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                                                                   EXHIBIT 10.25

                       REDBACK NETWORKS INC. 2001 NON PLAN

                          NOTICE OF STOCK OPTION GRANT

             You have been granted the following option to purchase Common Stock
of Redback Networks Inc. (the "Company"):

<TABLE>
<CAPTION>

<S>               <C>                                         <C>
                  Name of Optionee:                           Georges Antoun

                  Total Number of Shares Granted:             1,000,000

                  Type of Option:                             Nonstatutory Stock Option

                  Exercise Price Per Share:                   $ 4.17

                  Date of Grant:                              August 29, 2001

                  Date Exercisable:                           This option may be exercised, in accordance with the
                                                              vesting schedule.

                  Vesting Commencement Date:                  August 29, 2001

                  Vesting Schedule:

                                                              This option shall become exercisable with respect to
                                                              options to purchase the first 25% the Shares when
                                                              you complete 12 months of continuous service with
                                                              the Company or a subsidiary of the Company from
                                                              the vesting commencement date and with respect to
                                                              an additional 2.0833% of the Shares subject to this
                                                              option when you complete each month of continuous
                                                              service thereafter.

                  Expiration Date:                            August 29, 2011
</TABLE>

In the event a Change in Control occurs (as defined in the attached Stock Option
Agreement) before your employment terminates and (1) your service with the
Company or a subsidiary of the Company is terminated by the Company or its
successor without Cause or (2) your scope of responsibilities are materially
reduced or (3) you're your salary is reduced (other than in a Company wide
reduction in salary) then your stock option granted hereunder will immediately
be fully vested and exercisable with respect to all shares. For purposes of the
forgoing, Cause shall mean: (1) any breach of the Proprietary Information and
Inventions Agreement between you and the Company or any other written agreement
between you and the Company if such breach causes material harm to the Company;
(2) any willful misconduct that causes material harm to the Company, including
without limitation repeated failure to follow the directions of the person to
whom you report; (3) conviction of, or plea of guilty or no contest to a felony
under the laws of the US or any state thereof; (4) misappropriation of any
assets of the Company or any other acts of Fraud or embezzlement; or the abuse
of alcohol or controlled substances that has a detrimental effect upon your
performance of duties for the Company.

By your signature and the signature of the Company's representative below, you
and the Company agree that this option is granted under and governed by the
terms and conditions of the Stock Option Agreement, which is attached to and
made a part of this document.

OPTIONEE:                            REDBACK NETWORKS INC.

/s/ Georges Antoun                   By: /s/ Kevin A DeNuccio
--------------------------               -------------------------------------



                                    Title: Chief Executive Officer and President
                                           ------------------------------------


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                       REDBACK NETWORKS INC. 2001 NON-PLAN

                             STOCK OPTION AGREEMENT

Tax Treatment       This  option is  intended to be a  nonstatutory
                    option,  as provided in the Notice of Stock Option
                    Grant.

Vesting             This option becomes exercisable in installments, as
                    shown in the Notice of Stock Option Grant.

                    In addition, this option becomes exercisable in
                    full if your service as an employee, consultant or
                    director of the Company or a subsidiary of the
                    Company terminates because of death. If your
                    service as an employee, consultant or director of
                    the Company (or a subsidiary of the Company)
                    terminates because of total and permanent
                    disability, then the exercisable portion of this
                    option will be determined by adding 12 months to
                    your actual period of service.

                    Except for the acceleration provisions specified in
                    the grant, no additional shares become exercisable
                    after your service as an employee, consultant or
                    director of the Company or a subsidiary of the
                    Company has terminated for any reason.

Term                This option expires in any event at the close of
                    business at Company headquarters on the day before
                    the 10th anniversary of the Date of Grant, as shown
                    in the Notice of Stock Option Grant. (It will
                    expire earlier if your service terminates, as
                    described below.)

Regular             If your service as an employee,
Termination         consultant or director of the Company or a
                    subsidiary of the Company terminates for any reason
                    except death or total and permanent disability,
                    then this option will expire at the close of
                    business at Company headquarters on the date three
                    months after your termination date. The Company
                    determines when your service terminates for this
                    purpose.

Death               If you die as an employee, consultant or director
                    of the Company or a subsidiary of the Company, then
                    this option will expire at the close of business at
                    Company headquarters on the date 12 months after
                    the date of death.



Disability          If your service as an employee, consultant or
                    director of the Company or a subsidiary of the
                    Company terminates because of your total and
                    permanent disability, then this option will expire
                    at the close of business at Company headquarters on
                    the date six months after your termination date.

