Document:

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                                                                    Exhibit 4.3
                                                                    -----------

                           RIVERSTONE NETWORKS, INC.
                          EMPLOYEE STOCK PURCHASE PLAN

   SECTION 1. PURPOSE OF PLAN

   The Riverstone Networks, Inc. Employee Stock Purchase Plan (the "Plan") is
intended to provide a method by which eligible employees of Riverstone
Networks, Inc. ("Riverstone") and such of its Subsidiaries as the Board of
Directors of Riverstone (the "Board") may from time to time designate
(Riverstone and such Subsidiaries being hereinafter referred to as the
"Company") may use voluntary, systematic payroll deductions to purchase shares
of common stock, $.01 par value of Riverstone (such common stock being
hereafter referred to as "Stock") and thereby acquire an interest in the future
of Riverstone. For purposes of the Plan, a "Subsidiary" is any corporation that
would be treated as a subsidiary of Riverstone under Section 424(f) of the
Internal Revenue Code of 1986, as amended (the "Code"). The Plan is intended to
qualify under Section 423 of the Code and shall be construed accordingly.

   SECTION 2. OPTIONS TO PURCHASE STOCK

   Subject to adjustment as provided in Section 14, the maximum number of
shares of Stock that may be delivered under the Plan pursuant to the exercise
of options ("Options") granted hereunder is 1,000,000 shares plus an additional
500,000 shares effective as of the first day of Riverstone's fiscal year ending
in each of 2003, 2004, 2005 and 2006. Options shall be granted under the Plan
to employees of the Company ("Employees") who meet the eligibility requirements
set forth in Section 3 hereof ("Eligible Employees"). The Stock to be delivered
upon exercise of Options under the Plan may be either shares of authorized but
unissued Stock or shares of reacquired Stock, as the Board may determine.

   SECTION 3. ELIGIBLE EMPLOYEES

   Subject to the exceptions and limitations set forth below, all Employees are
eligible to participate in the Plan.

    (a) Any Employee who immediately after the grant of an Option would own (or
pursuant to Section 423(b)(3) of the Code would be deemed to own) stock
possessing 5% or more of the total combined voting power or value of all
classes of stock of the employer corporation or of its parent or subsidiary
corporations, as defined in Section 424 of the Code, will not be eligible to
receive an Option to purchase Stock pursuant to the Plan.

    (b) No Employee will be granted an Option under the Plan that would permit
his or her rights to purchase shares of stock under all employee stock purchase
plans of the employer corporation and parent and subsidiary corporations to
accrue at a rate which exceeds $25,000 in fair market value of such stock
(determined at the time the Option is granted) for each calendar year during
which any such Option granted to such Employee is outstanding at any time, as
provided in Section 423 of the Code.

   SECTION 4. METHOD OF PARTICIPATION

   Each person who will be an Eligible Employee on the first day of an Option
Period may elect to participate in the Plan for that Option Period by executing
and delivering, by such deadline prior thereto as the Board may specify, such
enrollment forms, including a payroll deduction authorization in accordance
with Section 5, as the Board may determine. An Eligible Employee who elects to
participate in the Plan for an Option Period in accordance with the foregoing
will thereby become a participant ("Participant") on the first day of the
Option Period and will remain a Participant until his or her participation is
terminated as provided in the Plan.

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   The Plan shall operate on the basis of consecutive six-month Option Periods
commencing January 1 or July 1 and ending (unless abbreviated pursuant to
Section 16) on the next following June 30 or December 31; provided, that the
first Option Period shall be a short period commencing on the first day of the
month coinciding with or next following the date on which Cabletron Systems,
Inc. ("Cabletron") distributes to its shareholders the stock of Riverstone held
by Cabletron and ending on the next following December 31 or, if earlier, the
next following June 30.

   SECTION 5. PAYROLL DEDUCTION

   Each payroll deduction authorization will request withholding at a rate (in
whole percentages) of not less than 1% nor more than 10% of Compensation per
payroll period, to be accomplished by means of payroll deductions over each
Option Period (as defined in Section 8 below) with respect to payroll dates
within the Option Period. "Compensation" for this purpose shall include and be
limited to base salary and sales commissions. A Participant may (i) change the
withholding rate of his or her payroll deduction authorization by written
notice delivered to the Company on or before the deadline specified by the
Board for the Option Period as to which the change is to be effective, and (ii)
not more than once during an Option Period may reduce (but not increase) his or
her payroll withholding percentage (within the limits described in the first
sentence of this Section 5) with respect to the remainder of such Option
Period. All amounts withheld in accordance with a Participant's payroll
deduction authorization will be credited to a withholding account maintained in
the Participant's name on the books of the Company. Amounts credited to the
withholding account shall not be required to be set aside in trust or otherwise
segregated from the Company's general assets, and shall not bear interest.

