Document:

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                                                                     Exhibit 4.1

                              ESCENE NETWORKS, INC.

                            2000 STOCK INCENTIVE PLAN

        1. Purposes of the Plan. The purposes of this Stock Incentive Plan are
to attract and retain the best available personnel, to provide additional
incentive to Employees, Directors and Consultants and to promote the success of
the Company's business.

        2. Definitions. As used herein, the following definitions shall apply:

               (a) "Administrator" means the Board or any of the Committees
appointed to administer the Plan.

               (b) "Applicable Laws" means the legal requirements relating to
the administration of stock incentive plans, if any, under applicable provisions
of federal and state securities laws, the corporate laws of California and, to
the extent other than California, the corporate law of the state of the
Company's incorporation, the Code, the rules of any applicable stock exchange or
national market system, and the rules of any foreign jurisdiction applicable to
Awards granted to residents therein.

               (c) "Award" means the grant of an Option, Restricted Stock, or
other right or benefit under the Plan.

               (d) "Award Agreement" means the written agreement evidencing the
grant of an Award executed by the Company and the Grantee, including any
amendments thereto.

               (e) "Board" means the Board of Directors of the Company.

               (f) "Code" means the Internal Revenue Code of 1986, as amended.

               (g) "Committee" means any committee appointed by the Board to
administer the Plan.

               (h) "Common Stock" means the common stock of the Company.

               (i) "Company" means eSCENE Networks, Inc., a Delaware
corporation.

               (j) "Consultant" means any person (other than an Employee or a
Director, solely with respect to rendering services in such person's capacity as
a Director) who is engaged by the Company or any Related Entity to render
consulting or advisory services to the Company or such Related Entity.

               (k) "Continuous Service" means that the provision of services to
the Company or a Related Entity in any capacity of Employee, Director or
Consultant, is not interrupted or terminated. Continuous Service shall not be
considered interrupted in the case of (i) any

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approved leave of absence, (ii) transfers among the Company, any Related Entity,
or any successor, in any capacity of Employee, Director or Consultant, or (iii)
any change in status as long as the individual remains in the service of the
Company or a Related Entity in any capacity of Employee, Director or Consultant
(except as otherwise provided in the Award Agreement). An approved leave of
absence shall include sick leave, military leave, or any other authorized
personal leave. For purposes of each Incentive Stock Option granted under the
Plan, if such leave exceeds ninety (90) days, and reemployment upon expiration
of such leave is not guaranteed by statute or contract, then the Incentive Stock
Option shall be treated as a Non-Qualified Stock Option on the day three (3)
months and one (1) day following the expiration of such ninety (90) day period.

               (l) "Corporate Transaction" means any of the following
transactions to which the Company is a party:

                      (i) a merger or consolidation in which the Company is not
the surviving entity, except for a transaction the principal purpose of which is
to change the state in which the Company is incorporated;

                      (ii) the sale, transfer or other disposition of all or
substantially all of the assets of the Company (including the capital stock of
the Company's subsidiary corporations);

                      (iii) approval by the Company's shareholders of any plan
or proposal for the complete liquidation or dissolution of the Company;

                      (iv) any reverse merger in which the Company is the
surviving entity but in which securities possessing more than fifty percent
(50%) of the total combined voting power of the Company's outstanding securities
are transferred to a person or persons different from those who held such
securities immediately prior to such merger; or

                      (v) acquisition by any person or related group of persons
(other than the Company or by a Company-sponsored employee benefit plan) of
beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) of
securities possessing more than fifty percent (50%) of the total combined voting
power of the Company's outstanding securities, but excluding any such
transaction that the Administrator determines shall not be a Corporate
Transaction.

               (m) "Director" means a member of the Board or the board of
directors of any Related Entity.

               (n) "Disability" means a Grantee would qualify for benefit
payments under the long-term disability policy of the Company or the Related
Entity to which the Grantee provides services regardless of whether the Grantee
is covered by such policy. If the Company or the Related Entity to which the
Grantee provides service does not have a long-term disability plan in place,
"Disability" means that a Grantee is permanently unable to carry out the
responsibilities and functions of the position held by the Grantee by reason of
any medically determinable physical or mental impairment. A Grantee will not be
considered to have incurred

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a Disability unless he or she furnishes proof of such impairment sufficient to
satisfy the Administrator in its discretion.

               (o) "Employee" means any person, including an Officer or
Director, who is an employee of the Company or any Related Entity. The payment
of a director's fee by the Company or a Related Entity shall not be sufficient
to constitute "employment" by the Company.

               (p) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

               (q) "Fair Market Value" means, as of any date, the value of
Common Stock determined as follows:

                      (i) Where there exists a public market for the Common
Stock, the Fair Market Value shall be (A) the closing price for a Share for the
last market trading day prior to the time of the determination (or, if no
closing price was reported on that date, on the last trading date on which a
closing price was reported) on the stock exchange determined by the
Administrator to be the primary market for the Common Stock or the Nasdaq
National Market, whichever is applicable or (B) if the Common Stock is not
traded on any such exchange or national market system, the average of the
closing bid and asked prices of a Share on the Nasdaq Small Cap Market for the
day prior to the time of the determination (or, if no such prices were reported
on that date, on the last date on which such prices were reported), in each
case, as reported in The Wall Street Journal or such other source as the
Administrator deems reliable; or

                      (ii) In the absence of an established market for the
Common Stock of the type described in (i), above, the Fair Market Value thereof
shall be determined by the Administrator in good faith and in a manner
consistent with Section 260.140.50 of Title 10 of the California Code of
Regulations.

               (r) "Grantee" means an Employee, Director or Consultant who
receives an Award under the Plan.

               (s) "Incentive Stock Option" means an Option intended to qualify
as an incentive stock option within the meaning of Section 422 of the Code.

               (t) "Non-Qualified Stock Option" means an Option not intended to
qualify as an Incentive Stock Option.

               (u) "Officer" means a person who is an officer of the Company or
a Related Entity within the meaning of Section 16 of the Exchange Act and the
rules and regulations promulgated thereunder.

               (v) "Option" means an option to purchase Shares pursuant to an
Award Agreement granted under the Plan.

               (w) "Parent" means a "parent corporation," whether now or
hereafter existing, as defined in Section 424(e) of the Code.

               (x) "Plan" means this 2000 Stock Incentive Plan .

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               (y) "Post-Termination Exercise Period" means the period specified
in the Award Agreement of not less than three (3) months commencing on the date
of termination of the Grantee's Continuous Service, or such longer period as may
be applicable upon death or Disability.

               (z) "Registration Date" means the first to occur of (i) the
closing of the first sale to the general public of (A) the Common Stock or (B)
the same class of securities of a successor corporation (or its Parent) issued
pursuant to a Corporate Transaction in exchange for or in substitution of the
Common Stock, pursuant to a registration statement filed with and declared
effective by the Securities and Exchange Commission under the Securities Act of
1933, as amended; and (ii) in the event of a Corporate Transaction, the date of
the consummation of the Corporate Transaction if the same class of securities of
the successor corporation (or its Parent) issuable in such Corporate Transaction
shall have been sold to the general public pursuant to a registration statement
filed with and declared effective by the Securities and Exchange Commission
under the Securities Act of 1933, as amended, on or prior to the date of
consummation of such Corporate Transaction.

               (aa) "Related Entity" means any Parent, Subsidiary and any
business, corporation, partnership, limited liability company or other entity in
which the Company, a Parent or a Subsidiary holds a substantial ownership
interest, directly or indirectly.

               (bb) "Restricted Stock" means Shares issued under the Plan to the
Grantee for such consideration, if any, and subject to such restrictions on
transfer, rights of first refusal, repurchase provisions, forfeiture provisions,
and other terms and conditions as established by the Administrator.

               (cc) "Share" means a share of the Common Stock.

               (dd) "Subsidiary" means a "subsidiary corporation," whether now
or hereafter existing, as defined in Section 424(f) of the Code.

        3. Stock Subject to the Plan.

               (a) Subject to the provisions of Section 11(a) below, the maximum
aggregate number of Shares which may be issued pursuant to all Awards (including
Incentive Stock Options) is 4,400,000 Shares. The Shares may be authorized, but
unissued, or reacquired Common Stock.

               (b) Any Shares covered by an Award (or portion of an Award) which
is forfeited or canceled, expires or is settled in cash, shall be deemed not to
have been issued for purposes of determining the maximum aggregate number of
Shares which may be issued under the Plan. Shares that actually have been issued
under the Plan pursuant to an Award shall not be returned to the Plan and shall
not become available for future issuance under the Plan, except that if unvested
Shares are forfeited, or repurchased by the Company at their original purchase
price, such Shares shall become available for future grant under the Plan.

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        4. Administration of the Plan.

               (a) Plan Administrator. With respect to grants of Awards to
Employees, Directors, or Consultants, the Plan shall be administered by (A) the
Board or (B) a Committee (or a subcommittee of the Committee) designated by the
Board, which Committee shall be constituted in such a manner as to satisfy
Applicable Laws. Once appointed, such Committee shall continue to serve in its
designated capacity until otherwise directed by the Board. The Board may
authorize one or more Officers to grant Awards subject to such limitations as
the Board determines from time to time.

               (b) Multiple Administrative Bodies. The Plan may be administered
by different bodies with respect to Directors, Officers, Consultants, and
Employees who are neither Directors nor Officers.

               (c) Powers of the Administrator. Subject to Applicable Laws and
the provisions of the Plan (including any other powers given to the
Administrator hereunder), and except as otherwise provided by the Board, the
Administrator shall have the authority, in its discretion:

                      (i) to select the Employees, Directors and Consultants to
whom Awards may be granted from time to time hereunder;

                      (ii) to determine whether and to what extent Awards are
granted hereunder;

                      (iii) to determine the number of Shares or the amount of
other consideration to be covered by each Award granted hereunder;

                      (iv) to approve forms of Award Agreements for use under
the Plan;

                      (v) to determine the terms and conditions of any Award
granted hereunder;

                      (vi) to establish additional terms, conditions, rules or
procedures to accommodate the rules or laws of applicable foreign jurisdictions
and to afford Grantees favorable treatment under such rules or laws; provided,
however, that no Award shall be granted under any such additional terms,
conditions, rules or procedures with terms or conditions which are inconsistent
with the provisions of the Plan;

                      (vii) to amend the terms of any outstanding Award granted
under the Plan, provided that any amendment that would adversely affect the
Grantee's rights under an outstanding Award shall not be made without the
Grantee's written consent;

                      (viii) to construe and interpret the terms of the Plan and
Awards, including without limitation, any notice of award or Award Agreement,
granted pursuant to THE Plan; and

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                      (ix) to take such other action, not inconsistent with the
terms of the Plan, as the Administrator deems appropriate.

        5. Eligibility. Awards other than Incentive Stock Options may be granted
to Employees, Directors and Consultants. Incentive Stock Options may be granted
only to Employees of the Company, a Parent or a Subsidiary. An Employee,
Director or Consultant who has been granted an Award may, if otherwise eligible,
be granted additional Awards. Awards may be granted to such Employees, Directors
or Consultants who are residing in foreign jurisdictions as the Administrator
may determine from time to time.

        6. Terms and Conditions of Awards.

               (a) Type of Awards. The Administrator is authorized under the
Plan to award any type of arrangement to an Employee, Director or Consultant
that is not inconsistent with the provisions of the Plan and that by its terms
involves or might involve the issuance of (i) Shares, (ii) an Option, or similar
right with a fixed or variable price related to the Fair Market Value of the
Shares and with an exercise or conversion privilege related to the passage of
time, the occurrence of one or more events, or the satisfaction of performance
criteria or other conditions, or (iii) any other security with the value derived
from the value of the Shares. Such awards include, without limitation, Options,
or sales or bonuses of Restricted Stock, and an Award may consist of one such
security or benefit, or two (2) or more of them in any combination or
alternative.

