mean (i) when used as a noun: any direct or
indirect transfer, sale, assignment, pledge, hypothecation, encumbrance or other
disposition


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<PAGE>

and (ii) when used as a verb: to directly or indirectly transfer, sell, assign,
pledge, hypothecate, encumber, or otherwise dispose of.

            "Transferee" shall mean any Person to whom Shares have been
Transferred in compliance with the terms of this Agreement.

            "Voting Stock" means the capital stock of any class or kind
ordinarily having the power to vote generally for the election of directors (or
other persons or bodies performing similar functions) of the Company. With
respect to the Company, as of the Effective Date, Voting Stock includes (i) the
Common Stock, and (ii) the Series A Preferred Stock.

            "Williams Nominees" shall have the meaning set forth in Section
4.l(a).

                                   ARTICLE II

                           RESTRICTIONS ON TRANSFERS

            Section 2.1 Transfers in Accordance with this Agreement. Any attempt
to Transfer, or purported Transfer of, any of the Shares held by Williams, the
Other Stockholders or their respective Permitted Transferees in violation of the
terms of this Agreement shall be null and void and the Company shall not
register upon its books, and shall direct its transfer agent not to register on
its books any such Transfer. A copy of this Agreement shall be filed with the
Secretary of the Company and the Company's transfer agent and kept with the
records of the Company.

            Section 2.2 Restrictions on Transfer.

                  (a) Except as set forth below, prior to the second anniversary
of the date hereof, Williams and its Permitted Transferees shall not Transfer
any Shares except (i) to a Permitted Transferee, (ii) pursuant to an effective
registration statement filed with the Commission (including a registration
statement contemplated by the Registration Rights Agreement) or (iii) to any
other stockholder of the Company who is bound by the terms of this Agreement.

                  (b) Following the second anniversary hereof and subject to the
other terms of this Agreement, Williams and its Permitted Transferees may,
subject to applicable law, Transfer any Shares to any Person, provided that if
such Transferee is not a Permitted Transferee then such Transferee must, to the
extent it becomes a


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<PAGE>

party to this Agreement, agree that it waives and otherwise has no rights under
Section 4.2(b). Subject to the other terms of this Agreement, after the date
hereof, the Other Stockholders and their respective Permitted Transferees may,
subject to applicable law, Transfer any Shares to any Person. Prior to any
Transfer of Shares by Williams, an Other Stockholder or their Permitted
Transferees which is not registered under the Securities Act, the proposed
transferor shall give written notice to the Company of such transferor's
intention to effect such Transfer. Each such notice shall describe the manner of
the proposed Transfer. If within three (3) Business Days after receipt by the
Company of such notice, the Company requests in writing an opinion of counsel
for such transferor that the proposed Transfer may be effected without
registration of such Shares under the Securities Act, then prior to Transferring
such Shares, such transferor shall provide the Company an opinion of counsel
(which counsel and opinion shall each be reasonably satisfactory to the Company)
that such Transfer may be effected without registration of such Shares under the
Securities Act.

                  (c) No Transfer provided in the foregoing clauses (a) and (b)
of this Section 2.2 (other than pursuant to an effective registration statement
filed with the Commission) shall be permitted unless (i) the certificates
representing such Shares issued to the Transferee bear the legend provided in
Section 2.3 and (ii) the Transferee (if not already a party hereto) has executed
and delivered to each other party hereto, as a condition precedent to such
Transfer, an instrument or instruments, reasonably satisfactory to the Company,
confirming that the Transferee agrees to be bound by the terms of this Agreement
in the same manner as such Transferee's transferor, except as otherwise provided
in this Agreement.

                  (d) The Company agrees that it will not unreasonably deny any
request for a waiver of the restrictions set forth in this Section 2.2 made by
Williams, the Other Stockholders or their respective Permitted Transferees.

            Section 2.3 Legend. Williams and the Other Stockholders hereby agree
that each outstanding certificate representing Shares issued to it and its
Permitted Transferees, or any certificate issued in exchange for or upon
conversion of any similarly legended certificate, shall bear a legend reading
substantially as follows:

      THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
      THE SECURITIES ACT OF 1933, AS AMENDED, OR UNDER ANY STATE SECURITIES
      LAWS, AND MAY BE OFFERED AND SOLD ONLY IF SO REGISTERED OR AN EXEMP-


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<PAGE>

      TION FROM REGISTRATION IS AVAILABLE. THE SHARES REPRESENTED BY THIS
      CERTIFICATE ALSO ARE SUBJECT TO ADDITIONAL RESTRICTIONS ON TRANSFER AS SET
      FORTH IN THE STOCKHOLDERS AGREEMENT, DATED AS OF JULY 10, 2001, A COPY OF
      WHICH MAY BE OBTAINED FROM THE COMPANY. NO TRANSFER OF SUCH SHARES WILL BE
      MADE ON THE BOOKS OF THE COMPANY UNLESS ACCOMPANIED BY EVIDENCE OF
      COMPLIANCE WITH THE TERMS OF SUCH AGREEMENT AND BY AN AGREEMENT OF THE
      TRANSFEREE TO BE BOUND BY THE RESTRICTIONS SET FORTH IN THE STOCKHOLDERS
      AGREEMENT.

            Section 2.4 Right of First Refusal.