   SECTION 6. GRANT OF OPTIONS

   Subject to Section 3(b), each person who is a Participant on the first day
of an Option Period (the "applicable Period") will be granted, as of such day
and for the applicable Period, an Option entitling the Participant to purchase
up to, and the right to purchase Stock under the Option will be deemed to
accrue for the number of shares equal to, the lesser of (i) and (ii), where

(i)  is the remainder obtained by subtracting (A) the number of shares of
     Stock, if any, purchased for any earlier Option Period ending in the same
     calendar year, from (B) the number of shares of Stock obtained by dividing
     $25,000 by the fair market value of one share of Stock on the first day of
     the applicable Period, rounded down to the nearest whole share, and

(ii) is the number of shares of Stock obtained by dividing the balance of the
     Participant's withholding account on the last day of the applicable Period
     by the per-share exercise price for such Period, and rounding down to the
     nearest whole share;

provided, that the Board in its discretion may further limit the number of
shares of Stock subject to Options for any Option Period. Option grants under
this Section 6 shall be automatic and need not be separately documented.

   SECTION 7. PURCHASE PRICE

   The purchase price of Stock issued pursuant to the exercise of an Option
will be 85% of the fair market value of the Stock on (a) the date of grant of
the Option or (b) the date on which the Option is deemed exercised, whichever
is less. Fair market value for any day will mean the Closing Price of the Stock
for such day; provided, that if such day is not a trading day, fair market
value shall mean the Closing Price of the Stock for the next preceding day
which is a trading day. The "Closing Price" of the Stock on any trading day
will be the last sale price, regular way, with respect to such Stock, or, in
case no such sale takes place on such day, the average of the closing bid and
asked prices, regular way, with respect to such Stock, in either case as
reported in the principal consolidated transaction reporting system with
respect to securities listed or admitted to trading

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on the New York Stock Exchange; or, if such Stock is not listed or admitted to
trading on the New York Stock Exchange, as reported in the principal
consolidated transaction reporting system with respect to securities listed on
the principal national securities exchange on which such Stock is listed or
admitted to trading; or, if such Stock is not listed or admitted to trading,
the last quoted price with respect to such Stock, or, if not so quoted, the
average of the high bid and low asked prices in the over-the-counter market
with respect to such Stock, as reported by the National Association of
Securities Dealers, Inc. Automated Quotation System or such other similar
system then in use; or, if on any such date such Stock is not quoted by any
such organization, the average of the closing bid and asked prices with respect
to such Stock, as furnished by a professional market maker making a market in
such Stock selected by the Board in good faith; or, if no such market maker is
available, the fair market value of such Stock as of such day as determined in
good faith by the Board.

   SECTION 8. EXERCISE OF OPTIONS

   If an Employee is a Participant in the Plan on the last day of an Option
Period, he or she will be deemed to have exercise the Option granted to him or
her for that Period, unless such Option shall earlier have been canceled
pursuant to Section 9. Upon such exercise, Riverstone will apply the balance of
the Participant's withholding account to the purchase of the maximum whole
number of shares of Stock available for purchase therewith under the Option (as
determined pursuant to Section 6) and as soon as practicable thereafter will
issue and deliver a certificate or certificates for the purchased shares (or
will otherwise evidence the transfer of ownership of said shares) to the
Participant and will return to him or her the balance, if any, of his or her
withholding account in excess of the total purchase price of the shares so
issued; provided, that if the balance left in the account consists solely of an
amount equal to the value of a fractional share it will be retained in the
Account and carried over to the next Option Period.

   Notwithstanding anything herein to the contrary, Riverstone's obligation to
issue and deliver shares of Stock under the Plan will be subject to the
approval required of any governmental authority in connection with the
authorization, issuance, sale or transfer of said shares, to any requirements
of any national securities exchange applicable thereto, and to compliance by
Riverstone with other applicable legal requirements in effect from time to
time.

   SECTION 9. CANCELLATION AND WITHDRAWAL

   A Participant who holds an Option under the Plan may at any time prior to
exercise thereof under Section 8 cancel all (but not less than all) of his or
her Options by written notice delivered to the Company. Upon such cancellation,
the balance in the Participant's withholding account will be returned to the
Participant.

   A Participant may terminate his or her payroll deduction authorization as of
any date by written notice delivered to the Company prior to such date. A
Participant who voluntarily terminates his or her payroll deduction
authorization prior to the last day of an Option Period will be deemed to have
canceled all of his or her Options then outstanding.

   SECTION 10. TERMINATION OF EMPLOYMENT

   Except as otherwise provided in Section 11, upon the termination of a
Participant's employment with the Company for any reason, he or she will cease
to be a Participant, any Option held by him or her under the Plan will be
deemed canceled, the balance of his or her withholding account will be
returned, and he or she will have no further rights under the Plan.

   SECTION 11. DEATH OF PARTICIPANT

   A Participant may elect that if death should occur during an Option Period
the balance, if any, of the Participant's withholding account at the time of
death will be applied at the end of the Period to the exercise of the
Participant's Option and the shares thereby purchased under the Option (plus
any balance remaining in the

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Participant's withholding account) will be delivered to the Participant's
beneficiary or beneficiaries. If the Participant has more than one beneficiary,
the Company will determine the allocation among them and its determination will
be final and binding on all persons. Except as otherwise determined by the
Board (which may establish a procedure for the designation of beneficiaries
under the Plan), a Participant's beneficiary(ies) for purposes of the Plan
shall be (i) such person or persons as are treated as the Participant's
beneficiary(ies) for purposes of the Company group life insurance plan
applicable to the Participant, or (ii) in the absence of any beneficiary
determined under clause (i) or other designated beneficiary, the Participant's
estate.