               (b) Designation of Award. Each Award shall be designated in the
Award Agreement. In the case of an Option, the Option shall be designated as
either an Incentive Stock Option or a Non-Qualified Stock Option. However,
notwithstanding such designation, to the extent that the aggregate Fair Market
Value of Shares subject to Options designated as Incentive Stock Options which
become exercisable for the first time by a Grantee during any calendar year
(under all plans of the Company or any Parent or Subsidiary) exceeds $100,000,
such excess Options, to the extent of the Shares covered thereby in excess of
the foregoing limitation, shall be treated as Non-Qualified Stock Options. For
this purpose, Incentive Stock Options shall be taken into account in the order
in which they were granted, and the Fair Market Value of the Shares shall be
determined as of the grant date of the relevant Option.

               (c) Conditions of Award. Subject to the terms of the Plan, the
Administrator shall determine the provisions, terms, and conditions of each
Award including, but not limited to, the Award vesting schedule, repurchase
provisions, rights of first refusal, forfeiture provisions, form of payment
(cash, Shares, or other consideration) upon settlement of the Award, payment
contingencies, and satisfaction of any performance criteria. The performance
criteria established by the Administrator may be based on any one of, or
combination of, increase in share price, earnings per share, total shareholder
return, return on equity, return on assets, return on investment, net operating
income, cash flow, revenue, economic value added, personal management
objectives, or other measure of performance selected by the Administrator.
Partial achievement of the specified criteria may result in a payment or vesting
corresponding to the degree of achievement as specified in the Award Agreement.

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               (d) Acquisitions and Other Transactions. The Administrator may
issue Awards under the Plan in settlement, assumption or substitution for,
outstanding awards or obligations to grant future awards in connection with the
Company or a Related Entity acquiring another entity, an interest in another
entity or an additional interest in a Related Entity whether by merger, stock
purchase, asset purchase or other form of transaction.

               (e) Deferral of Award Payment. The Administrator may establish
one or more programs under the Plan to permit selected Grantees the opportunity
to elect to defer receipt of consideration upon exercise of an Award,
satisfaction of performance criteria, or other event that absent the election
would entitle the Grantee to payment or receipt of Shares or other consideration
under an Award. The Administrator may establish the election procedures, the
timing of such elections, the mechanisms for payments of, and accrual of
interest or other earnings, if any, on amounts, Shares or other consideration so
deferred, and such other terms, conditions, rules and procedures that the
Administrator deems advisable for the administration of any such deferral
program.

               (f) Award Exchange Programs. The Administrator may establish one
or more programs under the Plan to permit selected Grantees to exchange an Award
under the Plan for one or more other types of Awards under the Plan on such
terms and conditions as determined by the Administrator from time to time.

               (g) Separate Programs. The Administrator may establish one or
more separate programs under the Plan for the purpose of issuing particular
forms of Awards to one or more classes of Grantees on such terms and conditions
as determined by the Administrator from time to time.

               (h) Early Exercise. The Award Agreement may, but need not,
include a provision whereby the Grantee may elect at any time while an Employee,
Director or Consultant to exercise any part or all of the Award prior to full
vesting of the Award. Any unvested Shares received pursuant to such exercise may
be subject to a repurchase right in favor of the Company or a Related Entity or
to any other restriction the Administrator determines to be appropriate.

               (i) Term of Award. The term of each Award shall be the term
stated in the Award Agreement, provided, however, that the term shall be no more
than ten (10) years from the date of grant thereof. However, in the case of an
Incentive Stock Option granted to a Grantee who, at the time the Option is
granted, owns stock representing more than ten percent (10%) of the voting power
of all classes of stock of the Company or any Parent or Subsidiary, the term of
the Incentive Stock Option shall be five (5) years from the date of grant
thereof or such shorter term as may be provided in the Award Agreement.

               (j) Transferability of Awards. Non-Qualified Stock Options shall
be transferable (i) to the extent provided in the Award Agreement and in a
manner consistent with Section 260.140.41 of Title 10 of the California Code of
Regulations and (ii) by will, and by the laws of descent and distribution.
Incentive Stock Options and other Awards may not be sold, pledged, assigned,
hypothecated, transferred, or disposed of in any manner other than by will or by
the laws of descent or distribution and may be exercised, during the lifetime of
the Grantee, only by the Grantee.

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               (k) Time of Granting Awards. The date of grant of an Award shall
for all purposes be the date on which the Administrator makes the determination
to grant such Award, or such other date as is determined by the Administrator.
Notice of the grant determination shall be given to each Employee, Director or
Consultant to whom an Award is so granted within a reasonable time after the
date of such grant.

        7. Award Exercise or Purchase Price, Consideration and Taxes.

               (a) Exercise or Purchase Price. The exercise or purchase price,
if any, for an Award shall be as follows:

                      (i) In the case of an Incentive Stock Option:

                             (A) granted to an Employee who, at the time of the
grant of such Incentive Stock Option owns stock representing more than ten
percent (10%) of the voting power of all classes of stock of the Company or any
Parent or Subsidiary, the per Share exercise price shall be not less than one
hundred ten percent (110%) of the Fair Market Value per Share on the date of
grant; or

                             (B) granted to any Employee other than an Employee
described in the preceding paragraph, the per Share exercise price shall be not
less than one hundred percent (100%) of the Fair Market Value per Share on the
date of grant.

                      (ii) In the case of a Non-Qualified Stock Option:

                             (A) granted to a person who, at the time of the
grant of such Option, owns stock representing more than ten percent (10%) of the
voting power of all classes of stock of the Company or any Parent or Subsidiary,
the per Share exercise price shall be not less than one hundred ten percent
(110%) of the Fair Market Value per Share on the date of grant; or

                             (B) granted to any person other than a person
described in the preceding paragraph, the per Share exercise price shall be not
less than eighty-five percent (85%) of the Fair Market Value per Share on the
date of grant.

                      (iii) In the case of the sale of Shares:

                             (A) granted to a person who, at the time of the
grant of such Award, or at the time the purchase is consummated, owns stock
representing more than ten percent (10%) of the voting power of all classes of
stock of the Company or any Parent or Subsidiary, the per Share purchase price
shall be not less than one hundred percent (100%) of the Fair Market Value per
Share on the date of grant; or

                             (B) granted to any person other than a person
described in the preceding paragraph, the per Share purchase price shall be not
less than eighty-five percent (85%) of the Fair Market Value per Share on the
date of grant.

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                      (iv) In the case of other Awards, such price as is
determined by the Administrator.

                      (v) Notwithstanding the foregoing provisions of this
Section 7(a), in the case of an Award issued pursuant to Section 6(d), above,
the exercise or purchase price for the Award shall be determined in accordance
with the principles of Section 424(a) of the Code.

               (b) Consideration. Subject to Applicable Laws, the consideration
to be paid for the Shares to be issued upon exercise or purchase of an Award
including the method of payment, shall be determined by the Administrator (and,
in the case of an Incentive Stock Option, shall be determined at the time of
grant). In addition to any other types of consideration the Administrator may
determine, the Administrator is authorized to accept as consideration for Shares
issued under the Plan the following:

                      (i) cash;

                      (ii) check;

                      (iii) delivery of Grantee's promissory note with such
recourse, interest, security, and redemption provisions as the Administrator
determines as appropriate;

                      (iv) if the exercise or purchase occurs on or after the
Registration Date, surrender of Shares or delivery of a properly executed form
of attestation of ownership of Shares as the Administrator may require
(including withholding of Shares otherwise deliverable upon exercise of the
Award) which have a Fair Market Value on the date of surrender or attestation
equal to the aggregate exercise price of the Shares as to which said Award shall
be exercised (but only to the extent that such exercise of the Award would not
result in an accounting compensation charge with respect to the Shares used to
pay the exercise price unless otherwise determined by the Administrator);

                      (v) with respect to Options, if the exercise occurs on or
after the Registration Date, payment through a broker-dealer sale and remittance
procedure pursuant to which the Grantee (A) shall provide written instructions
to a Company designated brokerage firm to effect the immediate sale of some or
all of the purchased Shares and remit to the Company, out of the sale proceeds
available on the settlement date, sufficient funds to cover the aggregate
exercise price payable for the purchased Shares and (B) shall provide written
directives to the Company to deliver the certificates for the purchased Shares
directly to such brokerage firm in order to complete the sale transaction; or

                      (vi) any combination of the foregoing methods of payment.

               (c) Taxes. No Shares shall be delivered under the Plan to any
Grantee or other person until such Grantee or other person has made arrangements
acceptable to the Administrator for the satisfaction of any foreign, federal,
state, or local income and employment tax withholding obligations, including,
without limitation, obligations incident to the receipt of Shares or the
disqualifying disposition of Shares received on exercise of an Incentive Stock
Option. Upon exercise of an Award the Company shall withhold or collect from
Grantee an amount sufficient to satisfy such tax obligations.

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        8. Exercise of Award.

               (a) Procedure for Exercise; Rights as a Shareholder.

                      (i) Any Award granted hereunder shall be exercisable at
such times and under such conditions as determined by the Administrator under
the terms of the Plan and specified in the Award Agreement but in the case of an
Option, in no case at a rate of less than twenty percent (20%) per year over
five (5) years from the date the Option is granted, subject to reasonable
conditions such as continued employment. Notwithstanding the foregoing, in the
case of an Option granted to an Officer, Director or Consultant, the Award
Agreement may provide that the Option may become exercisable, subject to
reasonable conditions such as such Officer's, Director's or Consultant's
Continuous Service, at any time or during any period established in the Award
Agreement.

                      (ii) An Award shall be deemed to be exercised when written
notice of such exercise has been given to the Company in accordance with the
terms of the Award by the person entitled to exercise the Award and full payment
for the Shares with respect to which the Award is exercised, including, to the
extent selected, use of the broker-dealer sale and remittance procedure to pay
the purchase price as provided in Section 7(b)(v). Until the issuance (as
evidenced by the appropriate entry on the books of the Company or of a duly
authorized transfer agent of the Company) of the stock certificate evidencing
such Shares, no right to vote or receive dividends or any other rights as a
shareholder shall exist with respect to Shares subject to an Award,
notwithstanding the exercise of an Option or other Award. No adjustment will be
made for a dividend or other right for which the record date is prior to the
date the stock certificate is issued, except as provided in the Award Agreement
or Section 11(a), below.

               (b) Exercise of Award Following Termination of Continuous
Service. In the event of termination of a Grantee's Continuous Service for any
reason other than Disability or death (but not in the event of a Grantee's
change of status from Employee to Consultant or from Consultant to Employee),
such Grantee may, but only during the Post-Termination Exercise Period (but in
no event later than the expiration date of the term of such Award as set forth
in the Award Agreement), exercise the Award to the extent that the Grantee was
entitled to exercise it at the date of such termination or to such other extent
as may be determined by the Administrator In the event of a Grantee's change of
status from Employee to Consultant, an Employee's Incentive Stock Option shall
convert automatically to a Non-Qualified Stock Option on the day three (3)
months and one day following such change of status. To the extent that the
Grantee is not entitled to exercise the Award at the date of termination, or if
the Grantee does not exercise such Award to the extent so entitled within the
Post-Termination Exercise Period, the Award shall terminate.

               (c) Disability of Grantee. In the event of termination of a
Grantee's Continuous Service as a result of his or her Disability, Grantee may,
but only within six (6) months from the date of such termination (and in no
event later than the expiration date of the term of such Award as set forth in
the Award Agreement), exercise the Award to the extent that the Grantee was
otherwise entitled to exercise it at the date of such termination; provided,
however, that if such Disability is not a "disability" as such term is defined
in Section 22(e)(3) of the Code, in the case of an Incentive Stock Option such
Incentive Stock Option shall

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automatically convert to a Non-Qualified Stock Option on the day three (3)
months and one day following such termination. To the extent that the Grantee is
not entitled to exercise the Award at the date of termination, or if Grantee
does not exercise such Award to the extent so entitled within the time specified
herein, the Award shall terminate.