                  (a) Except with respect to a Transfer of Common Stock pursuant
to an effective registration statement in an underwritten public offering (which
will be subject to Section 2.5 below), if at any time Allen & Company
Incorporated, Touch America, Inc. or any their respective Permitted Transferees
(each, an "Offeror") proposes to Transfer any Shares to any Person other than to
one of its Permitted Transferees (such Person, a "Third Party"), the Offeror
shall, before such Transfer, deliver to Williams an offer (the "Offer") to
Transfer such Shares to Williams upon the terms set forth in this Section 2.4.
The Offer shall (i) state that the Offeror proposes to Transfer the Shares, (ii)
specify the number of Shares (the "Offered Shares") proposed to be Transferred,
and (iii) state the terms (including the purchase price) of the proposed
Transfer. The Offer shall remain open and irrevocable for a period of fifteen
(15) days (the "Acceptance Period") from the date of its receipt by Williams.

                  (b) Williams may accept the Offer by delivering to the Offeror
written notice within the Acceptance Period, which notice shall state the number
(the "Accepted Number") of Offered Shares Williams desires to purchase. Williams
may exercise its right to purchase any or all of the Offered Shares pursuant to
the Offer.

                  (c) The Transfer of Offered Shares to Williams, to the extent
Williams has exercised its rights under this Section 2.4, shall be made on a
business day, as designated by the Offeror, not less than 10 nor more than 30
days after expiration of the Acceptance Period on the terms and conditions
specified in the Offer, which terms and conditions shall be identical to the
terms of the proposed Transfer to the Third Party.


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<PAGE>

                  (d) If the number of Offered Shares exceeds the Offered Shares
with respect to which Williams exercised its rights under this Section 2.4, the
Offer shall be deemed to be withdrawn with respect to such excess and the
Offeror may Transfer, subject to the provisions of Section 2 hereof, such excess
Offered Shares on the terms, conditions and purchase price specified in the
Offer (which shall be the same terms, conditions and purchase price available to
Williams exercising rights pursuant to this Section 2) to any Third Party within
60 days after expiration of the Acceptance Period, so long as such Third Party
agrees in writing to become a party hereto and be bound hereby. If such Transfer
is not made within such 60-day period, the restrictions provided for in this
Section 2 shall again become effective.

                  (e) In the event an Offeror or such Third Party, as the case
may be, shall modify the terms of the proposed Transfer of Offered Shares in any
way, the Offeror shall send an amended Offer to Williams. Williams shall, if it
so desires to exercise its right of Offer, as so amended, prior to the later of
five (5) days after the date such amended Offer is received by the Company or
the end of the original Acceptance Period, deliver to the Offeror an amended
notice of acceptance specifying the amended Accepted Number and/or such other
amended term of Williams' acceptance pursuant to this Section 2.

                  (f) This Section 2.4 is subject to Article V. Accordingly, to
the extent that Williams and its Permitted Transferees are prohibited from
acquiring Offered Shares as a result of the restrictions imposed by Article V,
Williams shall have the right to assign (without the consent of the other
parties hereto) its right to purchase such Offered Shares to any Person who is
not an Affiliate of Williams, provided that (i) such Person agrees to be bound
by the terms of this Agreement, including Section 2.4 and Section 2.5, and (ii)
such Person has the financial capability to purchase such Offered Shares. In the
event that Williams does not purchase any or all of the Offered Shares and the
Offeror Transfers such Offered Shares to a Third Party (other than pursuant to
an effective registration statement) then, prior to such Transfer, such Third
Party must agree to be bound by the terms of this Agreement, including Section
2.4 and Section 2.5.

            Section 2.5 Right of First Offer in Underwritten Offering.

                  (a) If at any time an Offeror proposes to Transfer any shares
of Common Stock to a Third Party pursuant to an effective registration statement
in an underwritten public offering, the Offeror shall, before such Transfer,
deliver to Williams an offer (the "Underwritten Offer") to Transfer to Williams,
upon the terms set forth in this Section 2.5, (i) such shares of Common Stock,
(ii) if such Offeror


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<PAGE>

then holds shares of Series A Preferred Stock, such number of shares of Series A
Preferred Stock which, upon conversion into shares of Common Stock, would equal
the number of shares of Common Stock proposed to be Transferred pursuant to an
effective registration statement in such underwritten public offering, and (iii)
if such Offeror then holds shares of both Common Stock and Series A Preferred
Stock, a combination of shares of Common Stock and Series A Preferred Stock
which, on an as if converted basis, is equal to the number of shares of Common
Stock proposed to be Transferred pursuant to an effective registration statement
in such underwritten public offering. The Underwritten Offer shall (i) state
that the Offeror proposes to Transfer the shares of Common Stock and Series A
Preferred Stock, as the case may be, (ii) specify the number of shares of Common
Stock and Series A Preferred Stock, as the case may be, proposed to be
Transferred (the "Underwritten Offered Shares"), and (iii) state the terms of
the proposed Transfer (including the per share purchase price as determined in
Section 2.5(c)). The Underwritten Offer shall remain open and irrevocable for a
period of fifteen (15) days (the "Underwritten Acceptance Period") from the date
of its receipt by Williams. At the time of delivery of the Underwritten Offer to
Williams, the Offeror must have a bona fide intention to Transfer such shares of
Common Stock pursuant to an effective registration statement in an underwritten
public offering within 105 days of delivery of such Underwritten Offer.

                  (b) Williams may accept the Underwritten Offer by delivering
to the Offeror written notice (the "Underwritten Acceptance Notice") within the
Underwritten Acceptance Period, which notice shall state the number of
Underwritten Offered Shares Williams desires to purchase. Williams may exercise
its right to purchase any or all of the Underwritten Offered Shares pursuant to
the Underwritten Offer. The actual combination of shares of Common Stock and
Series A Preferred Stock referred to in clause (iii) of the first sentence of
Section 2.5(a) shall be determined by Williams in its sole discretion based on
the shares of Common Stock and Series A Preferred Stock held by the Offeror at
the time of the Underwritten Offer is received by Williams.