   SECTION 12. EQUAL RIGHTS; PARTICIPANT'S RIGHTS NOT TRANSFERABLE

   All Participants granted Options under the Plan with respect to any Option
Period will have the same rights and privileges. Each Participant's rights and
privileges under any Option granted under the Plan will be exercisable during
the Participant's lifetime only by him or her and except as provided at Section
11 above may not be sold, pledged, assigned, or transferred in any manner. In
the event any Participant violates or attempts to violate the terms of this
Section, any Options held by him or her may be terminated by the Company and,
upon return to the Participant of the balance of his or her withholding
account, all of the Participant's rights under the Plan will terminate.

   SECTION 13. EMPLOYMENT RIGHTS

   Nothing contained in the provisions of the Plan will be construed as giving
to any Employee any right of employment or as interfering with the right of the
Company to discharge any Employee at any time.

   SECTION 14. CHANGE IN CAPITALIZATION

   In the event of any change in the outstanding Stock of Riverstone by reason
of a stock dividend, split-up, recapitalization, merger, consolidation,
reorganization, or other capital change, the aggregate number and type of
shares available under the Plan, the number and type of shares under Options
granted but not exercised, the maximum number and type of shares purchasable
under an Option, and the Option price will be appropriately adjusted.

   SECTION 15. ADMINISTRATION OF PLAN

   The Plan will be administered by the Board, which will have the right to
determine any matters which may arise regarding the interpretation and
application of the provisions of the Plan and to make, administer, and
interpret such rules and regulations as it deems necessary or advisable.
References in the Plan to the Board shall include the Board's delegates to the
extent of any delegation by the Board to such delegates of administrative
responsibilities hereunder.

   SECTION 16. AMENDMENT AND TERMINATION OF PLAN

   Riverstone reserves the right at any time to amend the Plan in any manner it
may deem advisable, by vote of the Board; provided, that any amendment that
would be treated as the adoption of a new plan for purposes of Section 423 of
the Code will have no effect unless approved by the shareholders of Riverstone
within twelve months before or after its adoption.

   The Plan may be suspended or terminated at any time by the Board. In
connection therewith, the Board may either cancel outstanding Options or
continue them and provide that they will be exercisable either at the end of
the Option Period or on such earlier date as the Board may specify (in which
case such earlier date shall be treated as the last day of the applicable
Option Period).

   SECTION 17. APPROVAL OF SHAREHOLDERS

   The Plan and the exercisability of Options granted hereunder will be subject
to the approval of the shareholders of Riverstone obtained within twelve months
before or after the date the Plan is adopted by the Board.

                                       4<PAGE>

                                  EXHIBIT 4.4

                             DATA DIMENSIONS, INC.

                        1988 INCENTIVE STOCK OPTION PLAN

                                      AND

                      1988 NONSTATUTORY STOCK OPTION PLAN
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                                   ARTICLE 1
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                       PURPOSE OF PLANS AND PLAN DOCUMENT
                       ----------------------------------

1.1   Purpose. The purpose of these Plans is to promote the growth and
      profitability of the Company by providing, through the ownership of
      Shares, incentives to attract and retain highly talented persons and to
      motivate such persons to use their best efforts on behalf of the Company
      and other Participating Companies.

1.2   Combines Plan Document. This Plan document is intended to implement and
      govern the following two separate stock option plans of the Company:

      (i) 1988 Incentive Stock Option Plan; and

      (ii) 1988 Nonstatutory Stock Option Plan.

      Unless specified otherwise, all provisions of this Plan document relate
      equally to both the 1988 Incentive Stock Option Plan and the Nonstatutory
      Stock Option Plan, which Plans are condensed into one Plan document solely
      for the purposes of administrative convenience and are not intended to
      constitute tandem plans.

                                    ARTICLE 2
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                                   DEFINITIONS
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      For the purposes of this Plan, the following terms shall have the meanings
set forth in this Article 2:

      2.1   Accrued Installment. The term "Accrued Installment" shall mean any
            vested installment of an Option.

      2.2   Board. The term "Board" shall mean the Board of Directors of the
            Company.

      2.3   Committee. The term "Committee" shall mean a committee appointed by
            the Board pursuant to Section 3.4 and constituting not less than
            three members of the Board.

      2.4   Company. The term "Company" shall mean Data Dimensions, Inc., a
            Delaware corporation, and any Participating Company.

      2.5   Director. The term "Director" shall mean a member of the Board, or a
            member of the board of directors of any Participating Company.

      2.6   Disinterested Person. The term "Disinterested Person" shall mean any
            person defined as a disinterested person under Rule 16b-3 of the
            Securities and Exchange Commission as promulgated under the Exchange
            Act.

      2.7   Effective Date. The term "Effective Date" shall mean March 14, 1988.

      2.8   Eligible Person.
<PAGE>

            (a)   For the purpose of the Incentive Stock Option Plan, the term
                  "Eligible Person" shall mean any key employee of any
                  Participating Company, as determined by the Board or
                  Committee.

