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                                                                     EXHIBIT 4.1

                                                             AS AMENDED 11/11/02

                              PIRUS NETWORKS, INC.

                             2000 STOCK OPTION PLAN


        1.     PURPOSE OF THE PLAN.

        This stock option plan (the "Plan") is intended to encourage ownership
of the stock of Pirus Networks, Inc. (the "Company") by employees, consultants
and advisors of the Company and its subsidiaries, to induce qualified personnel
to enter and remain in the employ of the Company or its subsidiaries and
otherwise to provide additional incentive for optionees to promote the success
of its business.

        2.     STOCK SUBJECT TO THE PLAN.

        (a)    The total number of shares of the authorized but unissued or
Treasury shares of the common stock, $.01 par value per share, of the Company
(the "Common Stock") for which options may be granted under the Plan shall not
exceed seventeen million four hundred and fifty thousand (17,450,000) shares,
subject to reduction for the shares granted by the Company pursuant to the 2000
Restricted Stock Purchase Plan and shall be subject to adjustment as provided in
Section 12 hereof.

        (b)    If an option granted hereunder shall expire or terminate for any
reason without having vested fully or having been exercised in full, the
unvested and/or unpurchased shares subject thereto shall again be available for
subsequent option grants under the Plan.

        (c)    Stock issuable upon exercise of an option granted under the Plan
may be subject to such restrictions on transfer, repurchase rights or other
restrictions as shall be determined by the Committee.


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        3.     ADMINISTRATION OF THE PLAN.

        (a)    At the discretion of the Company's Board of Directors, the Plan
shall be administered either (i) by the full Board of Directors of the Company
or (ii) by a committee (the "Committee") consisting of two or more members of
the Company's Board of Directors. In the event that the full Board of Directors
is the administrator of the Plan, references herein to the Committee shall be
deemed to include the full Board of Directors. The Board of Directors may from
time to time appoint a member or members of the Committee in substitution for or
in addition to the member or members then in office and may fill vacancies on
the Committee however caused. The Committee shall choose one of its members as
Chairman and shall hold meetings at such times and places as it shall deem
advisable. A majority of the members of the Committee shall constitute a quorum
and any action may be taken by a majority of those present and voting at any
meeting.

        (b)    Any action may also be taken without the necessity of a meeting
by a written instrument signed by a majority of the Committee. The decision of
the Committee as to all questions of interpretation and application of the Plan
shall be final, binding and conclusive on all persons. The Committee shall have
the authority to adopt, amend and rescind such rules and regulations as, in its
opinion, may be advisable in the administration of the Plan. The Committee may
correct any defect or supply any omission or reconcile any inconsistency in the
Plan or in any option agreement granted hereunder in the manner and to the
extent it shall deem expedient to carry the Plan into effect and shall be the
sole and final judge of such expediency. No Committee member shall be liable to
any action or determination made in good faith.


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        4.     TYPE OF OPTIONS.

        Options granted pursuant to the Plan shall be authorized by action of
the Committee and may be designated as either incentive stock options meeting
the requirements of Section 422 of the Internal Revenue Code of 1986, as amended
(the "Code"), or non-qualified options which are not intended to meet the
requirements of such Section 422 of the Code, the designation to be in the sole
discretion of the Committee. The Plan shall be administered by the Committee in
such manner as to permit options to qualify as incentive stock options under the
Code.

        5.     ELIGIBILITY.

        Options designated as incentive stock options shall be granted only to
employees (including officers and directors who are also employees) of the
Company and any of its subsidiaries. Options designated as non-qualified options
may be granted to directors (whether or not employees), officers, employees,
consultants, and advisors of the Company or of any of its subsidiaries.
"Subsidiary" or "subsidiaries" shall be as defined in Section 424 of the Code
and the Treasury Regulations promulgated thereunder (the "Regulations").