                  (c) The per share purchase price of the Underwritten Offered
Shares shall be determined as follows: (i) for Underwritten Offered Shares which
are Common Stock, the per share purchase price of such Underwritten Offered
Shares shall be the average per share Closing Price (as defined below) of the
Common Stock during the period beginning on the date of receipt by Williams of
the Underwritten Offer and ending on the date Williams delivers to the Offeror
the Underwritten Acceptance Notice (the "Common Stock Purchase Price"), and (ii)
for Underwritten Offered Shares which are Series A Preferred Stock, the per
share purchase price of such Underwritten Offered Shares shall be the product of
(A) the Common Stock


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<PAGE>

Purchase Price, and (B) the number equal to the number of shares of Common Stock
into which each share of Series A Preferred Stock is convertible on the
Underwritten Closing Date (as defined below). "Closing Price" means, as to any
particular day, the average closing prices on such day of the sales of Common
Stock on all domestic securities exchanges on which the Common Stock may at the
time be listed, or, if there have been no sales on any such exchanges on any
day, the average of the highest bid and lowest asked prices on all such
exchanges at the end of such day, or, if on any day the Common Stock is not so
listed on a domestic securities exchange, the average of the representative bid
and asked prices quoted on the NASDAQ Stock Market as of 4:00 P.M., New York
City time, on such day, or, if on any day the Common Stock is not listed on a
domestic securities exchange or quoted on the NASDAQ Stock Market, the average
of the highest bid and lowest asked prices on such day in the domestic
over-the-counter market as reported by the National Quotation Bureau,
Incorporated, or any similar or successor organization (and in each such case
excluding any trades that are not bona fide, arm's-length transactions).

                  (d) The Transfer of Underwritten Offered Shares to Williams,
to the extent Williams has exercised its rights under this Section 2.5, shall be
made on a business day, as designated by Williams, not less than 10 nor more
than 30 days after expiration of the Underwritten Acceptance Period (the
"Underwritten Closing Date") on the terms and conditions specified in the
Underwritten Offer.

                  (e) If the number of Underwritten Offered Shares exceeds the
Underwritten Offered Shares with respect to which Williams exercised its rights
under this Section 2.5, the Underwritten Offer shall be deemed to be withdrawn
with respect to such excess and the Offeror may Transfer, subject to the
provisions of Section 2 hereof, such excess Underwritten Offered Shares to any
Third Party, provided that such Transfer is made pursuant to an effective
registration statement in an underwritten public offering within 90 days after
expiration of the Acceptance Period. If such Transfer is not made pursuant to an
effective registration statement in an underwritten public offering within such
90-day period, the restrictions provided for in this Section 2 shall again
become effective.


                  (f) This Section 2.5 is subject to Article V. Accordingly, to
the extent that Williams and its Permitted Transferees are prohibited from
acquiring Underwritten Offered Shares as a result of the restrictions imposed by
Article V, Williams shall have the right to assign (without the consent of the
other parties hereto) its right to purchase such Underwritten Offered Shares to
any Person who is not an Affiliate of Williams, provided that (i) such Person
agrees to be bound by the


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<PAGE>

terms of this Agreement, including Section 2.4 and Section 2.5, and (ii) such
Person has the financial capability to purchase such Underwritten Offered
Shares.

                                  ARTICLE III

                      ADDITIONAL RIGHTS AND OBLIGATIONS OF
                WILLIAMS, THE OTHER STOCKHOLDERS AND THE COMPANY

            Section 3.1 Access to Information; Confidentiality. Upon the request
of Williams, the Company shall afford Williams and its accountants, counsel and
other representatives reasonable access to all of the properties, books,
contracts, commitments and records (including, but not limited to, tax returns)
of the Company and its Subsidiaries that are reasonably requested. Williams
will, and will cause its agents and other representatives to, conduct any such
investigations on reasonable advance notice, during normal business hours, with
reasonable numbers of persons and in such a manner as not to interfere
unreasonably with the normal operations of the Company and its Subsidiaries.
Except as otherwise required by applicable law, neither the Company nor any of
its Subsidiaries shall be required to provide access to or to disclose
information where such access or disclosure would jeopardize the attorney-client
privilege of the Person in possession or control of such information, or would
violate any applicable law. The parties hereto will make appropriate substitute
disclosure arrangements under circumstances in which the restrictions of the
preceding sentence apply. Williams shall, and shall use its reasonable best
efforts to cause its representatives to, keep confidential all such information
to the same extent such information is treated as confidential by the Company.
The obligation to keep such information confidential shall not apply to (i) any
information that (x) was already in Williams' possession prior to the disclosure
thereof by the Company, (y) was then generally known to the public, or (z) was
disclosed to Williams by a third party not known by Williams to be bound by an
obligation of confidentiality or (ii) disclosures made as required by law, legal
process or stock exchange rule. If either Williams or its Affiliates is
nonetheless, in the opinion of their respective counsel, compelled to disclose
information concerning the Company to any tribunal or governmental body or
agency or else stand liable for contempt or suffer other censure or penalty,
Williams and such Affiliate may disclose such information to such tribunal or
governmental body or agency without liability hereunder.