            (b)   For the purpose of the Nonstatutory Stock Option Plan, the
                  term "Eligible Person" shall mean any employee or Director of
                  any Participating Company.

      2.9   Exchange Act. The term "Exchange Act" shall mean the Securities
            Exchange Act of 1934, as amended.

      2.10  Fair Market Value. The term "Fair Market Value" when used with
            respect to the determination of the option price of Options, shall
            mean the fair market value as determined in good faith by the Board
            as of the date the Option is granted.

      2.11  Incentive Stock Option. The term "Incentive Stock Option" shall mean
            any Option intended to satisfy the requirements under I.R.C. Section
            422A as an incentive stock option which qualifies for special tax
            treatment under I.R.C. Section 421 et seq.

      2.12  Incentive Stock Option Plan. The term "Incentive Stock Option Plan"
            shall mean the stock option plan of the Company set forth herein and
            which provides for the granting of Incentive Stock Options.

      2.13  I.R.C. The term "I.R.C." shall mean the Internal Revenue Code of
            1986, as it may be amended from time to time.

      2.14  Internal Revenue Code of 1954. The term "Internal Revenue Code of
            1954" shall mean the Internal Revenue Code in effect prior to the
            date of enactment of the Tax Reform Act of 1986.

      2.15  Nonstatutory Stock Option. The term "Nonstatutory Stock Option"
            shall mean any Option granted hereunder which is not an Incentive
            Stock Option.

      2.16  Nonstatutory Stock Option Plan. The term "Nonstatutory Stock Option
            Plan" shall mean the stock option plan of the Company set forth
            herein and which provides for the granting of the Options that do
            not qualify as Incentive Stock Options.

      2.17  Option. The term "Option" shall mean an option to acquire Shares
            granted under the Plans.

      2.18  Optionee. The term "Optionee" shall mean an Eligible Person who has
            been granted Options.

      2.19  Parent Corporation. The term "Parent Corporation" shall mean a
            corporation as defined in I.R.C. Section 425(e).
<PAGE>

      2.20  Participating Company. The term "Participating Company" shall mean
            the Company and any Parent Corporation of Subsidiary Corporation.

      2.21  Plan. The terms "Plan" or "Plans" shall refer collectively to the
            Incentive Stock Option Plan and the Nonstatutory Stock Option Plan
            unless a specific reference to either is indicated.

      2.22  Restricted Shareholder. The term "Restricted Shareholder" shall mean
            an Optionee granted an Incentive Stock Option who, at the time the
            Incentive Stock Option is granted, owns stock possessing more than
            10% of the total combined voting power of all classes of stock of
            the Company, with stock ownership determined in light of the
            attribution rules of I.R.C. Section 425(d).

      2.23  Shares. The term "Shares" shall mean shares of the Company's
            authorized Common Stock, $.10 par value, and may be unissued shares
            of treasury shares or shares purchased for the purpose of Plans.

      2.24  Subsidiary Corporation. The term "Subsidiary Corporation" shall mean
            a corporation as defined in I.R.C. Section 425(f).

      2.25  Terminating Transaction. The term "Terminating Transaction" shall
            mean any of the following events: (a) the dissolution or liquidation
            of the Company; (b) a reorganization, merger or consolidation of the
            Company with one or more other corporations as a result of which the
            Company goes out of existence or becomes a subsidiary of another
            corporation (which shall be deemed to have occurred if another
            corporation shall own, directly or indirectly, 80% or more of the
            aggregate voting power of all outstanding equity securities of the
            Company); (c) a sale of substantially all of the Company's assets;
            or (d) a sale to one person (or two or more persons acting in
            concert) of equity securities of the Company representing 80% or
            more of the aggregate voting power if all outstanding equity
            securities of the Company. As used herein or elsewhere in this Plan,
            the word "person" shall mean an individual, corporation,
            partnership, association or other person or entity, or any group of
            two or more of the foregoing that have agreed to act together.

      2.26  Termination Date. The term "Termination Date" shall mean March 14,
            1998.

      2.27  Total Disability. The term "Total Disability" shall mean a total and
            permanent disability as that term is defined in I.R.C. Section
            105(d)(4).

                                    ARTICLE 3
                                    ---------

                              ADMINSTRATION OF PLAN
                              ---------------------

      3.1   Administration by Board. The Plan shall be administered by the
            Board. The Board shall have full and absolute power and authority in
            its sole discretion to (I)
<PAGE>

            determine which Eligible Persons shall receive Options, (ii)
            determine the terms and conditions, not inconsistent with the
            provisions of this Plan, of any Option granted hereunder, (iv)
            determine the number of Shares which may be issued upon exercise of
            the Options, and (v) interpret the provisions of this Plan and of
            any Option granted under this Plan.

      3.2   Rules and Regulations. The Board may adopt such rules and
            regulations as the Board may deem necessary or appropriate to carry
            out the purposes of the Plan and shall have authority to do
            everything necessary of appropriate to administer the Plan.

      3.3   Binding Authority. All decisions, determinations, interpretations,
            or other actions by the Board shall be final, conclusive, and
            binding on all Eligible Persons, Optionees, Participating Companies
            and any successor-in- interest to such parties.