        The Committee shall, from time to time, at its sole discretion, select
from such eligible individuals those to whom options shall be granted and shall
determine the number of shares to be subject to each option. In determining the
eligibility of an individual to be granted an option, as well as in determining
the number of shares to be granted to any individual, the Committee in its sole
discretion shall take into account the position and responsibilities of the
individual being considered, the nature and value to the Company or its
subsidiaries of his or her service and accomplishments, his or her present and
potential contribution to the success of the Company or its subsidiaries, and
such other factors as the Committee may deem relevant.


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        No option designated as an incentive stock option shall be granted to
any employee of the Company or any subsidiary if such employee owns, immediately
prior to the grant of an option, stock representing more than 10% of the voting
power or more than 10% of the value of all classes of stock of the Company or a
parent or a subsidiary, unless the purchase price for the stock under such
option shall be at least 110% of its fair market value at the time such option
is granted and the option, by its terms, shall not be exercisable more than five
years from the date it is granted. In determining the stock ownership under this
paragraph, the provisions of Section 424(d) of the Code shall be controlling. In
determining the fair market value under this paragraph, the provisions of
Section 7 hereof shall apply.

        6.     OPTION AGREEMENT.

        Each option shall be evidenced by an option agreement (the "Agreement")
duly executed on behalf of the Company and by the optionee to whom such option
is granted, which Agreement shall comply with and be subject to the terms and
conditions of the Plan. The Agreement may contain such other terms, provisions
and conditions which are not inconsistent with the Plan as may be determined by
the Committee, provided that options designated as incentive stock options shall
meet all of the conditions for incentive stock options as defined in Section 422
of the Code. The date of grant of an option shall be as determined by the
Committee. More than one option may be granted to an individual.

        7.     OPTION PRICE.

        The option price or prices of shares of the Company's Common Stock for
options designated as non-qualified stock options shall be determined by the
Committee, but in no event shall the option price of a non-qualified stock
option be less than the fair market value of such Common Stock at the time the
option is granted, as determined by the Committee. The option price or prices of
shares of


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the Company's Common Stock for incentive stock options shall be the fair market
value of such Common Stock at the time the option is granted as determined by
the Committee in accordance with the Regulations promulgated under Section 422
of the Code. If such shares are then listed on any national securities exchange,
the fair market value shall be the mean closing price on the largest such
exchange on the business day immediately preceding the date of the grant of the
option. If the shares are not then listed on any such exchange, the fair market
value of such shares shall be the mean closing price as reported in the National
Association of Securities Dealers Automated Quotation National Market
("NASDAQ/NM") for the business day immediately preceding the date of the grant
of the option. If the shares are not then either listed on any such exchange or
quoted in NASDAQ/NM, the fair market value shall be the mean between the average
of the "Bid" and the average of the "Ask" prices, if any, as reported in the
National Daily Quotation Service for the business day immediately preceding the
date of the grant of the option, or, if none, shall be determined by taking a
weighted average of the means between the highest and lowest sales prices on the
nearest date before and the nearest date after the date of grant in accordance
with Treasury Regulations Section 25.2512-2. If the fair market value cannot be
determined under the preceding three sentences, it shall be determined in good
faith by the Committee.

        8.     MANNER OF PAYMENT; MANNER OF EXERCISE.

        (a)    The payment of the exercise price, unless otherwise determined by
the Committee, shall be paid by delivery of (i) cash or a check payable to the
order of the Company in an amount equal to the exercise price of such options,
(ii) shares of Common Stock of the Company owned by the optionee having a fair
market value equal in amount to the exercise price of the options being
exercised, (iii) any combination of (i) and (ii), provided, however, that
payment of the exercise price by delivery of shares of Common Stock of the
Company owned by such optionee may be made only


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if such payment does not result in a charge to earnings for financial accounting
purposes as determined by the Committee, or (iv) payment may also be made by
delivery of a properly executed exercise notice to the Company, together with a
copy of irrevocable instruments to a broker to deliver promptly to the Company
the amount of sale or loan proceeds to pay the exercise price. The fair market
value of any shares of the Company's Common Stock which may be delivered upon
exercise of an option shall be determined by the Committee in accordance with
Section 7 hereof. To facilitate clause (iv) above, the Company may enter into
agreements for coordinated procedures with one or more brokerage firms. The date
of exercise shall be the date of delivery of such exercise notice.