            Section 3.2 Furnishing of Information. (a) The Company shall deliver
to Williams and the Other Stockholders, as the case may be, as long as such
Person (together with its Permitted Transferees) beneficially owns in the
aggregate


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<PAGE>

10% or more of the Shares issued pursuant to the Stock Purchase Agreement on the
Effective Date:

                        (i) As promptly as practical, but in no event later than
      30 days after the end of each calendar month, a copy of the monthly
      financial reporting package for such month customarily prepared for the
      Company's Chief Executive Officer;

                        (ii) As promptly as practical, but in no event later
      than 45 days after the close of each of its first three quarterly
      accounting periods during any fiscal year of the Company, the consolidated
      balance sheet of the Company as at the end of such quarterly period, and
      the related consolidated statements of operations, stockholders' equity
      and cash flows for such quarterly period, and for the elapsed portion of
      the fiscal year ended with the last day of such quarterly period, and in
      each case setting forth comparative figures for the related periods in the
      prior fiscal year all of which shall be certified by the Chief Financial
      Officer of the Company, to have been prepared in accordance with generally
      accepted accounting principles, subject to year-end audit adjustments,
      together with an MD&A;

                        (iii) As promptly as practical, but in no event later
      than 90 days after the close of each fiscal year of the Company, the
      consolidated balance sheet of the Company as of the end of such fiscal
      year and the related consolidated statements of operations, stockholders'
      equity and cash flows for such fiscal year, in each case setting forth
      comparative figures for the preceding fiscal year, and certified by
      independent certified public accountants of recognized national standing,
      together with an MD&A; and

                        (iv) All reports, if any, filed by the Company or any
      Subsidiary of the Company with the Commission under the Exchange Act, as
      promptly as practical, but in no event later than 5 days after filing any
      such reports with the Commission.


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<PAGE>

                                   ARTICLE IV

                        CORPORATE GOVERNANCE AND VOTING

            Section 4.1 Board of Directors of the Company.

                  (a) The Company and its directors have taken all appropriate
and necessary action to (i) cause the Board of Directors of the Company, as of
the Effective Date, to be composed of nine (9) members and divided into three
(3) classes designated as Class I, Class II and Class III, each class consisting
of three (3) directors, and (ii) reclassify one of the existing Class III
directors as a Class II director. For so long as Williams, together with any and
all of its Permitted Transferees, beneficially own in the aggregate 25% or more
of the Shares beneficially owned by Williams on the Effective Date, the size of
the Board of Directors shall not exceed nine (9) members. Williams shall be
entitled to nominate four members to the Board of Directors (collectively, the
"Williams Nominees"). One Williams Nominee shall be classified as a Class I
Director of the Company, two Williams Nominees shall be classified as Class II
Directors of the Company and one Williams Nominees shall be classified as a
Class III Director of the Company.

                  (b) The Company and its directors have taken all appropriate
action to cause the appointment of the Williams Nominees to become effective as
of the Effective Date. For so long as Williams, together with any and all of its
Permitted Transferees, beneficially own in the aggregate 25% or more of the
Shares beneficially owned by Williams on the Effective Date, Williams, the Other
Stockholders and each of their Permitted Transferees shall vote all of its
Voting Stock of the Company, and shall take all other necessary or desirable
actions within their control, and the Company shall take all necessary or
desirable action within its control, to cause the Williams Nominees to be
nominated for and elected to the Board of Directors.

                  (c) The Company shall use its best efforts to call, or cause
the appropriate officers and directors of the Company, to call, a special
meeting of stockholders of the Company, as applicable, to cause the removal
(with or without cause) of any Williams Nominee if Williams requests such
director's removal in writing for any reason and the Other Stockholders agree to
vote their Voting Stock to remove such director. Williams shall have the right
to designate a new nominee in the event any Williams Nominee shall be so removed
under this Section 4.1(c) or shall vacate his directorship for any reason.


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<PAGE>

                  (d) The initial Williams Nominees shall be Howard Janzen, John
Bumgarner, Jr., Laura Kenny and Paul Gould. Any other person designated by
Williams as a Williams Nominee shall either be (x) an employee or director of
Williams or its Affiliates or (y) if not such an employee or director of
Williams or its Affiliates, a person who is reasonably acceptable to the
Company.

                  (e) At such time as Williams, together with any and all of its
Permitted Transferees, cease to beneficially own in the aggregate 50% or more of
the Shares beneficially owned by Williams on the Effective Date but such Persons
beneficially own in the aggregate 25% or more of the Shares beneficially owned
by Williams on the Effective Date, Williams shall be entitled to nominate only
three Williams Nominees in accordance with this Section 4. At such time as
Williams, together with any and all of its Permitted Transferees, cease to
beneficially own in aggregate 25% or more of the Shares beneficially owned by
Williams on the Effective Date but such Persons beneficially own in the
aggregate 10% or more of the Shares beneficially owned by Williams on the
Effective Date, Williams shall be entitled to nominate only two Williams
Nominees in accordance with this Section 4. At such time as Williams, together
with any and all of its Permitted Transferees, cease to beneficially own in
aggregate 10% or more of the Shares beneficially owned by Williams on the
Effective Date, Williams shall no longer be entitled to nominate any Williams
Nominees in accordance with this Section 4. Williams shall take all appropriate
action to cause one or more of the Williams Nominees to resign as a director of
the Company as necessary to comply with this Section 4.1(e).

                  (f) The Company, the Other Stockholders and Williams shall
take all such action to cause one of the Williams Nominees to be Chairman of the
Compensation Committee of the Board of Directors.