               (d) Death of Grantee. In the event of a termination of the
Grantee's Continuous Service as a result of his or her death, or in the event of
the death of the Grantee during the Post-Termination Exercise Period or during
the twelve (12) month period following the Grantee's termination of Continuous
Service as a result of his or her Disability, the Grantee's estate or a person
who acquired the right to exercise the Award by bequest or inheritance may
exercise the Award, but only to the extent that the Grantee was entitled to
exercise the Award as of the date of termination, within twelve (12) months from
the date of death (but in no event later than the expiration of the term of such
Award as set forth in the Award Agreement). To the extent that, at the time of
death, the Grantee was not entitled to exercise the Award, or if the Grantee's
estate or a person who acquired the right to exercise the Award by bequest or
inheritance does not exercise such Award to the extent so entitled within the
time specified herein, the Award shall terminate.

        9. Conditions Upon Issuance of Shares.

               (a) Shares shall not be issued pursuant to the exercise of an
Award unless the exercise of such Award and the issuance and delivery of such
Shares pursuant thereto shall comply with all Applicable Laws, and shall be
further subject to the approval of counsel for the Company with respect to such
compliance.

               (b) As a condition to the exercise of an Award, the Company may
require the person exercising such Award to represent and warrant at the time of
any such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares if, in the
opinion of counsel for the Company, such a representation is required by any
Applicable Laws.

        10. Repurchase Rights. If the provisions of an Award Agreement grant to
the Company the right to repurchase Shares upon termination of the Grantee's
Continuous Service, the Award Agreement shall (or may, with respect to Awards
granted or issued to Officers, Directors or Consultants) provide that:

               (a) the right to repurchase must be exercised, if at all, within
ninety (90) days of the termination of the Grantee's Continuous Service (or in
the case of Shares issued upon exercise of Awards after the date of termination
of the Grantee's Continuous Service, within ninety (90) days after the date of
the Award exercise);

               (b) the consideration payable for the Shares upon exercise of
such repurchase right shall be made in cash or by cancellation of purchase money
indebtedness within the ninety (90) day periods specified in Section 10(a);

               (c) the amount of such consideration shall (i) be equal to the
original purchase price paid by Grantee for each such Share; provided, that the
right to repurchase such Shares at the original purchase price shall lapse at
the rate of at least twenty percent (20%) of the Shares

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subject to the Award per year over five (5) years from the date the Award is
granted (without respect to the date the Award was exercised or became
exercisable), and (ii) with respect to Shares, other than Shares subject to
repurchase at the original purchase price pursuant to clause (i) above, not less
than the Fair Market Value of the Shares to be repurchased on the date of
termination of Grantee's Continuous Service; and

               (d) the right to repurchase Shares, other than the right to
repurchase Shares at the original purchase price pursuant to clause (i) of
Section 10(c), shall terminate on the Registration Date.

        11. Adjustments Upon Changes in Capitalization or Corporate Transaction.

               (a) Adjustments upon Changes in Capitalization. Subject to any
required action by the shareholders of the Company, the number of Shares covered
by each outstanding Award, and the number of Shares which have been authorized
for issuance under the Plan but as to which no Awards have yet been granted or
which have been returned to the Plan, the exercise or purchase price of each
such outstanding Award, as well as any other terms that the Administrator
determines require adjustment shall be proportionately adjusted for (i) any
increase or decrease in the number of issued Shares resulting from a stock
split, reverse stock split, stock dividend, combination or reclassification of
the Shares, or similar transaction affecting the Shares, (ii) any other increase
or decrease in the number of issued Shares effected without receipt of
consideration by the Company, or (iii) as the Administrator may determine in its
discretion, any other transaction with respect to Common Stock to which Section
424(a) of the Code applies or a similar transaction; provided, however that
conversion of any convertible securities of the Company shall not be deemed to
have been "effected without receipt of consideration." Such adjustment shall be
made by the Administrator and its determination shall be final, binding and
conclusive. Except as the Administrator determines, no issuance by the Company
of shares of stock of any class, or securities convertible into shares of stock
of any class, shall affect, and no adjustment by reason hereof shall be made
with respect to, the number or price of Shares subject to an Award.

               (b) Corporate Transaction.

                      Termination of Award if Not Assumed. In the event of a
Corporate Transaction, each Award will terminate upon the consummation of the
Corporate Transaction, unless the Award is assumed by the successor corporation
or Parent thereof in connection with the Corporate Transaction.

                      Acceleration of Award Upon Corporate Transaction. Except
as provided otherwise in an individual Award Agreement, in the event of any
Corporate Transaction, there will not be any acceleration of vesting or
exercisability of any Award.

        12. Effective Date and Term of Plan. The Plan shall become effective
upon the earlier to occur of its adoption by the Board or its approval by the
shareholders of the Company. It shall continue in effect for a term of ten (10)
years unless sooner terminated. Subject to Section 17, below, and Applicable
Laws, Awards may be granted under the Plan upon its becoming effective.

                                      -12-
<PAGE>   13

        13. Amendment, Suspension or Termination of the Plan.

               (a) The Board may at any time amend, suspend or terminate the
Plan. To the extent necessary to comply with Applicable Laws, the Company shall
obtain shareholder approval of any Plan amendment in such a manner and to such a
degree as required.

               (b) No Award may be granted during any suspension of the Plan or
after termination of the Plan.

               (c) Any amendment, suspension or termination of the Plan
(including termination of the Plan under Section 12, above) shall not affect
Awards already granted, and such Awards shall remain in full force and effect as
if the Plan had not been amended, suspended or terminated, unless mutually
agreed otherwise between the Grantee and the Administrator, which agreement must
be in writing and signed by the Grantee and the Company.

        14. Reservation of Shares.

               (a) The Company, during the term of the Plan, will at all times
reserve and keep available such number of Shares as shall be sufficient to
satisfy the requirements of the Plan.

               (b) The inability of the Company to obtain authority from any
regulatory body having jurisdiction, which authority is deemed by the Company's
counsel to be necessary to the lawful issuance and sale of any Shares hereunder,
shall relieve the Company of any liability in respect of the failure to issue or
sell such Shares as to which such requisite authority shall not have been
obtained.

        15. No Effect on Terms of Employment/Consulting Relationship. The Plan
shall not confer upon any Grantee any right with respect to the Grantee's
Continuous Service, nor shall it interfere in any way with his or her right or
the Company's right to terminate the Grantee's Continuous Service at any time,
and with or without notice.

        16. No Effect on Retirement and Other Benefit Plans. Except as
specifically provided in a retirement or other benefit plan of the Company or a
Related Entity, Awards shall not be deemed compensation for purposes of
computing benefits or contributions under any retirement plan of the Company or
a Related Entity, and shall not affect any benefits under any other benefit plan
of any kind or any benefit plan subsequently instituted under which the
availability or amount of benefits is related to level of compensation. The Plan
is not a "Retirement Plan" or "Welfare Plan" under the Employee Retirement
Income Security Act of 1974, as amended.

        17. Shareholder Approval. Continuance of the Plan shall be subject to
approval by the shareholders of the Company within twelve (12) months before or
after the date the Plan is adopted. Such shareholder approval shall be obtained
in the degree and manner required under Applicable Laws. Any Award exercised
before shareholder approval is obtained shall be rescinded if shareholder
approval is not obtained within the time prescribed, and Shares issued on the
exercise of any such Award shall not be counted in determining whether
shareholder approval is obtained.

                                      -13-
<PAGE>   14

        18. Information to Grantees. The Company shall provide to each Grantee,
during the period for which such Grantee has one or more Awards outstanding,
copies of financial statements at least annually.

                                      -14-
<PAGE>   15

                              ESCENE NETWORKS, INC.

                            2000 STOCK INCENTIVE PLAN

                          NOTICE OF STOCK OPTION AWARD

Grantee's Name and Address:    _________________________________________________

                               _________________________________________________

                               _________________________________________________

        You have been granted an option to purchase shares of Common Stock,
subject to the terms and conditions of this Notice of Stock Option Award (the
"Notice"), the eSCENE Networks, Inc, 2000 Stock Incentive Plan, as amended from
time to time (the "Plan") and the Stock Option Award Agreement (the "Option
Agreement") attached hereto, as follows. Unless otherwise defined herein, the
terms defined in the Plan shall have the same defined meanings in this Notice.

        Award Number                    ________________________________________

        Date of Award                   ________________________________________

        Vesting Commencement Date       ________________________________________

        Exercise Price per Share        $_______________________________________

        Total Number of Shares Subject

        to the Option (the "Shares")    ________________________________________

        Total Exercise Price            $_______________________________________

        Type of Option:                 ___________   Incentive Stock Option

                                        ___________   Non-Qualified Stock Option

        Expiration Date:                ________________________________________

        Post-Termination Exercise Period: Three (3) Months

<PAGE>   16

        Vesting Schedule:

        Subject to Grantee's Continuous Service and other limitations set forth
in this Notice, the Plan and the Option Agreement, the Option may be exercised,
in whole or in part, in accordance with the following schedule:

        16.7% of the Shares subject to the Option shall vest six months after
the Vesting Commencement Date, and 1/36 of the Shares subject to the Option
shall vest on each monthly anniversary of the Vesting Commencement Date
thereafter. In the event of a Corporate Transaction (as defined in the "Plan"),
50% of the remaining unvested Shares subject to the Option shall vest
immediately and the remaining unvested Shares shall vest monthly thereafter.

        During any authorized leave of absence, the vesting of the Option as
provided in this schedule shall cease after the leave of absence exceeds a
period of ninety (90) days Vesting of the Option shall resume upon the Grantee's
termination of the leave of absence and return to service to the Company or a
Related Entity.

        In the event of the Grantee's change in status from Employee to
Consultant or from an Employee whose customary employment is 20 hours or more
per week to an Employee whose customary employment is fewer than 20 hours per
week, vesting of the Option shall continue only to the extent determined by the
Administrator as of such change in status consistent with any minimum vesting
requirements set forth in the Plan.

                                      -2-
<PAGE>   17

        IN WITNESS WHEREOF, the Company and the Grantee have executed this
Notice and agree that the Option is to be governed by the terms and conditions
of this Notice, the Plan, and the Option Agreement.

                                      eSCENE Networks, Inc.,
                                      a Delaware corporation

                                      By: _____________________________________

                                      Title: __________________________________

                                      -3-
<PAGE>   18

        THE GRANTEE ACKNOWLEDGES AND AGREES THAT THE SHARES SUBJECT TO THE
OPTION SHALL VEST, IF AT ALL, ONLY DURING THE PERIOD OF THE GRANTEE'S CONTINUOUS
SERVICE (NOT THROUGH THE ACT OF BEING HIRED, BEING GRANTED THE OPTION OR
ACQUIRING SHARES HEREUNDER). THE GRANTEE FURTHER ACKNOWLEDGES AND AGREES THAT
NOTHING IN THIS NOTICE, THE OPTION AGREEMENT, OR THE PLAN SHALL CONFER UPON THE
GRANTEE ANY RIGHT WITH RESPECT TO FUTURE AWARDS OR CONTINUATION OF GRANTEE'S
CONTINUOUS SERVICE, NOR SHALL IT INTERFERE IN ANY WAY WITH THE GRANTEE'S RIGHT
OR THE RIGHT OF THE GRANTEE'S EMPLOYER TO TERMINATE GRANTEE'S CONTINUOUS
SERVICE, WITH OR WITHOUT CAUSE, AND WITH OR WITHOUT NOTICE. THE GRANTEE
ACKNOWLEDGES THAT UNLESS THE GRANTEE HAS A WRITTEN EMPLOYMENT AGREEMENT WITH THE
COMPANY TO THE CONTRARY, GRANTEE'S STATUS IS AT WILL.

        The Grantee acknowledges receipt of a copy of the Plan and the Option
Agreement, and represents that he or she is familiar with the terms and
provisions thereof, and hereby accepts the Option subject to all of the terms
and provisions hereof and thereof. The Grantee has reviewed this Notice, the
Plan, and the Option Agreement in their entirety, has had an opportunity to
obtain the advice of counsel prior to executing this Notice, and fully
understands all provisions of this Notice, the Plan and the Option Agreement.
The Grantee hereby agrees that all disputes arising out of or relating to this
Notice, the Plan and the Option Agreement shall be resolved in accordance with
Section 19 of the Option Agreement. The Grantee further agrees to notify the
Company upon any change in the residence address indicated in this Notice.