        (b)    To the extent that the right to purchase shares under an option
has accrued and is in effect, options may be exercised in full at one time or in
part from time to time, by giving written notice, signed by the person or
persons exercising the option, to the Company, stating the number of shares with
respect to which the option is being exercised, accompanied by payment in full
for such shares as provided in subparagraph (a) above. Upon such exercise,
delivery of a certificate for paid-up non-assessable shares shall be made at the
principal office of the Company to the person or persons exercising the option
at such time, during ordinary business hours, after 9:00 a.m. but not more than
thirty (30) days from the date of receipt of the notice by the Company, as shall
be designated in such notice, or at such time, place and manner as may be agreed
upon by the Company and the person or persons exercising the option. Upon
exercise of the option and payment as provided above, the optionee shall become
a stockholder of the Company as to the Shares acquired upon such exercise.


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        9.     EXERCISE OF OPTIONS.

        (a)    Each option granted under the Plan shall, subject to Section
10(b) and Section 12 hereof, be exercisable with reference to the Vesting
Reference Date (the date selected by the Committee) as follows: prior to the
First Anniversary Date of the Vesting Reference Date -- zero percent (0%); on
the First Anniversary Date of the Vesting Reference Date -- twenty-five percent
(25%). Thereafter, additional shares shall vest equally on a monthly basis, in
arrears, such that by the Fourth Anniversary Date of the Vesting Reference Date
all shares shall vest, provided, however, that no option granted under the Plan
shall have a term in excess of ten (10) years from the date of grant.
Notwithstanding any other provisions of this section, in the event of the death
of the Participant, the Participant will automatically receive twelve (12)
months accelerated vesting under his or her Agreement or Stock Repurchase
Agreement, if applicable, as provided in Section 9(b).

        To the extent that an option to purchase shares is not exercised by an
optionee when it becomes initially exercisable, it shall not expire but shall be
carried forward and shall be exercisable, on a cumulative basis, until the
expiration of the exercise period. No partial exercise may be made for less than
fifty (50) full shares of Common Stock, unless the option is exercisable for
less than fifty (50) shares of Common Stock.

        (b)    Notwithstanding the foregoing, the Agreement may provide that the
option shall be immediately exercisable by the optionee provided that the
optionee enters into a Stock Repurchase Agreement approved by the Committee
which provides for a reverse vesting schedule in substance similar to that set
forth in Section 9(a) hereof, such unvested shares being held either in escrow
or otherwise by the Secretary or Treasurer of the Company until vested.


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        (c)    Notwithstanding the foregoing, the Committee may in its
discretion (i) specifically provide for another time or times of exercise or
(ii) accelerate the exercisability of any option subject to such terms and
conditions as the Committee deems necessary and appropriate.

        10.    TERM OF OPTIONS; EXERCISABILITY.

        (a)    Term.

               (1)    Each option shall expire not more than ten (10) years from
the date of the granting thereof, but shall be subject to earlier termination as
herein provided.

               (2)    Except as otherwise provided in this Section 10, an option
granted to any employee optionee who ceases to be an employee of the Company or
one of its subsidiaries shall terminate thirty (30) days after the date such
optionee ceases to be an employee of the Company or one of its subsidiaries, or
on the date on which the option expires by its terms, whichever occurs first.

               (3)    If such termination of employment is because of dismissal
for cause or because the employee is in breach of any employment agreement, such
option will terminate on the date the optionee ceases to be an employee of the
Company or one of its subsidiaries.

               (4)    If such termination of employment is because the optionee
has become permanently disabled (within the meaning of Section 22(e)(3) of the
Code), such option shall terminate on the last day of the sixth month from the
date such optionee ceases to be an employee, or on the date on which the option
expires by its terms, whichever occurs first.