                  (g) The Company and its directors have established, and will
continue to take all such action necessary to maintain, an Executive Committee
of the Board of Directors, comprised of three members as follows (i) the
Company's Chief Executive Officer, (ii) an executive vice president or more
senior executive officer of the Company who is also a director of the Company
and (iii) a Williams Nominee, provided that the right of Williams to have a
Williams Nominee on the Executive Committee of the Board of Directors shall be
effective only during such periods of time that Williams is entitled to have
three or more nominees on the Board of Directors. The duties of the Executive
Committee shall be established by the Board of Directors and shall include,
among other things, the development of the Company's annual business plan, which
plan shall be submitted to the Board of Directors for approval each fiscal year.
As long as Williams, together with any and


                                       14
<PAGE>

all of its Permitted Transferees, beneficially owns, in the aggregate, at least
aggregate 25% or more of the Shares beneficially owned by Williams on the
Effective Date, the annual business plan of the Company and any material
adjustments to such plan shall require the affirmative vote of a majority of the
entire Board of Directors and the affirmative vote of each Williams Nominee. In
the event that the Company's annual business plan and any material adjustments
thereto is not approved by the requisite vote set forth in the previous
sentence, the annual business plan of the Company shall revert back to the
Company's previous annual business plan, or in the case of any material
adjustments, shall not be so adjusted. The Executive Committee shall have
authority, subject to applicable law, to take all actions that (A) are ancillary
to or arise in the normal course of the businesses of the Company, and (B)
implement and are consistent with resolutions of the Board of Directors,
provided, however, that such Executive Committee shall not be authorized to take
any action which, if proposed to be taken by the full Board of Directors, would
require the affirmative vote of the Williams Nominees in accordance with Section
4.2. Each committee of the Board of Directors shall include a proportionate
number of Williams nominees equal to the percentage of Williams nominees on the
entire Board of Directors.

                  (h) In the event that a director on the Board who is an
"independent director" under the rules and regulations of the Nasdaq Stock
Market (other than any Williams Nominee) resigns, is removed from office or
otherwise ceases to be a director, the Company shall, and Williams and the Other
Stockholders shall take such action within their respective control to cause the
Company to, comply with the "independent director" requirements of The Nasdaq
Stock Market, and the Company shall have the right to approve the replacement of
such "independent director." So long as Williams beneficially owns less than a
majority of the outstanding Voting Stock, Williams agrees that (i) it shall not
call a special meeting of the Company's stockholders or take any other action
for the purpose of removing the non-Williams Nominees on the Board of Directors,
and (ii) in the event a non-Williams Nominee resigns, is removed from office or
otherwise ceases to be a director, the remaining non-Williams Nominees on the
Board of Directors shall have the right to appoint a replacement director.

                  (i) Each committee of the Board of Directors, to which
authority has been delegated, shall keep complete and accurate minutes and
records of all actions taken by such committee, prepare such minutes and records
in a timely fashion and promptly distribute such minutes and records to each
member of the Board of Directors.


                                       15
<PAGE>

                  (j) The parties agree that upon the request of Williams, the
Company shall cause the Board of Directors of any Subsidiary of the Company to
include such number of individuals designated by Williams in the same proportion
of the total number of members of the Board of Directors of such Subsidiary as
the proportion of the Company's Board of Directors to which Williams is entitled
pursuant to Section 4.1.

            Section 4.2 Action by the Board of Directors.

                  (a) Except as provided herein, all decisions of the Board of
Directors shall require the affirmative vote of a majority of the directors of
the Company then in office, or a majority of the members of an Executive
Committee of the Board of Directors, to the extent such decisions may be
delegated to an Executive Committee pursuant to applicable law and Section
4.1(g).

                  (b) As long as Williams, together with any and all of its
Permitted Transferees, beneficially owns in aggregate 40% or more of the Shares
beneficially owned by Williams on the Effective Date, without the affirmative
vote of each of the Williams Nominees, the Company shall not, and it shall cause
each of its Subsidiaries not to, directly or indirectly, (i) incur a significant
amount of Indebtedness in the aggregate (which for purposes of this clause (i),
any amount in excess of $10 million in the aggregate shall be deemed to be
significant); (ii) redeem, purchase or otherwise acquire for value, or set apart
money or other property for any mandatory purchase or other similar fund for the
redemption, purchase or acquisition of any shares of Common Stock or Junior
Stock (as defined in the Certificates of Designations), except for the
repurchase by the Company of up to 5% of the outstanding Common Stock of the
Company outstanding on the Effective Date; (iii) declare or pay any dividend or
make any distribution (whether in cash, shares of capital stock of the Company,
or other property) on shares of Common Stock or Junior Stock; (iv) sell, lease,
license or otherwise dispose of, in any single transaction or series of related
transactions, a significant amount of the property and other assets of the
Company, (v) amend, alter or repeal, in any manner whatsoever, the designations,
preferences, privileges and relative rights and limitations and restrictions of
the Series A Preferred Stock, (vi) increase or decrease the number of authorized
shares of Common Stock or Preferred Stock, (vii) enter into any transaction
which results, directly or indirectly, in the sale, merger, consolidation or
corporate reorganization of, or other similar transaction involving, the
Company, including, without limitation, any transaction which would result in a
Change in Control (as defined in the Certificates of Designations) of the
Company, (viii) create (by reclassification or otherwise), authorize or issue
any new class or series of equity security having


                                       16
<PAGE>

designations, preferences, privileges or rights senior to, or on parity with,
the Series A Preferred Stock, (ix) create (by reclassification or otherwise),
authorize or issue any class, series or shares of capital stock or other
securities junior to the Series A Preferred Stock if such junior securities may
be redeemed in any circumstance on or prior to the Final Redemption Date (as
defined in the Certificates of Designations"), (x) amend, alter or repeal any of
the provisions of the Charter Documents or the Certificates of Designations in a
manner that would adversely affect the holders of the Series A Preferred Stock;
(xi) adopt, and if adopted, amend or waive any provision of, a shareholder
rights plan or similar plan or agreement, (xii) effect a voluntary liquidation,
dissolution or winding up of the Company; or (xiii) voluntarily file for
bankruptcy, or otherwise seek protection under any federal or state bankruptcy
or similar law.