Dated: __________________            Signed: ___________________________________
                                                        Grantee

                                      -4-
<PAGE>   19

                                                       AWARD NUMBER: ___________

                              ESCENE NETWORKS INC.

                            2000 STOCK INCENTIVE PLAN

                          STOCK OPTION AWARD AGREEMENT

        (a) Grant of Option. eSCENE Networks, Inc., a Delaware corporation (the
"Company"), hereby grants to the Grantee (the "Grantee") named in the Notice of
Stock Option Award (the "Notice"), an option (the "Option") to purchase the
Total Number of Shares of Common Stock subject to the Option (the "Shares") set
forth in the Notice, at the Exercise Price per Share set forth in the Notice
(the "Exercise Price") subject to the terms and provisions of the Notice, this
Stock Option Award Agreement (the "Option Agreement") and the Company's 2000
Stock Incentive Plan, as amended from time to time (the "Plan"), which are
incorporated herein by reference. Unless otherwise defined herein, the terms
defined in the Plan shall have the same defined meanings in this Option
Agreement.

        If designated in the Notice as an Incentive Stock Option, the Option is
intended to qualify as an Incentive Stock Option as defined in Section 422 of
the Code. However, notwithstanding such designation, to the extent that the
aggregate Fair Market Value of Shares subject to Options designated as Incentive
Stock Options which become exercisable for the first time by the Grantee during
any calendar year (under all plans of the Company or any Parent or Subsidiary)
exceeds $100,000, such excess Options, to the extent of the Shares covered
thereby in excess of the foregoing limitation, shall be treated as Non-Qualified
Stock Options. For this purpose, Incentive Stock Options shall be taken into
account in the order in which they were granted, and the Fair Market Value of
the Shares shall be determined as of the date the Option with respect to such
Shares is awarded.

        (b) Exercise of Option.

               (i) Right to Exercise. The Option shall be exercisable during its
term in accordance with the Vesting Schedule set out in the Notice and with the
applicable provisions of the Plan and this Option Agreement. The Option shall be
subject to the provisions of Section 11(b) of the Plan relating to the
exercisability or termination of the Option in the event of a Corporate
Transaction. No partial exercise of the Option may be for less than the lesser
of five percent (5%) of the total number of Shares subject to the Option or the
remaining number of Shares subject to the Option. In no event shall the Company
issue fractional Shares.

               (i) Method of Exercise. The Option shall be exercisable only by
delivery of an Exercise Notice (attached as Exhibit A) which shall state the
election to exercise the Option, the whole number of Shares in respect of which
the Option is being exercised, and such other provisions as may be required by
the Administrator. The Exercise Notice shall be signed by the Grantee and shall
be delivered in person, by certified mail, or by such other method as determined
from time to time by the Administrator to the Company accompanied by payment of
the Exercise Price. The Option shall be deemed to be exercised upon receipt by
the Company of such written notice accompanied by the Exercise

<PAGE>   20

Price, which, to the extent selected, shall be deemed to be satisfied by use of
the broker-dealer sale and remittance procedure to pay the Exercise Price
provided in Section 4(d), below.

               (ii) Taxes. No Shares will be delivered to the Grantee or other
person pursuant to the exercise of the Option until the Grantee or other person
has made arrangements acceptable to the Administrator for the satisfaction of
applicable income tax, employment tax, and social security tax withholding
obligations, including, without limitation, obligations incident to the receipt
of Shares or the disqualifying disposition of Shares received on exercise of an
Incentive Stock Option. Upon exercise of the Option, the Company or the
Grantee's employer may offset or withhold (from any amount owed by the Company
or the Grantee's employer to the Grantee) or collect from the Grantee or other
person an amount sufficient to satisfy such tax obligations and/or the
employer's withholding obligations.

        (c) Grantee's Representations. The Grantee understands that neither the
Option nor the Shares exercisable pursuant to the Option have been registered
under the Securities Act of 1933, as amended or any United States securities
laws. In the event the Shares purchasable pursuant to the exercise of the Option
have not been registered under the Securities Act of 1933, as amended, at the
time the Option is exercised, the Grantee shall, if requested by the Company,
concurrently with the exercise of all or any portion of the Option, deliver to
the Company his or her Investment Representation Statement in the form attached
hereto as Exhibit B.

        (d) Method of Payment. Payment of the Exercise Price shall be made by
any of the following, or a combination thereof, at the election of the Grantee;
provided, however, that such exercise method does not then violate any
Applicable Law and, provided further, that the portion of the Exercise Price
equal to the par value of the Shares must be paid in cash or other legal
consideration permitted by the Delaware General Corporation Law:

               (i) cash;

               (ii) check;

               (iii) if the exercise occurs on or after the Registration Date,
surrender of Shares or delivery of a properly executed form of attestation of
ownership of Shares as the Administrator may require (including withholding of
Shares otherwise deliverable upon exercise of the Option) which have a Fair
Market Value on the date of surrender or attestation equal to the aggregate
Exercise Price of the Shares as to which the Option is being exercised (but only
to the extent that such exercise of the Option would not result in an accounting
compensation charge with respect to the Shares used to pay the exercise price);
or

               (iv) if the exercise occurs on or after the Registration Date,
payment through a broker-dealer sale and remittance procedure pursuant to which
the Grantee (i) shall provide written instructions to a Company designated
brokerage firm to effect the immediate sale of some or all of the purchased
Shares and remit to the Company, out of the sale proceeds available on the
settlement date, sufficient funds to cover the aggregate exercise price payable
for the purchased Shares and (ii) shall provide written directives to the
Company to deliver the certificates for the purchased Shares directly to such
brokerage firm in order to complete the sale transaction.

        (e) Restrictions on Exercise. The Option may not be exercised if the
issuance of the Shares subject to the Option upon such exercise would constitute
a violation of any Applicable Laws. In addition, the Option may not be exercised
until such time as the Plan has been approved by the stockholders of the
Company.

                                      -2-
<PAGE>   21

        (f) Termination or Change of Continuous Service. In the event the
Grantee's Continuous Service terminates, the Grantee may, to the extent
otherwise so entitled at the date of such termination (the "Termination Date"),
exercise the Option during the Post-Termination Exercise Period. In no event
shall the Option be exercised later than the Expiration Date set forth in the
Notice. In the event of the Grantee's change in status from Employee, Director
or Consultant to any other status of Employee, Director or Consultant, the
Option shall remain in effect and, except to the extent otherwise determined by
the Administrator, continue to vest; provided, however, with respect to any
Incentive Stock Option that shall remain in effect after a change in status from
Employee to Director or Consultant, such Incentive Stock Option shall cease to
be treated as an Incentive Stock Option and shall be treated as a Non-Qualified
Stock Option on the day three (3) months and one (1) day following such change
in status. Except as provided in Sections 7 and 8 below, to the extent that the
Grantee is not entitled to exercise the Option on the Termination Date, or if
the Grantee does not exercise the Option within the Post-Termination Exercise
Period, the Option shall terminate.

        8. Disability of Grantee. In the event the Grantee's Continuous Service
terminates as a result of his or her Disability, the Grantee may, but only
within six (6) months from the Termination Date (and in no event later than the
Expiration Date), exercise the Option to the extent he or she was otherwise
entitled to exercise it on the Termination Date; provided, however, that if such
Disability is not a "disability" as such term is defined in Section 22(e)(3) of
the Code and the Option is an Incentive Stock Option, such Incentive Stock
Option shall cease to be treated as an Incentive Stock Option and shall be
treated as a Non-Qualified Stock Option on the day three (3) months and one (1)
day following the Termination Date. To the extent that the Grantee is not
entitled to exercise the Option on the Termination Date, or if the Grantee does
not exercise the Option to the extent so entitled within the time specified
herein, the Option shall terminate.

        (g) Death of Grantee. In the event of the termination of the Grantee's
Continuous Service as a result of his or her death, or in the event of the
Grantee's death during the Post-Termination Exercise Period or during the twelve
(12) month period following the Grantee's termination of Continuous Service as a
result of his or her Disability, the Grantee's estate, or a person who acquired
the right to exercise the Option by bequest or inheritance, may exercise the
Option, but only to the extent the Grantee could exercise the Option at the date
of termination, within twelve (12) months from the date of death (but in no
event later than the Expiration Date). To the extent that the Grantee is not
entitled to exercise the Option on the date of death, or if the Option is not
exercised to the extent so entitled within the time specified herein, the Option
shall terminate.

        (h) Transferability of Option. The Option, if an Incentive Stock Option,
may not be transferred in any manner other than by will or by the laws of
descent and distribution and may be exercised during the lifetime of the Grantee
only by the Grantee. The Option, if a Non-Qualified Stock Option may be
transferred by will, by the laws of descent and distribution, and to the extent
and in the manner authorized by the Administrator, to members of the Grantee's
immediate family (as determined by the Administrator) or pursuant to a domestic
relations order. The terms of the Option shall be binding upon the executors,
administrators, heirs and successors of the Grantee.

        (i) Term of Option. The Option may be exercised no later than the
Expiration Date set forth in the Notice or such earlier date as otherwise
provided herein.

        (j) Company's Right of First Refusal.

               (i) Transfer Notice. Neither the Grantee nor a transferee (either
being sometimes referred to herein as the "Holder") shall sell, hypothecate,
encumber or otherwise transfer any Shares or any right or interest therein
without first complying with the provisions of this Section 11 or obtaining the

                                      -3-
<PAGE>   22

prior written consent of the Company. In the event the Holder desires to accept
a bona fide third-party offer for any or all of the Shares, the Holder shall
provide the Company with written notice (the "Transfer Notice") of:

                          (1)    The Holder's intention to transfer;

                          (2)    The name of the proposed transferee;

                          (3)    The number of Shares to be transferred; and

                          (4)    The proposed transfer price or value and terms
thereof.

               (ii) First Refusal Exercise Notice. The Company shall have the
right to purchase (the "Right of First Refusal") all but not less than all, of
the Shares which are described in the Transfer Notice (the "Offered Shares") at
any time during the period commencing upon receipt of the Transfer Notice and
ending forty-five (45) days after the first date on which the Company determines
that the Right of First Refusal may be exercised without incurring an accounting
expense with respect to such exercise (the "Option Period") at the per share
price or value and in accordance with the terms stated in the Transfer Notice,
which Right of First Refusal shall be exercised by written notice (the "First
Refusal Exercise Notice") to the Holder. During the Option Period and the
120-day period following the expiration of the Option Period, the Company also
may exercise its Repurchase Right in lieu or in addition to its Right of First
Refusal if the Repurchase Right is or becomes exercisable during the Option
Period or such 120-day period.

               (iii) Payment Terms. The Company shall consummate the purchase of
the Offered Shares on the terms set forth in the Transfer Notice within 15 days
after delivery of the First Refusal Exercise Notice; provided, however, that in
the event the Transfer Notice provides for the payment for the Offered Shares
other than in cash, the Company and/or its assigns shall have the right to pay
for the Offered Shares by the discounted cash equivalent of the consideration
described in the Transfer Notice as reasonably determined by the Administrator.
Upon payment for the Offered Shares to the Holder or into escrow for the benefit
of the Holder, the Company or its assigns shall become the legal and beneficial
owner of the Offered Shares and all rights and interest therein or related
thereto, and the Company shall have the right to transfer the Offered Shares to
its own name or its assigns without further action by the Holder.

               (ii) Assignment. Whenever the Company shall have the right to
purchase Shares under this Right of First Refusal, the Company may designate and
assign one or more employees, officers, directors or stockholders of the Company
or other persons or organizations, to exercise all or a part of the Company's
Right of First Refusal.