      3.4   Administration by Committee.

            (a)   The Board in its sole discretion may from time to time appoint
                  a Committee to administer the Plan and exercise on a
                  nonexclusive basis with the full Board all of the powers,
                  authority and discretion of the Board under this Plan. The
                  Board may from time to time remove members from, or add
                  members to, the Committee, and vacancies on the Committee
                  shall be filled by the Board. The Board may abolish the
                  Committee at any time and revest in the Board the exclusive
                  administration of the Plan.

            (b)   In establishing the Committee, the Board may but need not
                  require each member of the Committee to be a Disinterested
                  Person, and the Board may but it not requires to take such
                  other actions as are deemed necessary or advisable to conform
                  these Plans to requirements of Rule 216b-3 as promulgated
                  under the Exchange Act.

            (c)   The Committee shall report to the Board the names of Eligible
                  Persons granted Options, the number of Shares subject to each
                  Option and the terms and conditions of each such Option.

                                    ARTICLE 4
                                    ---------

                      NUMBER OF SHARES AVAILABLE FOR GRANT
                      ------------------------------------

      4.1   Maximum Aggregate Number of Shares. Subject to the following
            provisions of this Section 4.1, the maximum aggregate number of
            Shares which may be optioned and sold under the Plans in the
            aggregate is 350,000. In the event that Options granted under the
            Plans shall for any reason terminate, lapse, be forfeited, or expire
            without being exercised, the Share subject to such unexercised
            Options shall again be available for the granting of Options under
            the Plans. In the event that Shares which were previously issued by
            the Company upon exercise of an Option are reacquired by the Company
            as part of the consideration received (in
<PAGE>

            accordance with Section 6.6(b) hereof) upon the subsequent exercise
            of an Option, such reacquired Shares shall again be available for
            the granting of Options hereunder.

      4.2   Aggregate Limitation with Respect to the Participation of Directors
            under the Plans. Subject to the following provisions of the Section
            4.2, the maximum number of Shares which may be optioned and sold to
            Directors of the Company under the Nonstatutory Stock Option Plan in
            the aggregate is 50,000. In the event that Options granted under
            this limitation shall for any reason terminate, lapse, be forfeited,
            or expire without being exercise, the Shares subject to such
            unexercised Options shall again be available for the granting of
            Options under the limitations of this Section 4.2. In the event that
            Shares which were previously issued by the Company upon exercise of
            an Option granted under the limitation of this Section 4.2 are
            reacquired by the Company as part of the consideration received (I
            accordance with Section 6.6(b) hereof) upon the subsequent exercise
            of an Option, such Shares shall again be available for the granting
            of Options under the limitation of this Section 4.2.
<PAGE>

                                    ARTICLE 5
                                    ---------

                                 TERMS OF PLANS
                                 --------------

     The Plans shall be effective as of the Effective Date and shall terminate
     on the Termination Date.  No Option may be granted hereunder after the
     Termination Date.

                                    ARTICLE 6
                                    ---------

                                  OPTION TERMS
                                  ------------

      6.1   Form of Option Agreement. Any Option granted under the Plans shall
            be evidenced by an agreement ("Option Agreement") in which form as
            the Board, in its discretion, may from time to time approve. Any
            Option Agreement shall contain such terms and conditions as the
            Board may deem necessary or appropriate and which are not
            inconsistent with the provisions of the Plans.

      6.2   Grant Limitation on Incentive Stock Options. For options granted
            under the Incentive Stock Option Plan, the aggregate Fair Market
            Value (determined at the time the Option is granted) of the Shares
            for which Incentive Stock Options are exercisable for the first time
            be an Eligible Person under this Plan and any other plan of any
            Participating Company shall not exceed $100,000 in any calendar
            year.

      6.3   Option Exercise Price. The option exercise price for Shares to be
            issued under this Plan shall be determined by the Board in its sole
            discretion, but in no event shall the option exercise price be less
            than the Fair Market Value of the Shares. In the case of an
            Incentive Stock Option, if on the date of the grant of the Option
            the Optionee is a Restricted Shareholder, the option exercise price
            shall not be lass than 110% of the Fair Market Value of the Shares.
            The date of grant shall be deemed to be the date on which the Board
            authorizes the grant of the Option, unless a subsequent date is
            specified in such authorization.

      6.4   Vesting and Exercisability of Options. Subject to the limitations
            set forth herein and/or in any applicable Option Agreement entered
            into hereunder, Options granted under the Plan shall vest and be
            exercisable in accordance with the rules set forth in this Section
            6.4:

            (a)   General. Subject to the other provisions of this Section 6.4,
                  Options shall vest and become exercisable at such times and in
                  such installments as the Board shall provide in each
                  individual Option Agreement. Notwithstanding the foregoing,
                  the Board may in its sole discretion accelerate the time at
                  which an Option or installment thereof may be exercised.
                  Unless otherwise provided in this Section 6.4 or in the Option
                  Agreement pursuant to which an Option is granted, an Option
                  may be exercised when Accrued Installments accrue as provided
                  in such Option
<PAGE>

                  Agreement and at any time thereafter until, and including, the
                  day before the Option Termination Date.