                  (c) Until the 6th month anniversary of the date hereof, any
termination of Nicholas Baletta's, Robert Davis' or Scott Klososky's employment
by the Company without Cause (as defined in the Company's Retention Bonus Plan)
shall require the affirmative vote of a majority of the Board of Directors.
Notwithstanding anything to the contrary herein, the approval of the termination
of such persons employment may not be delegated to a committee of the Board of
Directors.

            Section 4.3 Certificates of Designations; Charter Documents. (a) The
Certificate of Designations, as in effect on the date hereof, is set forth in
Exhibit A hereto. The Charter Documents, as in effect on the date hereof, are
set forth in Exhibits B and C hereto.

                  (b) The Company covenants that it will act in accordance with
its Charter Documents and the Certificate of Designations. The Company shall
take all action necessary, to ensure that (i) the Charter Documents and
Certificate of Designations do not, at any time, conflict with the provisions of
this Agreement, and (ii) unless an amendment is approved by the Board of
Directors in accordance with Section 4.2, the Charter Documents and the
Certificate of Designations continue to be in effect in the forms attached
hereto.

            Section 4.4 Meetings of Stockholders. The Other Stockholders and
Williams agree that their representatives shall meet, either in person or by
teleconference, at least five (5) Business Days prior to any meeting of
stockholders of the Company to discuss their respective views and opinions with
regard to the matters proposed for consideration at such stockholders meeting.


                                       17
<PAGE>

                                   ARTICLE V

                                   STANDSTILL

            Section 5.1 Standstill (a) Without the prior written consent of the
Company or except as provided in this Agreement, from the date hereof until the
second anniversary of the date hereof (the "Standstill Period"), each of
Williams and the Other Stockholders shall not, and shall not permit any of their
respective Permitted Transferees or other Affiliates to, acquire, publicly
announce an intention to acquire, or agree to acquire beneficial ownership of
any Voting Stock of the Company resulting in an increase in their respective
percentage beneficial ownership, at such time, of the Company's Voting Stock on
a fully diluted basis.

            (b) Notwithstanding anything in this Agreement (including this
Section 5.1) to the contrary, during the Standstill Period, (i) each of
Williams, the Other Stockholders and their respective Permitted Transferees and
other Affiliates may acquire additional Voting Stock upon the conversion or
exchange of the Series A Preferred Stock, (ii) each of Williams, the Other
Stockholders and their respective Permitted Transferees and other Affiliates
may, subject to compliance with applicable law, propose, announce and otherwise
make an offer to purchase all of the outstanding capital stock of the Company
and pursuant to such offer acquire such shares of capital stock, and (iii) each
of Williams, the Other Stockholders and their respective Permitted Transferees
and other Affiliates may make open market purchases of the Company's Voting
Stock as may be necessary for such Persons (either directly or through its
Permitted Transferees) to maintain their respective fully-diluted ownership
percentage of the Company's Voting Stock existing on the date hereof. The
Company agrees that it will not unreasonably deny any request for a waiver of
the restrictions set forth in this Article V made by Williams, the Other
Stockholders or their respective Permitted Transferees.

                                   ARTICLE VI

                               PREEMPTIVE RIGHTS

            Section 6.1 Preemptive Rights.

                  (a) In case the Company proposes at any time to issue or sell
any shares of equity securities of the Company (or securities convertible or
exchangeable for equity securities of the Company) issued by the Company after
the date hereof (collectively, the "Company Offered Securities"), the Company
shall, no


                                       18
<PAGE>

later than twenty (20) days prior to the consummation of such transaction (a
"Preemptive Rights Transaction"), give notice in writing (the "Preemptive Rights
Offer Notice") to Williams, the Other Stockholders and their respective
Permitted Transferees of such Preemptive Rights Transaction. The Preemptive
Rights Offer Notice shall describe the proposed Preemptive Rights Transaction,
identify the proposed purchaser or purchasers, and contain an offer (the
"Preemptive Rights Offer") to sell Williams, the Other Stockholders and their
respective Permitted Transferees, at the same price and for the same
consideration to be paid by the proposed purchaser (provided, that, in the event
any of such consideration is non-cash consideration, at the election of
Williams, the Other Stockholders or their respective Permitted Transferees to
whom the Preemptive Rights Offer is made, Williams, the Other Stockholders and
their respective Permitted Transferees may pay cash equal to the value of such
non-cash consideration), all or any part of Williams', the Other Stockholders'
and their respective Permitted Transferees' pro rata portion of the Company
Offered Securities (which shall be a fraction of the Company Offered Securities
determined by dividing the number of shares of outstanding Voting Stock owned by
Williams, the Other Stockholders or such of their Permitted Transferees, as the
case may be, by the total number of outstanding shares of Voting Stock). If
Williams, the Other Stockholders or their respective Permitted Transferees to
whom a Preemptive Rights Offer is made fail to accept (each a "Non-Responding
Holder") in writing the Preemptive Rights Offer by the fifteenth (15th) day
after the Company's delivery of the Preemptive Rights Offer Notice, such
Non-Responding Holders shall have no further rights with respect to the proposed
Preemptive Rights Transaction and the Company may proceed with the proposed
Preemptive Rights Transaction, free of any right on the part of such
Non-Responding Holders, as the case may be, under this Section 6 in respect
thereof.