               (iv) Non-Exercise. If the Company and/or its assigns do not
collectively elect to exercise the Right of First Refusal within the Option
Period or such earlier time if the Company and/or its assigns notifies the
Holder that it will not exercise the Right of First Refusal, then the Holder may
transfer the Shares upon the terms and conditions stated in the Transfer Notice,
provided that:

                      (1) The transfer is made within 120 days of the expiration
of the Option Period; and

                      (2) The transferee agrees in writing that such Shares
shall be held subject to the provisions of this Option Agreement.

                                      -4-
<PAGE>   23

               (v) Expiration of Transfer Period. Following such 120-day period,
no transfer of the Offered Shares and no change in the terms of the transfer as
stated in the Transfer Notice (including the name of the proposed transferee)
shall be permitted without a new written Transfer Notice prepared and submitted
in accordance with the requirements of this Right of First Refusal.

               (vi) Exception for Certain Family Transfers. Anything to the
contrary contained in this section notwithstanding, the transfer of any or all
of the Shares during the Grantee's lifetime or on the Grantee's death by will or
intestacy to the Grantee's Immediate Family or a trust for the benefit of the
Grantee or the Grantee's Immediate Family shall be exempt from the provisions of
this Right of First Refusal (a "Permitted Transfer"); provided, however, that
(i) the transferee or other recipient shall receive and hold the Shares so
transferred subject to the provisions of this Option Agreement, and there shall
be no further transfer of such Shares except in accordance with the terms of
this Option Agreement and (ii) prior to any such transfer, each transferee shall
execute an agreement pursuant to which such transferee shall agree to receive
and hold such Shares subject to the provisions of this Option Agreement.
"Immediate Family" as used herein shall mean spouse, domestic partner (as
determined by the Administrator), child, lineal descendant or antecedent,
father, mother, brother or sister and the lineal descendants of such
individuals.

               (vii) Termination of Right of First Refusal. The provisions of
this Right of First Refusal shall terminate as to all Shares upon the
Registration Date.

               (viii) Additional Shares or Substituted Securities. In the event
of any transaction described in Section 11 of the Plan, any new, substituted or
additional securities or other property which is by reason of any such
transaction distributed with respect to the Shares shall be immediately subject
to the Right of First Refusal, but only to the extent the Shares are at the time
covered by such right.

               (ix) Corporate Transaction. Immediately prior to the consummation
of a Corporate Transaction described in Sections 2(m)(i),(ii), and (iii) of the
Plan, the Right of First Refusal shall automatically lapse in its entirety,
except to the extent this Option Agreement is assumed by the successor
corporation (or its Parent) in connection with such Corporate Transaction, in
which case the Right of First Refusal shall apply to the new capital stock or
other property received in exchange for the Shares in consummation of the
Corporate Transaction, but only to the extent the Shares are at the time covered
by such right. The Grantee acknowledges and agrees that the Shares are subject
to a right of first refusal ("Right of First Refusal") as set forth in the
Bylaws of the Company and that, except in compliance with such right of first
refusal, neither the Grantee nor a transferee (either being sometimes referred
to herein as the "Holder") shall sell, hypothecate, encumber or otherwise
transfer any Shares or any right or interest therein.

        (k) Company's Repurchase Right.

               (i) Grant of Repurchase Right. The Company is hereby granted the
right (the "Repurchase Right"), exercisable at any time (i) during the ninety
(90) day period following the Termination Date, or (ii) during the ninety (90)
day period following an exercise of the Option that occurs after the Termination
Date to repurchase all or any portion of the Shares (the "Share Repurchase
Period").

               (ii) Exercise of the Repurchase Right. The Repurchase Right shall
be exercisable by written notice delivered to each Holder of the Shares prior to
the expiration of the Share Repurchase Period. The notice shall indicate the
number of Shares to be repurchased and the date on which the repurchase is to be
effected, such date to be not later than the last day of the Share Repurchase
Period. On the date on which the repurchase is to be effected, the Company
and/or its assigns shall pay to the

                                      -5-
<PAGE>   24

Holder in cash or cash equivalents (including the cancellation of any
purchase-money indebtedness) an amount equal to the Fair Market Value on the
date immediately prior to the day on which the repurchase is to be effected, of
the Shares which are to be repurchased from the Holder. Upon such payment or
deposit into escrow for the benefit of the Holder, the Company and/or its
assigns shall become the legal and beneficial owner of the Shares being
repurchased and all rights and interest thereon or related thereto, and the
Company shall have the right to transfer to its own name or its assigns the
number of Shares being repurchased, without further action by the Holder.

               (iii) Assignment. Whenever the Company shall have the right to
purchase Shares under this Repurchase Right, the Company may designate and
assign one or more employees, officers, directors or stockholders of the Company
or other persons or organizations, to exercise all or a part of the Company's
Repurchase Right.

               (iv) Termination of the Repurchase Right. The Repurchase Right
shall terminate with respect to any Shares for which it is not timely exercised.
In addition, the Repurchase Right shall terminate and cease to be exercisable
with respect to all Shares upon the Registration Date.

               (v) Additional Shares or Substituted Securities. In the event of
any transaction described in Section 11 of the Plan, any new, substituted or
additional securities or other property which is by reason of any such
transaction distributed with respect to the Shares shall be immediately subject
to the Repurchase Right, but only to the extent the Shares are at the time
covered by such right. Appropriate adjustments to reflect the distribution of
such securities or property shall be made to the price per share to be paid upon
the exercise of the Repurchase Right in order to reflect the effect of any such
transaction upon the Company's capital structure.

               (vi) Corporate Transaction. Immediately prior to the consummation
of a Corporate Transaction described in Sections 2(m)(i),(ii), and (iii) of the
Plan, the Repurchase Right to the extent it has not been exercised shall
automatically lapse in its entirety ,except to the extent this Option Agreement
is assumed by the successor corporation (or its Parent) in connection with such
Corporate Transaction, in which case the Repurchase Right shall apply to the new
capital stock or other property received in exchange for the Shares in
consummation of the Corporate Transaction, but only to the extent the Shares are
at the time covered by such right. Appropriate adjustments shall be made to the
price per share payable upon exercise of the Repurchase Right to reflect the
effect of the Corporate Transaction upon the Company's capital structure.

        (l) Stop-Transfer Notices. In order to ensure compliance with the
restrictions on transfer set forth in this Option Agreement, the Notice or the
Plan, the Company may issue appropriate "stop transfer" instructions to its
transfer agent, if any, and, if the Company transfers its own securities, it may
make appropriate notations to the same effect in its own records.

        (m) Refusal to Transfer. The Company shall not be required (i) to
transfer on its books any Shares that have been sold or otherwise transferred in
violation of any of the provisions of this Option Agreement or (ii) to treat as
owner of such Shares or to accord the right to vote or pay dividends to any
purchaser or other transferee to whom such Shares shall have been so
transferred.

        (n) Tax Consequences. Set forth below is a brief summary as of the date
of this Option Agreement of some of the federal tax consequences of exercise of
the Option and disposition of the Shares. THIS SUMMARY IS NECESSARILY
INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. THE GRANTEE
SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING THE OPTION OR DISPOSING OF THE
SHARES.

                                      -6-
<PAGE>   25

               (i) Exercise of Incentive Stock Option. If the Option qualifies
as an Incentive Stock Option, there will be no regular federal income tax
liability upon the exercise of the Option, although the excess, if any, of the
Fair Market Value of the Shares on the date of exercise over the Exercise Price
will be treated as income for purposes of the alternative minimum tax for
federal tax purposes and may subject the Grantee to the alternative minimum tax
in the year of exercise.

               (ii) Exercise of Incentive Stock Option Following Disability. If
the Grantee's Continuous Service terminates as a result of Disability that is
not total and permanent disability as defined in Section 22(e)(3) of the Code,
to the extent permitted on the date of termination, the Grantee must exercise an
Incentive Stock Option within three (3) months of such termination for the
Incentive Stock Option to be qualified as an Incentive Stock Option.

               (iii) Exercise of Non-Qualified Stock Option. On exercise of a
Non-Qualified Stock Option, the Grantee will be treated as having received
compensation income (taxable at ordinary income tax rates) equal to the excess,
if any, of the Fair Market Value of the Shares on the date of exercise over the
Exercise Price. If the Grantee is an Employee or a former Employee, the Company
will be required to withhold from the Grantee's compensation or collect from the
Grantee and pay to the applicable taxing authorities an amount in cash equal to
a percentage of this compensation income at the time of exercise, and may refuse
to honor the exercise and refuse to deliver Shares if such withholding amounts
are not delivered at the time of exercise.

               (iv) Disposition of Shares. In the case of a Non-Qualified Stock
Option, if Shares are held for more than one year, any gain realized on
disposition of the Shares will be treated as long-term capital gain for federal
income tax purposes and subject to tax at a maximum rate of 20%. In the case of
an Incentive Stock Option, if Shares transferred pursuant to the Option are held
for more than one year after receipt of the Shares and are disposed more than
two years after the Date of Award, any gain realized on disposition of the
Shares also will be treated as capital gain for federal income tax purposes and
subject to the same tax rates and holding periods that apply to Shares acquired
upon exercise of a Non-Qualified Stock Option. If Shares purchased under an
Incentive Stock Option are disposed of prior to the expiration of such one-year
or two-year periods, any gain realized on such disposition will be treated as
compensation income (taxable at ordinary income rates) to the extent of the
difference between the Exercise Price and the lesser of (i) the Fair Market
Value of the Shares on the date of exercise, or (ii) the sale price of the
Shares.

        (o) Lock-Up Agreement.

               (i) Agreement. The Grantee, if requested by the Company and the
lead underwriter of any public offering of the Common Stock or other securities
of the Company (the "Lead Underwriter"), hereby irrevocably agrees not to sell,
contract to sell, grant any option to purchase, transfer the economic risk of
ownership in, make any short sale of, pledge or otherwise transfer or dispose of
any interest in any Common Stock or any securities convertible into or
exchangeable or exercisable for or any other rights to purchase or acquire
Common Stock (except Common Stock included in such public offering or acquired
on the public market after such offering) during the 180-day period following
the effective date of a registration statement of the Company filed under the
Securities Act of 1933, as amended, or such shorter period of time as the Lead
Underwriter shall specify. The Grantee further agrees to sign such documents as
may be requested by the Lead Underwriter to effect the foregoing and agrees that
the Company may impose stop-transfer instructions with respect to such Common
Stock subject until the end of such period. The Company and the Grantee
acknowledge that each Lead Underwriter of a public offering of the Company's
stock, during the period of such offering and for the 180-day period thereafter,
is an intended beneficiary of this Section 16.

                                      -7-
<PAGE>   26

               (ii) No Amendment Without Consent of Underwriter. During the
period from identification as a Lead Underwriter in connection with any public
offering of the Company's Common Stock until the earlier of (i) the expiration
of the lock-up period specified in Section 16(a) in connection with such
offering or (ii) the abandonment of such offering by the Company and the Lead
Underwriter, the provisions of this Section 16 may not be amended or waived
except with the consent of the Lead Underwriter.

        (p) Entire Agreement: Governing Law. The Notice, the Plan and this
Option Agreement constitute the entire agreement of the parties with respect to
the subject matter hereof and supersede in their entirety all prior undertakings
and agreements of the Company and the Grantee with respect to the subject matter
hereof, and may not be modified adversely to the Grantee's interest except by
means of a writing signed by the Company and the Grantee. Nothing in the Notice,
the Plan and this Option Agreement (except as expressly provided therein) is
intended to confer any rights or remedies on any persons other than the parties.
The Notice, the Plan and this Option Agreement are to be construed in accordance
with and governed by the internal laws of the State of California without giving
effect to any choice of law rule that would cause the application of the laws of
any jurisdiction other than the internal laws of the State of California to the
rights and duties of the parties. Should any provision of the Notice, the Plan
or this Option Agreement be determined by a court of law to be illegal or
unenforceable, such provision shall be enforced to the fullest extent allowed by
law and the other provisions shall nevertheless remain effective and shall
remain enforceable.

        (q) Headings. The captions used in the Notice and this Option Agreement
are inserted for convenience and shall not be deemed a part of the Option for
construction or interpretation.