            (b)   Termination of Options. All installments of an Option shall
                  expire and terminate on such date as the Board shall determine
                  ("Option Termination Date"), which in no event shall be no
                  later than 5 years from the date such Option is granted.

            (c)   Termination of Employment or Directorship Other Than by Death
                  of Total Disability. In the event that the employment of an
                  Optionee with a Participating Company is terminated for any
                  reason (other than death or Total Disability), any
                  installments under an Option held by such Optionee which have
                  not accrued as of the employment termination date or the
                  directorship termination date (whichever may be applicable)
                  shall expire and become unexercisable as of the earlier of (I)
                  three months following the employment or directorship
                  termination date or (ii) the original Option Termination Date.
                  For purposes of these Plans, an Optionee who is an employee or
                  a Director of any Participating Company shall not be deemed to
                  have incurred directorship (which ever may be applicable) so
                  long as such Optionee is an employee or Director (whichever
                  may be applicable) of any Participating Company.

            (d)   Leave of Absence. In the case of any employee on an approved
                  leave of absence, the Board may make such provision respecting
                  continuance of the Option as the Board deems appropriate,
                  except in no event shall an Option be exercisable after the
                  original Option Termination Date.

            (e)   Death or Total Disability of Optionee While Employed. In the
                  event that the employment and/or directorship of an Optionee
                  with a Participating Company is terminated by reason of death
                  or Total Disability, any unexercised Accrued Installments of
                  Options granted hereunder to such Optionee shall expire and
                  become unexercisable as of the earlier of:

                  (i)   The applicable Option Termination Date, or

                  (ii)  The first anniversary of the date of termination of
                        employment and/or directorship of such Optionee by
                        reason of the Optionee's death or Total Disability.

                  Any such Accrued Installments of a deceased Optionee may be
                  exercised prior to their expiration only by the person or
                  persons to whom the Optionee's Option right pass by will or
                  the laws of descent and distribution. Any Option installments
                  under such a deceased or disabled Optionee's Option that have
                  not accrued as of the date of the employee's termination of
                  employment and/or Director's termination of directorship due
                  to death or Total Disability shall expire and become
                  unexercisable as of the employment and/or directorship
                  termination date.
<PAGE>

            (f)   Termination of Affiliation of Participating Company.
                  Notwithstanding the foregoing provisions of this Section 6.4,
                  in the case of an Optionee who is an employee or Director of a
                  Participating Company other than the Company, upon an
                  Affiliation Termination (as defined herein) of such
                  Participating Company such Optionee shall be deemed (for all
                  purposes of these Plans) to have incurred a termination of his
                  employment or directorship (whichever may be applicable) for
                  reasons other than death or Total Disability, with such
                  termination to be deemed effective as of the effective date of
                  said Affiliation Termination. As used herein the term
                  "Affiliation Termination" shall mean, with respect to a
                  Participating Company, the termination of such Participating
                  Company's status as a Participating Company (as defined
                  herein) with respect to the Company.

      6.5   Exercise of Options. An Option may be exercised in accordance with
            this Section 6.5 as to all or any portion of the Shares covered by
            an Accrued Installment of the Option from time to time during the
            applicable option period, except that an Option shall not be
            exercisable with respect to fractions of a Share. Options may be
            exercise, in whole or in part, by giving written notice of exercise
            to the Company, which notice shall specify the number of Shares to
            be purchase price in accompanied by payment in full of the purchase
            price in accordance with Section 6.6. An Option shall be deemed
            exercised when such written notice of exercise has been received by
            the Company. No Shares shall be issued until full payment has been
            made and the Optionee has satisfied such other conditions as may
            required by this Plan; as may be required by applicable law, rules,
            or regulations; or as may be adopted or imposed be the Board. Until
            the issuance of stock certificates, no right to vote or receive
            dividends or any other rights as a stockholder shall exist with
            respect to optioned Shares notwithstanding the exercise of the
            Option. No adjustment will be made for a dividend or other rights
            for which the date is prior to the date the stock certificate is
            issued, except as proved in Section 6.9(a).

      6.6   Payment of Option Exercise Price.

            (a)   Except as otherwise provided in Section 6.6(b), the entire
                  option exercise price shall be paid at the time the Option is
                  exercised by cashier's check or such other means as deemed
                  acceptable by the Company.

            (b)   In the discretion of the Board, an Optionee may elect to pay
                  for all or some of the Optionee's Shares with Shares
                  previously acquired and owned at the time of exercise by the
                  Optionee, subject to all restrictions and limitations of
                  applicable laws, rules, and regulations and subject to the
                  satisfaction of any conditions the Board may impose, including
                  but not limited to the making of such representations and
                  warranties and the providing of such other assurances that the
                  Board may require with respect to the Optionee's title to the
                  Shares used for payment of the exercise price. Such payment
                  shall be made by delivery of certificates representing Shares,
                  duly endorsed or with duly signed stock power attached, such
                  Share to be valued on such basis as the Board shall determine.
<PAGE>

      6.7   Options Not Transferable. Options granted under this Plan may not be
            sold, pledged, hypothecated, assigned, encumbered, gifted or
            otherwise transferred or alienated in any manner, whether
            voluntarily or involuntarily by operation of law, other than by will
            or the laws of descent and distribution, and may be exercised during
            the lifetime of an Optionee only by such Optionee.