               (5)    In the event of the death of any optionee, any option
granted to such optionee shall terminate on the last day of the sixth month from
the date of death, or on the date on which the option expires by its terms,
whichever occurs first.


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               (6)    Notwithstanding subparagraphs (2), (3), (4) and (5) above,
the Committee shall have the authority to extend the expiration date of any
outstanding option in circumstances in which it deems such action to be
appropriate.

        (b)    Exercisability. An option granted to an employee optionee who
ceases to be an employee of the Company or one of its subsidiaries, whether by
having become permanently disabled, as defined in Section 22(e)(3) of the Code,
by death, or otherwise, shall be exercisable only to the extent that the right
to purchase shares under such option has accrued and is in effect on the date
such optionee ceases to be an employee of the Company or one of its
subsidiaries. Options granted to non-employees shall have such exercisability
standards as the Committee shall determine.

        (c)    Stockholders' Agreement. Upon exercise by the Participant, such
Participant shall enter into a Stockholders' Agreement, such agreement to be on
such further terms and conditions as is determined by the Committee.

        11.    OPTIONS NOT TRANSFERABLE.

        The right of any optionee to exercise any option granted to him or her
shall not be assignable or transferable by such optionee otherwise than by will
or the laws of descent and distribution or as otherwise required by statute and
any such option shall be exercisable during the lifetime of such optionee only
by him. Any option granted under the Plan shall be null and void and without
effect upon the bankruptcy of the optionee to whom the option is granted, or
upon any attempted assignment or transfer, except as herein provided, including
without limitation any purported assignment, whether voluntary or by operation
of law, pledge, hypothecation or other disposition, attachment, divorce, trustee
process or similar process, whether legal or equitable, of such option.

        12.    RECAPITALIZATIONS, REORGANIZATIONS AND THE LIKE.


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        (a)    In the event that the outstanding shares of the Common Stock of
the Company are changed into or exchanged for a different number or kind of
shares or other securities of the Company or of another corporation by reason of
any reorganization, merger, consolidation, recapitalization, reclassification,
stock split-up, combination of shares, or dividends payable in capital stock,
appropriate adjustment shall be made in the number and kind of shares as to
which options may be granted under the Plan and as to which outstanding options
or portions thereof then unexercised shall be exercisable, to the end that the
proportionate interest of the optionee shall be maintained as before the
occurrence of such event; such adjustment in outstanding options shall be made
without change in the total price applicable to the unexercised portion of such
options and with a corresponding adjustment in the option price per share.

        (b)    In addition, unless otherwise determined by the Committee in its
sole discretion, in the case of any Change of Control (as hereinafter defined)
of the Company, the purchaser(s) of the Company's assets or stock may, in his,
her or its discretion, deliver to the optionee the same kind of consideration
that is delivered to the stockholders of the Company as a result of such sale,
conveyance or Change of Control, or the Committee may cancel all outstanding
options in exchange for consideration in cash or in kind, which consideration in
both cases shall be equal in value to those shares of stock or other securities
the optionee would have received had the option been exercised (to the extent
then exercisable) and no disposition of the shares acquired upon such exercise
been made prior to such Change of Control, less the option price therefor. Upon
receipt of consideration by the optionee, his or her option shall immediately
terminate and be of no further force and effect. The value of the stock or other
securities the optionee would have received if the option had been exercised
shall be determined in good faith by the Committee, and in the case of shares of
the Common Stock of the Company, in accordance with the provisions of Section 7
hereof. The Committee shall also have the power and right to accelerate the
exercisability of any options,