        (r) Dispute Resolution. The provisions of this Section 19 shall be the
exclusive means of resolving disputes arising out of or relating to the Notice,
the Plan and this Option Agreement. The Company, the Grantee, and the Grantee's
assignees (the "parties") shall attempt in good faith to resolve any disputes
arising out of or relating to the Notice, the Plan and this Option Agreement by
negotiation between individuals who have authority to settle the controversy.
Negotiations shall be commenced by either party by notice of a written statement
of the party's position and the name and title of the individual who will
represent the party. Within thirty (30) days of the written notification, the
parties shall meet at a mutually acceptable time and place, and thereafter as
often as they reasonably deem necessary, to resolve the dispute. If the dispute
has not been resolved by negotiation, the parties agree that any suit, action,
or proceeding arising out of or relating to the Notice, the Plan or this Option
Agreement shall be brought in the United States District Court for the Northern
District of California (or should such court lack jurisdiction to hear such
action, suit or proceeding, in a California state court in the County of San
Francisco) and that the parties shall submit to the jurisdiction of such court.
The parties irrevocably waive, to the fullest extent permitted by law, any
objection the party may have to the laying of venue for any such suit, action or
proceeding brought in such court. THE PARTIES ALSO EXPRESSLY WAIVE ANY RIGHT
THEY HAVE OR MAY HAVE TO A JURY TRIAL OF ANY SUCH SUIT, ACTION OR PROCEEDING. If
any one or more provisions of this Section 19 shall for any reason be held
invalid or unenforceable, it is the specific intent of the parties that such
provisions shall be modified to the minimum extent necessary to make it or its
application valid and enforceable.

        (s) Notices. Any notice required or permitted hereunder shall be given
in writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States mail by certified mail (if the parties are within
the United States) or upon deposit for delivery by an internationally recognized
express mail courier service (for international delivery of notice), with
postage and fees prepaid, addressed to the other party at its address as shown
beneath its signature in the Notice, or to such other address as such party may
designate in writing from time to time to the other party.

                                      -8-
<PAGE>   27

                              ESCENE NETWORKS, INC.

                            2000 STOCK INCENTIVE PLAN

                                 EXERCISE NOTICE

eSCENE Networks, Inc.
649 Mission Street
2nd Floor
San Francisco, CA  94105

Attention: Secretary

        1. Effective as of today, _________, ___ the undersigned (the "Grantee")
hereby elects to exercise the Grantee's option to purchase ___________ shares of
the Common Stock (the "Shares") of eSCENE Networks, Inc. (the "Company") under
and pursuant to the Company's 2000 Stock Incentive Plan, as amended from time to
time (the "Plan") and the [ ] Incentive [ ] Non-Qualified Stock Option Award
Agreement (the "Option Agreement") and Notice of Stock Option Award (the
"Notice") dated ______________, ________. Unless otherwise defined herein, the
terms defined in the Plan shall have the same defined meanings in this Exercise
Notice.

        2. Representations of the Grantee. The Grantee acknowledges that the
Grantee has received, read and understood the Notice, the Plan and the Option
Agreement and agrees to abide by and be bound by their terms and conditions.

        3. Rights as Stockholder. Until the stock certificate evidencing such
Shares is issued (as evidenced by the appropriate entry on the books of the
Company or of a duly authorized transfer agent of the Company), no right to vote
or receive dividends or any other rights as a stockholder shall exist with
respect to the Shares, notwithstanding the exercise of the Option. The Company
shall issue (or cause to be issued) such stock certificate promptly after the
Option is exercised. No adjustment will be made for a dividend or other right
for which the record date is prior to the date the stock certificate is issued,
except as provided in Section 11(a) of the Plan.

        The Grantee shall enjoy rights as a stockholder until such time as the
Grantee disposes of the Shares or the Company and/or its assignee(s) exercises
the Right of First Refusal or the Repurchase Right. Upon such exercise, the
Grantee shall have no further rights as a holder of the Shares so purchased
except the right to receive payment for the Shares so purchased in accordance
with the provisions of the Option Agreement, and the Grantee shall forthwith
cause the certificate(s) evidencing the Shares so purchased to be surrendered to
the Company for transfer or cancellation.

        4. Delivery of Payment. The Grantee herewith delivers to the Company the
full Exercise Price for the Shares, which, to the extent selected, shall be
deemed to be satisfied by use of the broker-dealer sale and remittance procedure
to pay the Exercise Price provided in Section 4(d) of the Option Agreement.

<PAGE>   28

        5. Tax Consultation. The Grantee understands that the Grantee may suffer
adverse tax consequences as a result of the Grantee's purchase or disposition of
the Shares. The Grantee represents that the Grantee has consulted with any tax
consultants the Grantee deems advisable in connection with the purchase or
disposition of the Shares and that the Grantee is not relying on the Company for
any tax advice.

        6. Taxes. The Grantee agrees to satisfy all applicable federal, state
and local income and employment tax withholding obligations and herewith
delivers to the Company the full amount of such obligations or has made
arrangements acceptable to the Company to satisfy such obligations. In the case
of an Incentive Stock Option, the Grantee also agrees, as partial consideration
for the designation of the Option as an Incentive Stock Option, to notify the
Company in writing within thirty (30) days of any disposition of any shares
acquired by exercise of the Option if such disposition occurs within two (2)
years from the Award Date or within one (1) year from the date the Shares were
transferred to the Grantee. If the Company is required to satisfy any federal,
state or local income or employment tax withholding obligations as a result of
such an early disposition, the Grantee agrees to satisfy the amount of such
withholding in a manner that the Administrator prescribes.

        7. Restrictive Legends. The Grantee understands and agrees that the
Company shall cause the legends set forth below or legends substantially
equivalent thereto, to be placed upon any certificate(s) evidencing ownership of
the Shares together with any other legends that may be required by the Company
or by state or federal securities laws:

                        THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN
                REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE "ACT") OR ANY
                STATE SECURITIES LAWS AND MAY NOT BE OFFERED, SOLD OR OTHERWISE
                TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL REGISTERED
                UNDER THE ACT OR, IN THE OPINION OF COUNSEL SATISFACTORY TO THE
                ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR TRANSFER, PLEDGE
                OR HYPOTHECATION IS IN COMPLIANCE THEREWITH.

                        THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT
                TO CERTAIN RESTRICTIONS ON TRANSFER, A RIGHT OF FIRST REFUSAL
                AND A REPURCHASE RIGHT HELD BY THE ISSUER OR ITS ASSIGNEE(S) AS
                SET FORTH IN THE OPTION AGREEMENT BETWEEN THE ISSUER AND THE
                ORIGINAL HOLDER OF THESE SHARES, A COPY OF WHICH MAY BE OBTAINED
                AT THE PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER
                RESTRICTIONS, RIGHT OF FIRST REFUSAL AND REPURCHASE RIGHT ARE
                BINDING ON TRANSFEREES OF THESE SHARES.

        8. Successors and Assigns. The Company may assign any of its rights
under this Exercise Notice to single or multiple assignees, and this agreement
shall inure to the benefit of the successors and assigns of the Company. Subject
to the restrictions on transfer herein set forth, this Exercise Notice shall be
binding upon the Grantee and his or her heirs, executors, administrators,
successors and assigns.

                                      -2-
<PAGE>   29

        9. Headings. The captions used in this Exercise Notice are inserted for
convenience and shall not be deemed a part of this agreement for construction or
interpretation.

        10. Dispute Resolution. The provisions of Section 20 of the Option
Agreement shall be the exclusive means of resolving disputes arising out of or
relating to this Exercise Notice.

        11. Governing Law; Severability. This Exercise Notice is to be construed
in accordance with and governed by the internal laws of the State of California
(as permitted by Section 1646.5 of the California Civil Code, or any similar
successor provision) without giving effect to any choice of law rule that would
cause the application of the laws of any jurisdiction other than the internal
laws of the State of California to the rights and duties of the parties. Should
any provision of this Exercise Notice be determined by a court of law to be
illegal or unenforceable, such provision shall be enforced to the fullest extent
allowed by law and the other provisions shall nevertheless remain effective and
shall remain enforceable.

        12. Notices. Any notice required or permitted hereunder shall be given
in writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States mail by certified mail (if the parties are within
the United States) or upon deposit for delivery by an internationally recognized
express mail courier service (for international delivery of notice), with
postage and fees prepaid, addressed to the other party at its address as shown
below beneath its signature, or to such other address as such party may
designate in writing from time to time to the other party.

        13. Further Instruments. The parties agree to execute such further
instruments and to take such further action as may be reasonably necessary to
carry out the purposes and intent of this agreement.

        14. Entire Agreement. The Notice, the Plan and the Option Agreement are
incorporated herein by reference and together with this Exercise Notice
constitute the entire agreement of the parties with respect to the subject
matter hereof and supersede in their entirety all prior undertakings and
agreements of the Company and the Grantee with respect to the subject matter
hereof, and may not be modified adversely to the Grantee's interest except by
means of a writing signed by the Company and the Grantee. Nothing in the Notice,
the Plan, the Option Agreement and this Exercise Notice (except as expressly
provided therein) is intended to confer any rights or remedies on any persons
other than the parties.

                                      -3-
<PAGE>   30

Submitted by:                              Accepted by:

GRANTEE:                                   ESCENE NETWORKS, INC.

                                           By: _________________________________

_____________________________________      Title: ______________________________
             (Signature)

Address:                                   Address:

_____________________________________      649 Mission Street
_____________________________________      2nd Floor
                                           San Francisco, CA 94105

                                      -4-
<PAGE>   31

                                    EXHIBIT B

                              ESCENE NETWORKS, INC

                            2000 STOCK INCENTIVE PLAN

                       INVESTMENT REPRESENTATION STATEMENT

GRANTEE:              ____________________________________

COMPANY:              eSCENE Networks, Inc.

SECURITY:             COMMON STOCK

AMOUNT:               ____________________________________

DATE:                 ____________________________________

        In connection with the purchase of the above-listed Securities, the
undersigned Grantee represents to the Company the following:

               (a) Grantee is aware of the Company's business affairs and
financial condition and has acquired sufficient information about the Company to
reach an informed and knowledgeable decision to acquire the Securities. Grantee
is acquiring these Securities for investment for Grantee's own account only and
not with a view to, or for resale in connection with, any "distribution" thereof
within the meaning of the Securities Act of 1933, as amended (the "Securities
Act").

               (b) Grantee acknowledges and understands that the Securities
constitute "restricted securities" under the Securities Act and have not been
registered under the Securities Act in reliance upon a specific exemption
therefrom, which exemption depends upon among other things, the bona fide nature
of Grantee's investment intent as expressed herein. Grantee further understands
that the Securities must be held indefinitely unless they are subsequently
registered under the Securities Act or an exemption from such registration is
available. Grantee further acknowledges and understands that the Company is
under no obligation to register the Securities. Grantee understands that the
certificate evidencing the Securities will be imprinted with a legend which
prohibits the transfer of the Securities unless they are registered or such
registration is not required in the opinion of counsel satisfactory to the
Company.

               (c) Grantee is familiar with the provisions of Rule 701 and Rule
144, each promulgated under the Securities Act, which, in substance, permit
limited public resale of "restricted securities" acquired, directly or
indirectly from the issuer thereof, in a non-public offering subject to the
satisfaction of certain conditions. Rule 701 provides that if the issuer
qualifies under Rule 701 at the time of the grant of the Option

<PAGE>   32

to the Grantee, the exercise will be exempt from registration under the
Securities Act. In the event the Company becomes subject to the reporting
requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934,
ninety (90) days thereafter (or such longer period as any market stand-off
agreement may require) the Securities exempt under Rule 701 may be resold,
subject to the satisfaction of certain of the conditions specified by Rule 144,
including: (1) the resale being made through a broker in an unsolicited
"broker's transaction" or in transactions directly with a market maker (as said
term is defined under the Securities Exchange Act of 1934); and, in the case of
an affiliate, (2) the availability of certain public information about the
Company, (3) the amount of Securities being sold during any three month period
not exceeding the limitations specified in Rule 144(e), and (4) the timely
filing of a Form 144, if applicable.