      6.8   Restrictions on Issuance of Shares.

            (a)   No Shares shall be issued or delivered upon exercise of an
                  Option unless and until there shall have been compliance with
                  all applicable requirements of the Securities Act of 1933, as
                  amended, all applicable listing requirements of any national
                  securities exchange on which Shares are then listed, and any
                  other requirement of law of any regulatory body having
                  jurisdiction over such issuance and delivery. The inability of
                  the Company to obtain any required permits, authorizations, or
                  approvals necessary for the lawful issuance and sale of any
                  Shares hereunder on terms deemed reasonable by the Board shall
                  relieve the Company, the Board, and any Committee of any
                  liability in respect of the nonissuance or sale of such Shares
                  as to which such requisite permits, authorizations, or
                  approvals shall not have been obtained.

            (b)   As a condition to the granting or exercise of any Option, the
                  Board may require the person receiving or exercising such
                  Option to make any representation and/or warranty to the
                  Company as may be required under an applicable law or
                  regulation, including but not limited to a representation that
                  the Option and/or Share are being acquired only for investment
                  and without any present intention to sell or distribute such
                  Option and/or Shares, if such a representation is required
                  under the Securities Act of 1933, as amended, or any other
                  applicable law, rule, or regulation.

            (c)   The exercise of Options under these Plans is conditioned on
                  approval of the Plans by the vote or written consent of the
                  holders of a majority of the outstanding shares of the
                  Company's Common Stock within twelve months of the adoption of
                  the Plans. In the event such shareholder approval is not
                  obtained within such time period, any Options granted
                  hereunder shall be void.

      6.9   Option Adjustments.

            (a)   If the outstanding shares of Common Stock of the Company are
                  increased, decreased, changed into or exchanged for a
                  different number or kind of shares of the Company through
                  reorganization, recapitalization, reclassification, stock
                  dividend, stock split or reverse stock split, upon
                  authorization of the Board a proportionate adjustment shall be
                  made in the number or kind of shares, and the per share option
                  price thereof, which may be issued in the aggregate and to
                  individual Optionees upon exercise
<PAGE>

                  of Options granted under the Plans; provided, however, that no
                  such adjustment need be made if, upon the advice of counsel,
                  the Board determines that such adjustment may result in the
                  receipt of federally taxable income to holders of Options
                  granted hereunder or the holders of Common Stock or other
                  classes of the Company's securities.

            (b)   Upon the occurrence of a Terminating Transaction, as of the
                  effective date of such Terminating Transaction the Plans and
                  any then outstanding Options (whether or not vested) shall
                  terminate unless (I) provision is made in writing in
                  connection with such transaction for the continuance of the
                  Plans and for the assumption of such Options, or for the
                  substitution for such Options of new options covering the
                  securities of any successor or survivor corporation in the
                  Terminating Transaction or any affiliate thereof, with such
                  adjustments as the Board deems appropriate with respect to the
                  number and kind of securities and the per share exercise price
                  under such substituted options, in which event the Plans and
                  such outstanding Options shall continue or be replaced, as the
                  case may be, in the manner and under the terms so provided; or
                  (ii) the Board otherwise shall provide in writing for such
                  adjustments as it deems appropriate in the terms and
                  conditions of the then outstanding Options (whether or not
                  vested), including without limitation (A) accelerating the
                  vesting of outstanding Options, and/or (B) providing for the
                  cancellation of Options and their automatic conversion into
                  the right to receive the securities or other properties which
                  have been entitled to receive the securities or other
                  properties which a holder of the Shares underlying such
                  Options would have entitled to receive upon the consummation
                  of such Terminating Transaction had such Shares been issued
                  and outstanding (net of the appropriate option exercise
                  prices). If, pursuant to the foregoing provisions of this
                  paragraph (b) the Plans and the Options shall terminate by
                  reason of the occurrence of a Terminating Transaction without
                  provision for any of the action(s) described in clause (I)
                  and/or (ii) hereof, then any Optionee holding outstanding
                  Options shall have the right, at such time immediately prior
                  to the consummation of the Terminating Transaction as the
                  Board shall designate, to exercise their options to the full
                  extent no theretofore exercised, including any installments
                  which have not yet become Accrued Installments (subject,
                  however, to the provisions of paragraph (c) below).

            (c)   In the event that (I) pursuant to the provisions of Section
                  6.9(b) hereof all or any portion of an outstanding Incentive
                  Stock Option (herein an "Accelerated ISO") shall first become
                  exercisable by an Optionee in a calendar year which is earlier
                  than the calendar year as provided under the applicable Option
                  Agreement at the time of the grant of such Option, and (ii)
                  such accelerated exercisability, when considered together with
                  other Incentive Stock Options of such Optionee which are first
                  exercisable during such earlier calendar year, would be
                  prohibited under the provisions of Section 6.2 hereof (as
                  interpreted by the Board in light of the requirements of
                  I.R.C. Section 422A(b)(7)), then notwithstanding the
<PAGE>

                  provisions of Section 6.9(b) said Accelerated ISO shall be
                  exercisable only to the extent permitted under the provisions
                  of Section 6.2.