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notwithstanding any limitations in this Plan or in the Agreement upon such
Change of Control. A "Change of Control" shall be deemed to have occurred if any
of the following conditions have occurred: (1) the merger or consolidation of
the Company with another entity where the Company is not the surviving entity
and where after the merger or consolidation (i) its stockholders prior to the
merger or consolidation hold less than 50% of the voting stock of the surviving
entity and (ii) its directors prior to the merger or consolidation are less than
a majority of the Board of Directors of the surviving entity; (2) the sale of
all or substantially all of the Company's assets to a third party and subsequent
to the transaction (i) its stockholders hold less than 50% of the voting stock
of said third party and (ii) its directors are less than a majority of the Board
of Directors of said third party; or (3) a transaction or series of related
transactions, including a merger of the Company with another entity where the
Company is the surviving entity, whereby (i) 50% or more of the voting stock of
the Company after the transaction(s) is owned actually or beneficially by
parties who held less than thirty percent (30% ) of the voting stock, actually
or beneficially, prior to the transaction(s) and (ii) the Board of Directors
after the transaction(s) or within sixty (60) days thereof, is comprised of less
than a majority of the directors serving prior to the transaction(s).

        (c)    No fraction of a share shall be purchasable or deliverable upon
the exercise of any option, but in the event any adjustment hereunder of the
number of shares covered by the option shall cause such number to include a
fraction of a share, such fraction shall be adjusted to the nearest smaller
whole number of shares.

        13.    NO SPECIAL EMPLOYMENT RIGHTS -- LEAVES OF ABSENCE.

        Nothing contained in the Plan or in any option granted under the Plan
shall confer upon any option holder any right with respect to the continuation
of his or her employment by the Company (or any subsidiary thereof) or interfere
in any way with the right of the Company (or any subsidiary thereof), subject to
the terms of any separate employment agreement to the contrary, at any time to


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terminate such employment or to increase or decrease the compensation of the
option holder from the rate in existence at the time of the grant of an option.
Whether an authorized leave of absence, or absence in military or government
service, shall constitute termination of employment shall be determined by the
Committee at the time.

        14.    WITHHOLDING.

        The Company's obligation to deliver shares upon the exercise of any
option granted under the Plan shall be subject to the option holder's
satisfaction of all applicable Federal, state and local income, excise,
employment and any other tax withholding requirements.

        15.    RESTRICTIONS ON ISSUE OF SHARES.

        (a)    Notwithstanding the provisions of Section 8, the Company may
delay the issuance of shares covered by the exercise of an option and the
delivery of a certificate for such shares until one of the following conditions
shall be satisfied:

                   (1) The shares with respect to which such option has been
exercised are at the time of the issue of such shares effectively registered or
qualified under applicable Federal and state securities acts now in force or as
hereafter amended; or

                   (2) Counsel for the Company shall have given an opinion,
which opinion shall not be unreasonably conditioned or withheld, that such
shares are exempt from registration and qualification under applicable Federal
and state securities acts now in force or as hereafter amended.

        (b)    It is intended that all exercises of options shall be effective,
and the Company shall use its best efforts to bring about compliance with the
above conditions within a reasonable time, except that the Company shall be
under no obligation to qualify shares or to cause a registration statement or a
post-effective amendment to any registration statement to be prepared for the
purpose


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of covering the issue of shares in respect of which any option may be exercised,
except as otherwise agreed to by the Company in writing.

        16.    PURCHASE FOR INVESTMENT; RIGHTS OF HOLDER ON SUBSEQUENT
REGISTRATION.

        Unless the shares to be issued upon exercise of an option granted under
the Plan have been effectively registered under the Securities Act of 1933, as
now in force or hereafter amended, the Company shall be under no obligation to
issue any shares covered by any option unless the person who exercises such
option, in whole or in part, shall give a written representation and undertaking
to the Company which is satisfactory in form and scope to counsel for the
Company and upon which, in the opinion of such counsel, the Company may
reasonably rely, that he or she is acquiring the shares issued pursuant to such
exercise of the option for his or her own account as an investment and not with
a view to, or for sale in connection with, the distribution of any such shares,
and that he or she will make no transfer of the same except in compliance with
any rules and regulations in force at the time of such transfer under the
Securities Act of 1933, or any other applicable law, and that if shares are
issued without such registration, a legend to this effect may be endorsed upon
the securities so issued. In the event that the Company shall, nevertheless,
deem it necessary or desirable to register under the Securities Act of 1933 or
other applicable statutes any shares with respect to which an option shall have
been exercised, or to qualify any such shares for exemption from the Securities
Act of 1933 or other applicable statutes, then the Company may take such action
and may require from each optionee such information in writing for use in any
registration statement, supplementary registration statement, prospectus,
preliminary prospectus or offering circular as is reasonably necessary for such
purpose and may require reasonable indemnity to the Company and its officers and
directors and controlling persons from such holder against all losses, claims,
damages and liabilities arising from such use of the information so furnished
and caused by


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any untrue statement of any material fact therein or caused by the omission to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading in the light of the circumstances under which
they were made.