        In the event that the Company does not qualify under Rule 701 at the
time of grant of the Option, then the Securities may be resold in certain
limited circumstances subject to the provisions of Rule 144, which requires the
resale to occur not less than one year after the later of the date the
Securities were sold by the Company or the date the Securities were sold by an
affiliate of the Company, within the meaning of Rule 144; and, in the case of
acquisition of the Securities by an affiliate, or by a non-affiliate who
subsequently holds the Securities less than two years, the satisfaction of the
conditions set forth in sections (a), (b), and (c) of the paragraph immediately
above.

               (d) Grantee further understands that in the event all of the
applicable requirements of Rule 701 or 144 are not satisfied, registration under
the Securities Act, compliance with Regulation A, or some other registration
exemption will be required; and that, notwithstanding the fact that Rules 144
and 701 are not exclusive, the Staff of the Securities and Exchange Commission
has expressed its opinion that persons proposing to sell private placement
securities other than in a registered offering and otherwise than pursuant to
Rules 144 or 701 will have a substantial burden of proof in establishing that an
exemption from registration is available for such offers or sales, and that such
persons and their respective brokers who participate in such transactions do so
at their own risk. Grantee understands that no assurances can be given that any
such other registration exemption will be available in such event.

               (e) Grantee represents that he is a resident of the state of
_____________________.

                                          Signature of Grantee:

                                          ______________________________________

                                          Date: _____________, ________

                                      -2-<PAGE>   1
                            STOCK PURCHASE AGREEMENT

     This Stock Purchase Agreement (the "Agreement") is made as of July 31,
2001 between Questcor Pharmaceuticals, Inc., a California corporation (the
"Company"), and Sigma-Tau Finance Holding S.A. (the "Purchaser").

     WHEREAS, the Company wishes to sell and the Purchaser desires to purchase
an aggregate of 5,279,034 newly authorized shares (the "Shares") of the
Company's Common Stock, no par value per share (the "Common Stock").

     NOW, THEREFORE, the parties hereto hereby agree as follows:

     1.   Purchase and Sale of the Shares.

               1.1  Aggregate Sale. Subject to the terms and conditions hereof,
the Company shall issue and sell to Purchaser an aggregate of 5,279,034 Shares
of Common Stock. The purchase price will be $0.663 per share, for an aggregate
purchase price of $3,500,000.

               1.2  Payment of Purchase Price. On or prior to the Closing Date
(as hereinafter defined), Purchaser will deliver to the Company $3,500,000 (the
"Purchase Price").

     2.   Closing Date and Delivery.

               2.1  Closing Date. The closing of the purchase and sale of the
Shares hereunder (the "Closing") will be held at such time (the "Closing Date")
as shall be agreed upon by the Company and the Purchaser and shall occur at the
offices of the Company, 3260 Whipple Road, Union City, CA 94587, but in no event
shall the Closing Date be later than August 6, 2001.

               2.2  Deliveries at Closing. At the Closing, the Company shall
deliver to the Purchaser a stock certificate registered in Purchaser's name
representing the Shares purchased by Purchaser. At the Closing, Purchaser shall
deliver to the Company proper payment of the Purchase Price in lawful money of
the United States of America in the form of a check or wire transfer of
immediately available funds. Purchaser's obligation to purchase the Shares shall
be subject to the following conditions:

                    (a)  the accuracy of the representations and warranties made
                         by the Company herein and the fulfillment of those
                         undertakings of the Company to be fulfilled prior to
                         Closing; and

                    delivery of the certificates representing the Shares.

The Company's obligation to sell the Shares shall be subject to the following
conditions:

                    (a)  the accuracy of the representations and warranties made
                         by Purchaser herein and the fulfillment of those
                         undertakings of Purchaser to be fulfilled prior to the
                         Closing; and

                    (b)  Purchaser's payment of the Purchase Price to the
                         Company.

     3.   Representations and Warranties by the Company. The Company represents
and warrants to and covenants and agrees with Purchaser that, except as set
forth in the Disclosure Schedule attached hereto as Schedule II (the "Disclosure
Schedule") or in the SEC Reports (as hereinafter defined):

               3.1  Organization and Standing. The Company is a corporation
duly organized, validly existing and in good standing under the laws of the
State of California, and has the requisite corporate power and authority to own,
lease and operate its properties and to carry on its business as now being
conducted. The Company is qualified

1

<PAGE>   2
to do business and is in good standing as a foreign corporation in every
jurisdiction in which the failure to so qualify would have a material adverse
effect on the financial condition or business of the Company.

     3.2 Changes. Except as set forth in the SEC Reports, since March 31, 2001,
the Company has not, to the extent material to the Company: (a) incurred any
debts, obligations or liabilities, absolute, accrued or contingent, whether due
or to become due, other than in the ordinary course of business; (b) mortgaged,
pledged or subjected to lien, charge, security interest or other encumbrance any
of its assets, tangible or intangible, other than in the ordinary course of
business; (c) waived any debt owed to the Company or its subsidiaries, other
than in the ordinary course of business; (d) satisfied or discharged any lien,
claim or encumbrance or paid any obligation other than in the ordinary course of
business; (e) declared or paid any dividends, other than in the ordinary course
of business; or (f) entered into any transaction other than in the usual and
ordinary course of business.

     3.3 Litigation. Except as set forth in the Disclosure Schedule or the SEC
Reports, there are no legal actions, suits, arbitrations or other legal,
administrative or governmental proceedings pending or, to the Company's
knowledge, threatened against the Company or its properties, assets or business,
and the Company is not aware of any facts which might result in or form the
basis for any such action, suit or other proceeding, in each case which, if
adversely determined, would individually or in the aggregate have a material
adverse effect on the financial condition or business of the Company.

     3.4 Compliance with Other Instruments. The execution and delivery of, and
the performance and compliance with, this Agreement and the transactions
contemplated hereby, with or without the giving of notice or passage of time,
will not (a) result in any breach of, or constitute a default under, or result
in the imposition of any lien or encumbrance upon any asset or property of the
Company pursuant to any agreement or other instrument to which the Company is a
party or by which it or any of its properties, assets or rights is bound or
affected, except for such matters which, either individually or in the
aggregate, would not have a material adverse effect on the financial condition
or business of the Company, (b) violate the Amended and Restated Articles of
Incorporation (the "Articles") or Bylaws (the "Bylaws") of the Company, or any
law, rule, regulation, judgment, order or decree; or (c) except for (i) the
listing of the Shares on the AMEX and such consents, approvals, authorizations,
registrations or qualifications as may be required under the Securities Exchange
Act of 1934, as amended (the "Exchange Act"), and (ii) applicable state
securities laws in connection with the purchase of the Shares by the Purchaser,
require any consent, approval, authorization or order of or filing with any
court or governmental agency or body, except for such matters which, either
individually or in the aggregate, would not have a material adverse effect on
the financial condition or business of the Company. The Company is not in
violation of its Articles or Bylaws nor in violation of, or in default under,
any lien, mortgage, lease, agreement or instrument, except for such defaults
which would not, individually or in the aggregate, have a material adverse
effect on the financial condition or business of the Company. The Company is not
subject to any restriction which would prohibit the Company from entering into
or performing its obligations under this Agreement, except for such restrictions
which would not, individually or in the aggregate, have a material adverse
effect on the ability of the Company to perform its obligations under this
Agreement.

     3.5 Reports and Financial Statements. As of their respective filing dates,
the Company's Amendment No. 1 to its Annual Report on Form 10-K for the fiscal
year ended December 31, 2000 filed on Form 10-K/A with the SEC on April 30,
2001, the Company's Proxy Statement in connection with the 2001 Annual Meeting
of Shareholders and all Forms 10-Q and 8-K filed by the Company with the
Securities and Exchange Commission (the "SEC") after December 31, 2000, in each
case without exhibits thereto (the "SEC Reports") were prepared in all material
respects in accordance with the requirements of the Securities Act of 1933 (the
"Securities Act") or the Exchange Act, as the case may be, and the rules and
regulations of the SEC thereunder applicable to such SEC Reports. The SEC
Reports, when read as a whole do not contain any untrue statements of a material
fact and do not omit to state a material fact necessary to make the statements
therein, in light of the circumstances under which they were made, not
misleading. The audited consolidated financial statements and unaudited interim
financial statements of the Company included in the SEC Reports have been
prepared in accordance with United States generally accepted accounting
principles applied on a consistent basis (except as may be indicated therein or
in the notes thereto) and fairly present, in all material respects, the
financial position of the Company as at the dates thereof and the results of its
operations and cash flows for the periods then ended subject, in the case of the
unaudited interim financial statements, to normal year-end adjustments and any
other adjustments described in such financial statements.

2
<PAGE>   3
     3.6 Shares.  The Shares, when issued and paid for pursuant to the terms of
this Agreement, will be duly and validly authorized, issued and outstanding,
fully paid, nonassessable and free and clear of all pledges, liens, encumbrances
and restrictions (other than arising under federal or state securities laws).
The issuance of the Shares is not subject to any preemptive or other similar
rights.

     3.7 Capital Stock.  As of June 30, 2001, 29,157,576 shares of the Common
Stock were issued and outstanding, 2,155,715 shares of the Company's Series A
Preferred Stock, no par value per share (the "Preferred Stock"), were issued and
outstanding, which are convertible into 2,155,715 shares of Common Stock, and
options and/or warrants to purchase 6,158,329 shares of Common Stock were issued
and outstanding. All of the outstanding shares of the Company's capital stock
are validly issued, fully paid and nonassessable. Except as set forth in this
Section 3.7, as of June 30, 2001, thee are no outstanding subscriptions,
options, warrants, calls, contracts, demands, commitments, conversion rights or
other agreements or arrangements of any character or nature whatever under which
the Company is or may be obligated to issue its Common Stock, Preferred Stock or
warrants or options to purchase the Common Stock or the Preferred Stock. No
holder of any security of the Company is entitled to any preemptive or similar
rights to purchase any securities of the Company.

     3.8 Corporate Acts and Proceedings.  This Agreement has been duly
authorized by the requisite corporate action and has been duly executed and
delivered by an authorized officer of the Company, and is a valid and binding
obligation of the Company, enforceable in accordance with its terms, except as
such enforceability may be limited by bankruptcy, insolvency, moratorium,
reorganization or other similar laws affecting the enforcement of creditors'
rights generally and as to limitations on the enforcement of the remedy of
specific performance and other equitable remedies. The requisite corporate
action necessary for the authorization, reservation, issuance and delivery of
the Shares has been taken by the Company.

     3.9 No Implied Representations.  All of the Company's representations and
warranties are contained in this Agreement, and no other representations or
warranties by the Company shall be implied.

     3.10 Filing of Reports.  Since the Company's Amendment No. 1 to its Annual
Report on Form 10-K for the fiscal year ended December 31, 2000 filed on Form
10-K/A with the SEC on April 30, 2001, the Company has filed with the SEC all
reports and other material required to be filed by it therewith pursuant to
Section 13, 14 or 15(d) of the Exchange Act.

     3.11 Compliance with Laws.  The business and operations of the Company have
been conducted in accordance with all applicable laws, rules and regulations of
all governmental authorities, except for such violations which would not,
individually or in the aggregate, have a material adverse effect on the
financial condition or business of the Company.