                  (b) The parties hereto agree that preemptive rights granted
pursuant to paragraph (a) of this Section 6.1 shall not be effective for
issuances of shares of Common Stock pursuant to the Company's 2000 Employee
Stock Purchase Plan, in accordance with the terms of such plan as in effect on
the date hereof and without giving effect to any amendment, alteration or repeal
of any of the terms of such plan or any increase in the number of shares of
Common Stock reserved for issuance under such plan.


                                       19
<PAGE>

                                  ARTICLE VII

                                  TERMINATION

            Section 7.1 Termination. Except as otherwise provided herein with
respect to certain specific provisions, this Agreement shall terminate upon the
earlier to occur of:

                        (i) the mutual agreement of Williams and the Company,

                        (ii) Williams and its Permitted Transferees ceasing to
      beneficially own in the aggregate 10% or more of the Shares beneficially
      owned by Williams on the Effective Date, and

                        (iii) with respect to each Other Stockholder, such Other
      Stockholder and its Permitted Transferees ceasing to beneficially own in
      the aggregate 10% or more of the Shares beneficially owned by such Other
      Stockholder on the Effective Date.

                                  ARTICLE VIII

                                 MISCELLANEOUS

            Section 8.1 Consolidation. In the event that in the reasonable
judgment of Williams, Williams or its Affiliates are required to consolidate
their interest in the Company for financial accounting purposes, then, at the
request of Williams, the Company, the Other Stockholders and Williams shall
amend the terms of the Transaction Documents such that the neither Williams nor
its Affiliates are required to consolidate their interest in the Company for
financial accounting purposes.


            Section 8.2 No Inconsistent Agreements. The Company represents and
agrees that, as of the Effective Date, there is no (and from and after the
Effective Date they will not, and will cause its respective Subsidiaries and
Affiliates not to, enter into any) agreement with respect to any securities of
the Company or any of its Subsidiaries (and from and after the Effective Date
Company shall not take, or permit any of its Subsidiaries or Affiliates to take,
any action) that is inconsistent


                                       20
<PAGE>

with the rights granted to Williams and the Other Stockholders in this
Agreement. Without limiting the foregoing, the Company represents that there are
no existing agreements relating to the voting or registration of any equity
securities of the Company or any of its Subsidiaries other than the Company's
Third Amended and Restated Investors Rights Agreement dated April 28, 2000, and
there are no other existing agreements between the Company and any other holder
of Shares relating to the transfer of any equity securities of the Company or
any of its Subsidiaries.

            Section 8.3 Recapitalization. Exchanges, etc. If any capital stock
or other securities are issued in respect of, in exchange for, or in
substitution of, any Shares by reason of any reorganization, recapitalization,
reclassification, merger, consolidation, spin-off, partial or complete
liquidation, stock dividend, split-up, sale of assets, distribution to
stockholders or combination of the Shares or any other change in capital
structure of the Company, appropriate adjustments shall be made with respect to
the relevant provisions of this Agreement so as to fairly and equitably
preserve, as far as practicable, the original rights and obligations of the
parties hereto under this Agreement and the terms "Common Stock," "Preferred
Stock" and "Shares," each as used herein, shall be deemed to include shares of
such capital stock or other securities, as appropriate. Without limiting the
foregoing, whenever a particular number of Shares is specified herein, such
number shall be adjusted to reflect stock dividends, stock-splits, combinations
or other reclassifications of stock or any similar transactions.

            Section 8.4 Successors and Assigns. This Agreement shall be binding
upon and shall inure to the benefit of the parties hereto, and their respective
successors and permitted assigns; provided that (i) neither this Agreement nor
any rights or obligations hereunder may be transferred or assigned by the
Company; and (ii) neither this Agreement nor any rights or obligations hereunder
may be transferred or assigned by Williams or the Other Stockholders except (A)
to any Person to whom it has Transferred Shares in compliance with this
Agreement and who has become bound by this Agreement pursuant to Section 2.2
hereof, and (B) to any Person pursuant Section 2.4(f).


            Section 8.5 No Waivers; Amendments. (a) No failure or delay by any
party in exercising any right, power or privilege hereunder shall operate as a
waiver thereof, nor shall any single or partial exercise thereof preclude any
other or further exercise thereof or the exercise of any other right, power or
privilege. The rights and remedies herein provided shall be cumulative and not
exclusive of any rights or remedies provided by law.


                                       21
<PAGE>

                  (b) This Agreement may not be amended or modified, nor may any
provision hereof be waived, other than by a written instrument signed by the
Company and Williams, provided that any amendment, modification or waiver that
materially and adversely affects the rights of one of the Other Stockholders
hereunder shall require the written consent of such Other Stockholder.

            Section 8.6 Notices. All notices, demands, requests, consents or
approvals (collectively, "Notices") required or permitted to be given hereunder
or which are given with respect to this Agreement shall be in writing and shall
be personally delivered or mailed, registered or certified, return receipt
requested, postage prepaid (or by a substantially similar method), or delivered
by a reputable overnight courier service with charges prepaid, or transmitted by
hand delivery or facsimile, addressed as set forth below, or such other address
(and with such other copy) as such party shall have specified most recently by
written Notice. Notice shall be deemed given or delivered on the date of service
or transmission if personally served or transmitted by facsimile. Notice
otherwise sent as provided herein shall be deemed given or delivered on the
third business day following the date mailed or on the next business day
following delivery of such Notice to a reputable overnight courier service.