            (d)   Except to the extent required in order to retain the
                  qualification of an Option as an Incentive Stock Option under
                  I.R.C. Section 422A, to the maximum extent possible any
                  adjustments authorized under this Section 6.9 with respect to
                  any outstanding Options shall be made by means of appropriate
                  adjustment to the number of Shares (or other securities) and
                  the option exercise price therefor under the unexercised
                  portions of such outstanding Options but without changing the
                  aggregate exercise price applicable to said unexercised
                  portions. In all cases, the nature and extent of adjustments
                  under this Section 6.9 shall be determined by the Board in its
                  sole discretion, and any such extent thereof, shall be final
                  and binding. No fractional shares of stock shall be issued
                  under the Plans pursuant to any such adjustment.

      6.10  Taxes. The Board shall make such provisions and take such steps as
            it deems necessary or appropriate for the withholding of any
            federal, state, local and other tax required by law to be withheld
            with respect to the grant or exercise of an Option under the Plans,
            including without limitation, the deduction of the amount of any
            such withholding tax from any compensation of other amounts payable
            to an Optionee by any member of the Participation Companies, or
            requiring an Optionee (or the Optionee's beneficiary or legal
            representative) as a condition of granting or exercising an Option
            to pay to any withheld, or to execute such other documents as the
            Board deems necessary or desirable in connection with the
            satisfaction of any applicable withholding obligation.

      6.11  Legends on Options and Stock Certificates. Each Option Agreement and
            each certificate representing Shares acquired upon exercise of an
            Option shall be endorsed with all legends, if any, required by
            applicable federal and state securities laws to be placed on the
            Option Agreement and/or the certificate. The determination of which
            legends, if any, shall be placed upon Stock Option Agreements and/or
            said Shares shall be made by the Board in its sole discretion and
            such decision shall be final and binding.

                                    ARTICLE 7
                                    ---------

                        AMENDMENT OR TERMINATION OF PLAN
                        --------------------------------

      7.1   Board Authority. The Board may amend, alter, and/or terminate the
            Plans at any time; provided, however, that unless required by
            applicable law, rule or regulation the Board shall not amend the
            Plans in the following respects without the approval of stockholders
            holding a majority interest in the Company:

            (i)   To increase the maximum number of Shares available for grant
                  under the Plan;
<PAGE>

            (ii)  To provide for the administration of the Plan other than by
                  the Board or a Committee;

            (iii) To change the manner of determining the option exercise price;

            (iv)  To change the classes of Eligible Persons or Participating
                  Companies; or

            (v)   To extent the maximum Option Period of the terms of the Plans.

      7.2   Limitation on Board Authority. The Board may amend the terms of any
            Option previously granted, prospectively or retroactively, and may
            amend the Plan in accordance with the provisions of Section 7.1;
            provided, however, that unless required by applicable law, rule, or
            regulation, no amendment of the Plan or of any Option Agreement
            shall effect in a material and adverse manner Options granted prior
            to the date of any such amendment without the consent of the
            Optionee holding any such affected Options.

      7.3   Substitution of Options. In the Board's discretion, the Board may,
            with an Optionee's consent, substitute Nonstatutory Stock Options
            for outstanding Incentive Stock Options, and any such substitution
            shall not constitute a new Option grant for the purposes of this
            Plan, and shall not require a reevaluation of the Option exercise
            price for the substituted Option. Any such substitution may be
            implemented by an amendment to the applicable Option Agreement or in
            such other manner as the Board in its discretion may determine.

                                    ARTICLE 8
                                    ---------

                               GENERAL PROVISIONS
                               ------------------

      8.1   Availability of Plans. A copy of these Plans shall be delivered to
            the Secretary of the Company and shall be shown by the Secretary to
            any Eligible Person making reasonable inquiry concerning the Plans.

      8.2   Notice. Any notice or other communication required or permitted to
            be given pursuant to the Plan under any Option Agreement must be in
            writing and may be registered or certified mail, and if given by
            registered or certified mail, shall be determined to have been given
            and received when a registered or certified letter containing such
            notice, properly addressed with postage prepaid, is deposited in the
            United States mails; and if given otherwise than by registered or
            certified mail, it shall be deemed to have been given when delivered
            to and received by the party to whom addressed. Notice shall be
            given to Eligible Persons at their most recent addresses shown in
            the Company's records. Notice to the Company shall be addressed to
            the Company at the address of the Company's principal executive
            offices, to the attention of the Secretary of the Company.
<PAGE>

      8.3   Titles and Headings. Titles and headings of sections of this Plan
            are for convenience of reference only and shall not affect the
            construction of any provisions of this Plan.

      8.4   Governing Law. This Plan shall be governed by, interpreted under,
            and construed and enforced in accordance with the internal laws, and
            not the laws pertaining to conflicts or choice of laws, of the State
            of California applicable to agreements made and to be performed
            wholly within the State of California.

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