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                    For all purposes under this Agreement, "total and permanent
                    disability" means that you are unable to engage in any
                    substantial gainful activity by reason of any medically
                    determinable physical or mental impairment which can be
                    expected to result in death or which has lasted, or can be
                    expected to last, for a continuous period of not less than
                    one year.

Leaves of Absence   For purposes of this option, your service does not terminate
                    when you go on a military leave, a sick leave or another
                    bona fide leave of absence, if the leave was approved by the
                    Company in writing and if continued crediting of service is
                    required by the terms of the leave or by applicable law. But
                    your service terminates when the approved leave ends, unless
                    you immediately return to active work.

Restrictions on     The Company will not permit you to exercise this option
  Exercise          if the issuance of shares at that time would violate
                    any law or regulation.

Notice of Exercise  When you wish to exercise this option, you must notify the
                    Company by filing the proper "Notice of Exercise" form at
                    the address given on the form. Your notice must specify how
                    many shares you wish to purchase. Your notice must also
                    specify how your shares should be registered (in your name
                    only or in your and your spouse's names as community
                    property or as joint tenants with right of survivorship).
                    The notice will be effective when it is received by the
                    Company.

                    If someone else wants to exercise this option after your
                    death, that person must prove to the Company's satisfaction
                    that he or she is entitled to do so.

 Form of Payment    When you submit your notice of exercise, you must include
                    payment of the option exercise price for the shares you are
                    purchasing. Payment may be made in one (or a combination of
                    two or more) of the following forms:

                    .  Your personal check, a cashier's check or a money order.

                    .  Certificates for shares of Company stock that you own,
                       along with any forms needed to effect a transfer of those
                       shares to the Company. The value of the shares,
                       determined as of the effective date of the option
                       exercise, will be applied to the option exercise price.
                       Instead of surrendering shares of Company stock, you may
                       attest to the ownership of those shares on a form
                       provided by the Company and have the same number of
                       shares subtracted from the option shares issued to you.
                       However, you may not surrender, or attest to the
                       ownership of, shares of Company stock in payment of the
                       exercise price if your action would cause the Company to
                       recognize compensation expense (or additional
                       compensation expense) with respect to this option for
                       financial reporting purposes.

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                    .    Irrevocable directions to a securities broker approved
                         by the Company to sell all or part of your option
                         shares and to deliver to the Company from the sale
                         proceeds an amount sufficient to pay the option
                         exercise price and any withholding taxes. (The balance
                         of the sale proceeds, if any, will be delivered to
                         you.) The directions must be given by signing a special
                         "Notice of Exercise" form provided by the Company.

                    .    Irrevocable directions to a securities broker or lender
                         approved by the Company to pledge option shares as
                         security for a loan and to deliver to the Company from
                         the loan proceeds an amount sufficient to pay the
                         option exercise price and any withholding taxes. The
                         directions must be given by signing a special "Notice
                         of Exercise" form provided by the Company.

Withholding
Taxes and           You will not be allowed to exercise this option unless you
Stock Withholding   make arrangements acceptable to the Company to pay any
                    withholding taxes that may be due as a result of the option
                    exercise. These arrangements may include withholding shares
                    of Company stock that otherwise would be issued to you when
                    you exercise this option. The value of these shares,
                    determined as of the effective date of the option exercise,
                    will be applied to the withholding taxes.

Restrictions on     By signing this Agreement, you agree not to sell any option
Resale              shares at a time when applicable laws, Company policies or
                    an agreement between the Company and its underwriters
                    prohibit a sale. This restriction will apply as long as you
                    are an employee, consultant or director of the Company or a
                    subsidiary of the Company.

Transfer of Option  Prior to your death, only you may exercise this option. You
                    cannot transfer or assign this option. For instance, you may
                    not sell this option or use it as security for a loan. If
                    you attempt to do any of these things, this option will
                    immediately become invalid. You may, however, dispose of
                    this option in your will or a beneficiary designation.

                    Regardless of any marital property settlement agreement, the
                    Company is not obligated to honor a notice of exercise from
                    your former spouse, nor is the Company obligated to
                    recognize your former spouse's interest in your option in
                    any other way.

Retention Rights    Neither your option nor this Agreement give you the right to
                    be retained by the Company or a subsidiary of the Company in
                    any capacity. The Company and its subsidiaries reserve the
                    right to terminate your service at any time, with or without
                    cause.


Committee           This Agreement shall be  administered  by the Committee. The
                    Committee shall consist exclusively of two or more directors
                    of the Company, who shall be appointed by the Board. In
                    addition, the composition of the Committee shall satisfy:

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                         (a) Such requirements as the Securities and Exchange
                    Commission may establish for administrators acting under
                    plans intended to qualify for exemption under Rule 16b-3 (or
                    its successor) under the Exchange Act; and

                         (b) Such requirements as the Internal Revenue Service
                    may establish for outside directors acting under plans
                    intended to qualify for exemption under section 162(m)(4)(C)
                    of the Code.