     3.12 Proprietary Rights.  To the knowledge of the Company, the Company owns
or is licensed to use all patents, patent applications, inventions, trademarks,
trade names, applications for registration of trademarks, service marks, service
mark applications, copyrights, trade secrets, licenses and rights in any thereof
and any other intangible property and assets (herein called the "Proprietary
Rights") which are material to the business of the Company. Except as would not
have a material adverse effect on the financial condition or business of the
Company, the Company does not have any knowledge of, and the Company has not
given or received any notice of, any pending conflicts with or infringement of
the rights of others with respect to any Proprietary Rights. Except as would not
have a material adverse effect on the financial condition or business of the
Company, no action, suit, arbitration, or legal, administrative or other
proceeding, or investigation is pending or, to the knowledge of the Company,
threatened, which involves any Proprietary Rights. Except as would not have a
material adverse effect on the financial condition or business of the Company,
to the knowledge of the Company, no Proprietary Rights used by the Company, and
no services or products sold by the Company, conflict with or infringe upon any
proprietary rights owned or licensed by any third party. Except as would not
have a material adverse effect on the financial condition or business of the
Company, no claims have been asserted by any person with respect to the validity
of the Company's ownership or right to use the Proprietary Rights and, to the
knowledge of the Company, there is no reasonable basis for any such claim to be
successful.

     3.13 Compliance with Environmental Laws.  Except as would not, singly or in
the aggregate, have a material adverse effect on the financial condition or
business of the Company, the Company is not in violation of

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<PAGE>   4

any applicable statute, law or regulation relating to the environment or
occupational health and safety, and to the Company's knowledge, no expenditures
material to the Company are or will be required to comply with any such existing
statute, law or regulation. To the Company's knowledge, the Company does not
have any liability to any governmental authority or other third party arising
under or as a result of any past or existing statute, law or regulation, which
liability would be material to the Company.

          3.14  Permits, Licenses, Etc.  The Company owns, possesses or has
obtained, and is operating in compliance with, all governmental and
administrative licenses, permits, certificates, registrations, approvals,
consents and other authorizations (collectively, "Permits") necessary to own or
lease (as the case may be) and operate its properties, whether tangible or
intangible, and to conduct its businesses or operations as currently conducted,
except such licenses, permits, certificates, registrations, approvals, consents
and authorizations the failure of which to obtain would not have a material
adverse effect on the financial condition or business of the Company. The
Company has not received any notice of proceedings relating to the revocation,
modification or suspension of any Permits or any circumstance which would lead
it to believe that such proceedings are reasonably likely.

          3.15  Insurance.  The Company maintains insurance of the type and in
the amount which the Company believes is reasonably adequate for its business,
including, but not limited to, insurance covering all real and personal property
owned or leased by the Company against theft, damage, destruction, acts of
vandalism and all other risks customarily insured against by similarly situated
companies, all of which insurance is in full force and effect.

          3.16  Brokers or Finders.  No agent, broker, investment banker or
other person (as such term is defined in the Securities Act) is or will be
entitled to any broker's or finder's fee or any other commission or similar fee
from the Company in connection with any of the transactions contemplated hereby.

     4.   Representations and Warranties by the Purchaser; Restrictions on
Transfer and Future Purchases. Purchaser represents and warrants to, and
covenants and agrees with, the Company, as of the Closing Date, as follows:

          4.1  Authorization.  Purchaser has all requisite legal and corporate
or other power and capacity and has taken all requisite corporate or other
action to execute and deliver this Agreement, to purchase the Shares to be
purchased by it and to carry out and perform all of its obligations under this
Agreement. This Agreement constitutes the legal, valid and binding obligation of
Purchaser, enforceable in accordance with its terms, except as such
enforceability may be limited by bankruptcy, insolvency, moratorium,
reorganization or other similar laws affecting the enforcement of creditors'
rights generally and as to limitations on the enforcement of the remedy of
specific performance and other equitable remedies.

          4.2  Investor Status.  Purchaser is an "Accredited Investor" as
defined in Rule 501 of the Securities Act or a "Qualified Institutional Buyer,"
as such term is defined in Rule 144A of the Securities Act. Purchaser is aware
of the Company's business affairs and financial condition and has had access to
and has acquired sufficient information about the Company to reach an informed
and knowledgeable decision to acquire the Shares. Purchaser has such business
and financial experience as is required to give it the capacity to protect its
own interests in connection with the purchase of the Shares and is able to bear
the risks of an investment in the Shares. Purchaser is not itself a "broker" or
a "dealer" as defined in the Exchange Act and is not an "affiliate" of the
Company as defined in Rule 405 of the Securities Act.

          4.3  Investment Intent.  Purchaser is purchasing the Shares for its
own account as principal, for investment purposes only, and not with a present
view to or for resale, distribution or fractionalization thereof, in whole or in
part, within the meaning of the Securities Act. Purchaser understands that its
acquisition of the Shares have not been registered under the Securities Act or
registered or qualified under any state securities law in reliance on specific
exemptions therefrom, which exemptions may depend upon, among other things, the
bona fide nature of Purchaser's investment intent as expressed herein. Purchaser
has, in connection with its decision to purchase the number of Shares set forth
in this Agreement, relied solely upon the representations and warranties of the
Company contained herein. Purchaser will not, directly or indirectly, offer,
sell, pledge, transfer or otherwise dispose of (or

4

<PAGE>   5

solicit any offers to buy, purchase or otherwise acquire or take a pledge of
any of the Shares, except in compliance with the Securities Act and the rules
and regulations promulgated thereunder and all applicable state securities laws.

          4.4 Restricted Securities. Purchaser further acknowledges and
understands that the Shares may not be resold or otherwise transferred except
in a transaction registered under the Securities Act and applicable state
securities laws or an exemption therefrom, in each case as set forth in Section
5 below. Purchaser understands that until the Shares have been registered under
the Securities Act and all applicable state securities laws, the certificates
evidencing the Shares will be imprinted with a legend as provided in Section 5.

          4.5 No Legal, Tax Or Investment Advice. Purchaser understands that
nothing in this Agreement or any other materials presented to Purchaser in
connection with the purchase and sale of the Shares constitutes legal, tax or
investment advice. Purchaser has consulted such legal, tax and investment
advisors as it, its sole discretion, has deemed necessary or appropriate in
connection with its purchase of the Shares.

          4.6 Brokers or Finders. Upon the consummation of the transactions
contemplated by this Agreement, no agent, broker, investment banker or other
Person is or will be entitled to any broker's or finder's fee or any other
commission or similar fee from the Purchaser in connection with any of the
transactions contemplated hereby.

          4.7 Future Purchases. For a period of one year from the Closing Date,
Purchaser (on behalf of itself and its Affiliates) agrees not to purchase any
additional shares of Company Common Stock, or acquire beneficial ownership
thereof, not specifically contemplated by this Agreement, through the open
market or otherwise, unless first approved in writing by the Company's Board of
Directors.

     5. Restrictions on Transferability of Shares; Compliance with Securities
Act.

          5.1 Restrictive Legend. Each certificate representing the Shares
shall bear substantially the following legend (in addition to any legends
required under applicable state securities laws):

          THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED
          UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR UNDER
          THE SECURITIES LAWS OF ANY STATE. THESE SECURITIES ARE SUBJECT TO
          RESTRICTIONS ON TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED
          OR RESOLD EXCEPT AS PERMITTED UNDER THE ACT AND THE APPLICABLE STATE
          SECURITIES LAWS, PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM. THE
          ISSUER OF THESE SECURITIES MAY REQUIRE AN OPINION OF COUNSEL IN FORM
          AND SUBSTANCE SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY
          PROPOSED TRANSFER OR RESALE IS IN COMPLIANCE WITH THE ACT AND ANY
          APPLICABLE STATE SECURITIES LAWS.

          5.2 Transfer of Shares. Purchaser hereby covenants with the Company
not to make any sale of the Shares except either (a) a sale of Shares in
accordance with Rule 144, in which case the Purchaser covenants to comply with
Rule 144 and to deliver such additional certificates and documents as the
Company may reasonably request, or (b) in accordance with another exemption
from the registration requirements of the Securities Act. Without limiting the
generality of the foregoing, it is understood that Purchaser and its Affiliates
may transfer the Shares to any other Affiliate; provided that such transfer is
in accordance with an exemption from the registration requirements of the
Securities Act. "Affiliate" shall mean (i) any corporation or business entity
50% or more of the capital or voting stock of which is owned directly or
indirectly by the Purchaser, Claudio Cavazza or Paolo Cavazza; (ii) any
corporation or business entity which directly or indirectly owns 50% or more of
the capital or voting stock of the Purchaser, or (iii) any corporation or
business entity under the direct or indirect control of such corporation or
business entity as described in (i) or (ii) above. The legend set forth in
Section 5.1 will be removed from a certificate representing Shares following
and in connection with any sale of Shares pursuant to subsection (a) hereof but
not in connection with any sale of Shares pursuant to subsection (b) hereof.

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<PAGE>   6
     6.   Miscellaneous.

               6.1  Survival of Representations and Warranties. All
representations and warranties contained herein shall survive the execution and
delivery of this Agreement, any investigation at any time made by or on behalf
of the Purchaser, and the sale and purchase of the Shares and payment therefor.

               6.2  Entire Agreement. This Agreement contains the entire
agreement between the parties with respect to the subject matter hereof and
supersedes all prior and contemporaneous arrangements or understandings with
respect thereto.

               6.3  Headings. The headings of the sections of this Agreement
have been inserted for convenience of reference only and do not constitute a
part of this Agreement.

               6.4  Choice of Law. It is the intention of the parties that the
internal laws of the State of California, without regard to the body of law
controlling conflicts of law, shall govern the validity of this Agreement, the
construction of its terms and the interpretation of the rights and duties of the
parties set forth herein.

               6.5  Counterparts. This Agreement may be executed concurrently in
two or more counterparts, each of which shall be deemed an original, but all of
which together shall constitute one and the same instrument.

               6.6  Assignment; Parties in Interest. This Agreement may not be
pledged, assigned or otherwise transferred by the Purchaser except by operation
of law but all the terms and provision of this Agreement shall be binding upon
and inure to the benefit of and be enforced by the successors in interest of the
parties hereto.

               6.7  Amendments. No amendment, modification, waiver, discharge or
termination of any provision of this Agreement nor consent to any departure by
the Purchaser or the Company therefrom shall in any event be effective unless
the same shall be in writing and signed by the party to be charged with
enforcement, and then shall be effective only in the specific instance and for
the purpose for which given. No course of dealing between the parties hereto
shall operate as an amendment of, or a waiver of any right under, this
Agreement.

               6.8  Severability. Whenever possible, each provision of this
Agreement shall be interpreted in such manner as to be effective and valid, but
if any provision of this Agreement is held to be invalid or unenforceable in any
respect, such invalidity or unenforceability shall not render invalid or
unenforceable any other provision of this Agreement.

               6.9  Notices. All notices, requests, consents and other
communications hereunder to any party shall be deemed to be sufficient if
contained in a written instrument delivered in person or sent by telecopy,
nationally recognized overnight courier or first class registered or certified
mail, return receipt requested, postage prepaid, addressed to such party at the
address set forth below or such other address as may hereafter be designated in
writing by such party to the other party:

                         If to the Company, to:
                         Questcor Pharmaceuticals, Inc.
                         3260 Whipple Road
                         Union City, California 94587
                         Attn: Charles J. Casamento

                         With a copy to:
                         Latham & Watkins
                         701 "B" Street, Suite 2100
                         San Diego, California 92101
                         Attn: David A. Hahn, Esq.

6

<PAGE>   7
               If to the Purchaser, to:
               Sigma-Tau Finance Holding S.A.
               administrative office: 19-21 Bd. du Prince Henri
               L-1724 Luxembourg
               LUXEMBOURG
               Attn: Mr. Antonio Nicolai/Mr. Massimo Longoni

               With a copy to:
               Cahill Gordon & Reindel
               80 Pine Street
               New York, New York 10005
               Attn: John Mitchell, Esq.

                            [SIGNATURE PAGES FOLLOW]

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<PAGE>   8

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

                                        Questcor Pharmaceuticals, Inc.

                                        By: /s/ CHARLES J. CASAMENTO
                                            ----------------------------

                                        Name: Charles J. Casamento
                                             ---------------------------

                                        Title: Chairman, President & CEO
                                              --------------------------

                                        Sigma-Tau Finance Holding S.A.

                                        By: /s/ GERMAIN BIRGEN
                                           -----------------------------

                                        Name: Germain Birgen
                                             ---------------------------

                                        Title: Director
                                              --------------------------

8

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