        17.    LOANS.

        The Company may make loans to optionees to permit them to exercise
options. If loans are made, the requirements of all applicable Federal and state
laws and regulations regarding such loans must be met and the stock issued
pursuant to the exercise of such option shall be pledged to the Company pursuant
to a Stock Pledge Agreement as security for the loan until such amounts are
repaid.

        18.    MODIFICATION OF OUTSTANDING OPTIONS.

        The Committee may authorize the amendment of any outstanding option with
the consent of the optionee when and subject to such conditions as are deemed to
be in the best interests of the Company and in accordance with the purposes of
this Plan.

        19.    APPROVAL OF STOCKHOLDERS.

        The Plan shall be subject to approval by the vote of stockholders
holding at least a majority of the voting stock of the Company present, or
represented, and entitled to vote at a duly held stockholders' meeting, or by
written consent of the stockholders as provided for under applicable state law,
within twelve (12) months after the adoption of the Plan by the Board of
Directors and shall take effect as of the date of adoption by the Board of
Directors upon such approval. The Committee may grant options under the Plan
prior to such approval, but any such option shall become effective as of the
date of grant only upon such approval and, accordingly, no such option may be
exercisable prior to such approval.


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        20.    TERMINATION AND AMENDMENT.

        Unless sooner terminated as herein provided, the Plan shall terminate
ten (10) years from the date upon which the Plan was duly adopted by the Board
of Directors of the Company. The Board of Directors may at any time terminate
the Plan or make such modification or amendment thereof as it deems advisable;
provided, however, that except as provided in this Section 20, the Board of
Directors may not, without the approval of the stockholders of the Company
obtained in the manner stated in Section 19, increase the maximum number of
shares for which options may be granted or change the designation of the class
of persons eligible to receive options under the Plan, or make any other change
in the Plan which requires stockholder approval under applicable law or
regulations, including any approval requirement which is a prerequisite for
exemptive relief under Section 16 of the 1934 Act. The Committee may terminate,
amend or modify any outstanding option without the consent of the option holder,
provided, however, that, except as provided in Section 12, without the consent
of the optionee, the Committee shall not change the number of shares subject to
an option, nor the exercise price thereof, nor extend the term of such option.

        21.    RESERVATION OF STOCK.

        The Company shall at all times during the term of the Plan reserve and
keep available such number of shares of stock as will be sufficient to satisfy
the requirements of the Plan and shall pay all fees and expenses necessarily
incurred by the Company in connection therewith.



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        22.    LIMITATION OF RIGHTS IN THE OPTION SHARES.

        An optionee shall not be deemed for any purpose to be a stockholder of
the Company with respect to any of the options except to the extent that the
option shall have been exercised with respect thereto and, in addition, a
certificate shall have been issued theretofore and delivered to the optionee.

        23.    NOTICES.

        Any communication or notice required or permitted to be given under the
Plan shall be in writing, and mailed by registered or certified mail or
delivered by hand, if to the Company, to its principal place of business,
attention: President, and, if to an optionee, to the address as appearing on the
records of the Company.


        APPROVED BY THE BOARD:  January 11, 2001
                                ----------------

        APPROVED BY STOCKHOLDERS:  January 11, 2001
                                   ----------------

        AMENDMENT APPROVED BY THE BOARD:  October 25, 2002
                                          ----------------

        AMENDMENT APPROVED BY STOCKHOLDERS:  November 11, 2002
                                             -----------------




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