               The Committee shall interpret the Agreement. The Committee's
               determinations under this Agreement made in good faith shall be
               final and binding on all persons.

Stockholder    You, or your estate or heirs, have no rights as a stockholder of
Rights         the Company until you have exercised this option by giving the
               required notice to the Company and paying the exercise price. No
               adjustments are made for dividends or other rights if the
               applicable record date occurs before you exercise this option,
               except as described below.

 Adjustments   In the event of a subdivision of the outstanding Common Shares, a
               declaration of a dividend payable in Common Shares, a declaration
               of a dividend payable in a form other than Common Shares in an
               amount that has a material effect on the price of Common Shares,
               a combination or consolidation of the outstanding Common Shares
               (by reclassification or otherwise) into a lesser number of Common
               Shares, a recapitalization, a spin-off or a similar occurrence,
               the Committee shall make such adjustments as it, in its sole
               discretion, deems appropriate in one or more of (a) the number of
               Common Shares covered by each outstanding Option or (b) the
               Exercise Price under each outstanding Option. Except as provided
               in this paragraph, an Optionee no rights by reason of any issue
               by the Company of stock of any class or securities convertible
               into stock of any class, any subdivision or consolidation of
               shares of stock of any class, the payment of any stock dividend
               or any other increase or decrease in the number of shares of
               stock of any class. To the extent not previously exercised,
               Options shall terminate immediately prior to the dissolution or
               liquidation of the Company.

               In the event that the Company is a party to a merger or other
               reorganization, outstanding Options and Restricted Shares shall
               be subject to the agreement of merger or reorganization. Such
               agreement shall provide for (a) the continuation of the
               outstanding Awards by the Company, if the Company is a surviving
               corporation, (b) the assumption of the outstanding Awards by the
               surviving corporation or its parent or subsidiary, (c) the
               substitution by the surviving corporation or its parent

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                    or subsidiary of its own awards for the outstanding Awards,
                    (d) full exercisability or vesting and accelerated
                    expiration of the outstanding Awards or (e) settlement of
                    the full value of the outstanding Awards in cash or cash
                    equivalents followed by cancellation of such Awards.

                    Within the limitations of this Agreement, the Committee may
                    modify, extend or assume outstanding options or may accept
                    the cancellation of outstanding options (whether granted by
                    the Company or by another issuer) in return for the grant of
                    new options for the same or a different number of shares and
                    at the same or a different exercise price. The foregoing
                    notwithstanding, no modification of an Option shall, without
                    the consent of the Optionee, alter or impair his or her
                    rights or obligations under such Option. The Committee may
                    at any time (a) offer to buy out for a payment in cash or
                    cash equivalents an Option previously granted or (b)
                    authorize an Optionee to elect to cash out an Option
                    previously granted, in either case at such time and based
                    upon such terms and conditions as the Committee shall
                    establish.

Deferral of         The Committee (in its sole discretion) may permit or require
Delivery of Shares  an Optionee to have Common Shares that otherwise would be
                    delivered to such Optionee as a result of the exercise of an
                    Option converted into amounts credited to a deferred
                    compensation account established for such Optionee by the
                    Committee as an entry on the Company's books. Such amounts
                    shall be determined by reference to the Fair Market Value of
                    such Common Shares as of the date when they otherwise would
                    have been delivered to such Optionee. A deferred
                    compensation account established under this paragraph may be
                    credited with interest or other forms of investment return,
                    as determined by the Committee. An Optionee for whom such an
                    account is established shall have no rights other than those
                    of a general creditor of the Company. Such an account shall
                    represent an unfunded and unsecured obligation of the
                    Company and shall be subject to the terms and conditions of
                    the applicable agreement between such Optionee and the
                    Company. If the conversion of Options is permitted or
                    required, the Committee (in its sole discretion) may
                    establish rules, procedures and forms pertaining to such
                    conversion, including (without limitation) the settlement of
                    deferred compensation accounts established under this
                    paragraph.

                    .    "Affiliate" means any entity other than a Subsidiary,
                         if the Company and/or one or more Subsidiaries own not
                         less than 50% of such entity.

                    .    "Award" means any award of an Option or a Restricted
                         Share under the Plan.

                    .    "Board" means the Company's Board of Directors, as
                         constituted from time to time.