                  To the Company:

                           iBeam Broadcasting Corporation
                           645 Almanor Avenue, Suite 100
                           Sunnyvale, California 94085
                           Attn:  General Counsel
                           Fax:   (408) 524-0567

                  with a copy (which shall not constitute notice) to:

                           Orrick, Herrington & Sutcliffe LLP
                           400 Sansome Street
                           San Francisco, CA 94111
                           Attn:  John F. Seegal, Esq.
                           Fax:  (415) 773-5759

                  To Williams:
                           Williams Communications, LLC
                           One Williams Center 41-3
                           Tulsa, Oklahoma  74172


                                       22
<PAGE>

                           Attn:  General Counsel
                           Fax: (918) 573-3005

                  with a copy (which shall not constitute notice) to:

                           Skadden, Arps, Slate, Meagher & Flom LLP
                           Four Times Square
                           New York, NY 10036
                           Attn: Alan C. Myers, Esq.
                           Fax:  (212) 735-2000

            To the Other Stockholders to the address and persons set forth on
the signature pages hereto.

            Section 8.7 Inspection. So long as this Agreement shall be in
effect, this Agreement and any amendments hereto and waivers hereof shall be
distributed to all parties hereto after becoming effective and shall be made
available for inspection at the principal office of the Company.

            Section 8.8 GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF DELAWARE. EACH PARTY
HERETO CONSENTS TO THE NON-EXCLUSIVE JURISDICTION OF THE FEDERAL AND STATE
COURTS WITHIN THE STATE OF DELAWARE.

            Section 8.9 Headings. The section headings contained in this
Agreement are for reference purposes only and shall not affect the meaning or
interpretation of this Agreement.

            Section 8.10 Entire Agreement. This Agreement, together with the
other Transaction Documents, constitutes the entire agreement and understanding
among the parties hereto with respect to the subject matter hereof and thereof
and supersedes any and all prior agreements and understandings, written or oral,
relating to the subject matter hereof.


            Section 8.11 Severability. Any term or provision of this Agreement
which is invalid or unenforceable in any jurisdiction shall, as to such
jurisdiction, be ineffective to the extent of such invalidity or
unenforceability without rendering invalid or unenforceable the remaining terms
and provisions of this Agreement or affecting the validity or enforceability of
any of the terms or provisions of this


                                       23
<PAGE>

Agreement in any other jurisdictions, it being intended that all rights and
obligations of the parties hereunder shall be enforceable to the fullest extent
permitted by law.

            Section 8.12 Counterparts. This Agreement may be signed in
counterparts, each of which shall constitute an original and which together
shall constitute one and the same agreement.

            Section 8.13 Required Approvals. If approval of this Agreement or
any of the transactions contemplated hereby shall be required by any
governmental agency or instrumentality or is considered to be necessary or
advisable by the parties hereto, all parties hereto shall use their reasonable
best efforts to obtain such approval.

            Section 8.14 Public Disclosure. The Company shall not, and shall not
permit any of its Subsidiaries to, make any public announcements or disclosures
relating or referring to Williams, the Other Stockholder or any of their
respective Affiliates, or any of their respective directors, officers, employees
or agents (including, without limitation, any Person designated as a director of
the Company pursuant to the terms hereof) unless such Person has consented to
the form and substance thereof, which consent shall not be unreasonably withheld
except to the extent such disclosure is required by law or by stock exchange
regulation, provided that (i) any such required disclosure shall only be made,
to the extent consistent with the law, after consultation with such Person and
(ii) no such announcement or disclosure (except as required by law or by stock
exchange regulation) shall identify any such Person without such Person's prior
consent.

                                     * * *


                                       24
<PAGE>

      IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the date first above written.

                                            iBEAM BROADCASTING CORPORATION

                                            By:/s/ Peter Desnoes
                                               -----------------
                                            Name: Peter Desnoes
                                            Title: CEO


                                            WILLIAMS COMMUNICATIONS, LLC

                                            By: /s/ John C. Bumgarner
                                                ---------------------
                                            Name: John C. Bumgarner
                                            Title: Senior Vice President

                   OTHER STOCKHOLDERS SIGNATURE PAGES FOLLOW

<PAGE>

            By execution of this signature page, the undersigned shall become an
Other Stockholder under, and a party to, the Stockholders Agreement, dated as of
July 10, 2001 by and among iBeam Communications Corporation, Williams
Communications, LLC and the Other Stockholders.

Notice:                             ALLEN & COMPANY INCORPORATED
Allen & Company Incorporated
711 5th Avenue - 9th Floor
New York, New York                  By: /s/ Paul A. Gould
Fax: (212) 832-8023                     -----------------
Attn: Paul Gould                    Name: Paul A. Gould
                                    Title: Managing Director


<PAGE>

            By execution of this signature page, the undersigned shall become an
Other Stockholder under, and a party to, the Stockholders Agreement, dated as of
July 10, 2001 by and among iBeam Communications Corporation, Williams
Communications, LLC and the Other Stockholders.

Notice:                             LUNN iBEAM, LLC
Lunn iBeam, LLC
One North Franklin
Suite 750                           By: /s/ Robert Lunn
Chicago, Illinois  60606                ---------------
Fax: (312) 629-2622                 Name: Robert Lunn
                                    Title: Managing Member

<PAGE>

            By execution of this signature page, the undersigned shall become an
Other Stockholder under, and a party to, the Stockholders Agreement, dated as of
July 10, 2001 by and among iBeam Communications Corporation, Williams
Communications, LLC and the Other Stockholders.

Notice:                             TOUCH AMERICA, INC.
Touch America, Inc.
130 North Main Street
Butte, MT 59701-9394                By: /s/ Michael E. Zimmerman
Fax: (406) 497-5240                     ------------------------
Attn: General Counsel               Name: Michael E. Zimmerman
                                    Title: VP Corporate Development