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               .    "Change in Control" shall mean:

                         (a) The consummation of a merger or consolidation of
                    the Company with or into another entity or any other
                    corporate reorganization, if persons who were not
                    stockholders of the Company immediately prior to such
                    merger, consolidation or other reorganization own
                    immediately after such merger, consolidation or other
                    reorganization 50% or more of the voting power of the
                    outstanding securities of each of (i) the continuing or
                    surviving entity and (ii) any direct or indirect parent
                    corporation of such continuing or surviving entity;

                         (b) The sale, transfer or other disposition of all or
                    substantially all of the Company's assets;

                         (c) A change in the composition of the Board, as a
                    result of which 50% or fewer of the incumbent directors are
                    directors who either (i) had been directors of the Company
                    on the date 24 months prior to the date of the event that
                    may constitute a Change in Control (the "original
                    directors") or (ii) were elected, or nominated for election,
                    to the Board with the affirmative votes of at least a
                    majority of the aggregate of the original directors who were
                    still in office at the time of the election or nomination
                    and the directors whose election or nomination was
                    previously so approved; or

                         (d) Any transaction as a result of which any person is
                    the "beneficial owner" (as defined in Rule 13d-3 under the
                    Exchange Act), directly or indirectly, of securities of the
                    Company representing at least 50% of the total voting power
                    represented by the Company's then outstanding voting
                    securities. For purposes of this Subsection (d), the term
                    "person" shall have the same meaning as when used in
                    sections 13(d) and 14(d) of the Exchange Act but shall
                    exclude (i) a trustee or other fiduciary holding securities
                    under an employee benefit plan of the Company or of a Parent
                    or Subsidiary and (ii) a corporation owned directly or
                    indirectly by Definitions the stockholders of the Company in
                    substantially the same proportions as their ownership of the
                    common stock of the Company.

               A transaction shall not constitute a Change in Control if its
               sole purpose is to change the state of the Company's
               incorporation or to create a holding company that will be owned
               in substantially the same

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          proportions by the persons who held the Company's securities
          immediately before such transaction.

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

          .    "Committee" means a committee of the Board, as described in
               Article 2.

          .    "Common Share" means one share of the common stock of the
               Company.

          .    "Company" means Redback Networks Inc., a Delaware corporation.

          .    "Consultant" means a consultant or adviser who provides bona fide
               services to the Company, a Parent, a Subsidiary or an Affiliate
               as an independent contractor. Service as a Consultant shall be
               considered employment for all purposes of this Stock Option
               Agreement.

          .    "Employee" means a common-law employee of the Company, a Parent,
               a Subsidiary or an Affiliate.

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

          .    "Exercise Price" means the amount for which one Common Share may
               be purchased upon exercise of such Option, as specified in the
               applicable Stock Option Agreement.

          .    "Fair Market Value" means the market price of Common Shares,
               determined by the Committee in good faith on such asis as it
               deems appropriate. Whenever possible, the determination of Fair
               Market Value by the Committee shall be based on the prices
               reported in The Wall Street Journal. Such determination shall be
                           -----------------------
               conclusive and binding on all persons.

          .    "NSO" means a stock option not described in sections 422 or 423
               of the Code.

          .    "Option" means an NSO granted under this Agreement and entitling
               the holder to purchase Common Shares.

          .    "Optionee" means an individual or estate who holds an Option.

          .    "Outside Director" shall mean a member of the Board

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               who is not an Employee.


          .    "Parent" means any corporation (other than the Company) in an
               unbroken chain of corporations ending with the Company, if each
               of the corporations other than the Company owns stock possessing
               50% or more of the total combined voting power of all classes of
               stock in one of the other corporations in such chain. A
               corporation that attains the status of a Parent on a date after
               the adoption of the Plan shall be considered a Parent commencing
               as of such date agreement between the Company and an Optionee
               that contains the terms, conditions and restrictions pertaining
               to his or her Option.

          .    "Subsidiary" means any corporation (other than the Company) in an
               unbroken chain of corporations beginning with the Company, if
               each of the corporations other than the last corporation in the
               unbroken chain owns stock possessing 50% or more of the total
               combined voting power of all classes of stock in one of the other
               corporations in such chain.

Applicable     This Agreement will be interpreted and enforced under the
Law            laws of the State of Delaware (without regard to their
               choice-of-law provisions).

The Plan and
Other
Agreements     This Agreement constitutes the entire understanding between you
               and the Company regarding this option. Any prior agreements,
               commitments or negotiations concerning this option are
               superseded. This Agreement may be amended only by another written
               agreement, signed by both parties.

      BY SIGNING THE COVER SHEET OF THIS AGREEMENT, YOU AGREE TO ALL OF THE
             TERMS AND CONDITIONS DESCRIBED ABOVE AND IN THE PLAN.

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