<PAGE>   1

          As filed with the Securities and Exchange Commission on March 15, 2000
                                                          Registration No.  333-
================================================================================


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT

                                      Under
                           The Securities Act of 1933

                             REDBACK NETWORKS, INC.
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                               <C>                             <C>
            DELAWARE                          3576                     77-0438443
(State or other jurisdiction of   (Primary Standard Industrial       (IRS Employer
 incorporation or organization)    Classification Code Number)    Identification No.)
</TABLE>

                             1389 MOFFET PARK DRIVE
                           SUNNYVALE, CALIFORNIA 94089
               (Address of principal executive offices) (Zip Code)

                             REDBACK NETWORKS, INC.
                            1999 STOCK INCENTIVE PLAN
                       1999 EMPLOYEE STOCK PURCHASE PLAN
                           1999 DIRECTORS' OPTION PLAN
                 SIARA SYSTEMS, INC. 1998 EQUITY INCENTIVE PLAN

                            (Full title of the Plans)

                                DENNIS L. BARSEMA
                            CHIEF EXECUTIVE OFFICER
                             REDBACK NETWORKS, INC.
                             1389 MOFFET PARK DRIVE
                           SUNNYVALE, CALIFORNIA 94089
                     (Name and address of agent for service)

                                 (408) 548-3500
          (Telephone number, including area code, of agent for service)


<PAGE>   2

<TABLE>
<CAPTION>
                                         CALCULATION OF REGISTRATION FEE
==================================================================================================================
                                                             PROPOSED MAXIMUM    PROPOSED MAXIMUM       AMOUNT OF
                                          AMOUNT TO BE      OFFERING PRICE        AGGREGATE         REGISTRATION
TITLE OF SECURITIES TO BE REGISTERED      REGISTERED(1)       PER SHARE         OFFERING PRICE           FEE
------------------------------------      -------------    ----------------    ----------------     ------------
<S>                                       <C>               <C>                <C>                  <C>
1999 STOCK INCENTIVE PLAN

Options to Purchase Common Stock          5,194,846            N/A              N/A                  N/A

Common Stock, $0.0001 par value           5,194,846 shares     $357.50(3)       $1,857,157,445(3)    $490,289.57

1999 EMPLOYEE STOCK PURCHASE PLAN

Rights to purchase Common Stock           1,000,000            N/A              N/A                  N/A

Common Stock, $0.0001 par value           1,000,000 share      $357.50(3)       $  357,500,000(3)    $ 94,380.00

1999 DIRECTORS' OPTION PLAN

Options to purchase Common Stock          550,000              N/A              N/A                  N/A

Common Stock, $0.0001 par value           550,000 shares       $357.50(3)       $196,625,000(3)      $ 51,909.00

SIARA SYSTEMS, INC. 1998 EQUITY
INCENTIVE PLAN

Options to Purchase Common Stock          2,425,000            N/A              N/A                  N/A

Common Stock, $0.0001 par value           2,425,000 share      $0.86(2)         $  2,085,500(2)      $   550.57
=================================================================================================================
</TABLE>

(1)  This Registration Statement shall also cover any additional shares of
     Common Stock which become issuable under the 1999 Stock Incentive Plan, the
     1999 Employee Stock Purchase Plan, the 1999 Directors' Option Plan and the
     Siara Systems, Inc. 1998 Equity Incentive Plan by reason of any stock
     dividend, stock split, recapitalization or other similar transaction
     effected without the receipt of consideration which results in an increase
     in the number of the outstanding shares of Common Stock of Redback
     Networks, Inc.

(2)  Calculated solely for purposes of this offering under Rule 457(h) of the
     Securities Act of 1933, as amended, on the basis of the weighted average
     exercise price of the outstanding options.

(3)  Calculated solely for purposes of this offering under Rule 457(h) of the
     Securities Act of 1933, as amended, on the basis of the average of the high
     and low price per share of Common Stock of Redback Networks, Inc. as
     reported on the Nasdaq National Market on March 9, 2000.

<PAGE>   3

PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

     Redback Networks, Inc. (the "Registrant") hereby incorporates by reference
into this Registration Statement the following documents previously filed with
the Securities and Exchange Commission (the "SEC"):

     (a)  The Registrant's Annual Report on Form 10-K for the fiscal year ended
          December 31, 1999;

     (b)  The Registrant's Registration Statement No. 0-25853 on Form 8-A filed
          with the SEC on April 22, 1999, pursuant to Section 12 of the
          Securities Exchange Act of 1934, as amended (the "1934 Act"), in which
          there is described the terms, rights and provisions applicable to the
          Registrant's outstanding Common Stock.

     All reports and definitive proxy or information statements filed pursuant
to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act after the date of this
Registration Statement and prior to the filing of a post-effective amendment
which indicates that all securities offered hereby have been sold or which
deregisters all securities then remaining unsold shall be deemed to be
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filing of such documents. Any statement contained in a
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein or in any subsequently filed
document which also is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any such statement so modified or superseded shall
not be deemed, except as so modified or superseded, to constitute a part of this
Registration Statement.

Item 4. Description of Securities

     Not Applicable.

Item 5. Interests of Named Experts and Counsel

     Not Applicable.

Item 6. Indemnification of Directors and Officers

     Section 145 of the Delaware General Corporation Law authorizes a court to
award or a corporation's Board of Directors to grant indemnification to
directors and officers in terms sufficiently broad to permit such
indemnification under certain circumstances for liabilities (including
reimbursement for expenses incurred) arising under the Securities Act of 1933,
as amended (the "1933 Act"). The Registrant's Bylaws provide for mandatory
indemnification of its directors and officers and permissible indemnification of
employees and other agents to the maximum extent permitted by the Delaware
General Corporation Law. In addition, the Registrant has entered into
Indemnification Agreements with each of its directors and officers.

Item 7. Exemption from Registration Claimed

     Not Applicable.

Item 8. Exhibits

<TABLE>
<CAPTION>
Exhibit Number      Exhibit
--------------      -------
<S>                 <C>
     4              Instrument Defining Rights of Stockholders. Reference is made
                    to Registrant's Registration Statement No. 0-25853 on Form 8-A,
                    which is incorporated herein by reference pursuant to Item 3(p)
                    of this Registration Statement.

     5              Opinion and consent of Gunderson Dettmer Stough Villeneuve
                    Franklin & Hachigian, LLP.

    23.1            Consent of Independent Accountants.

    23.2            Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                    Hachigian, LLP is contained in Exhibit 5.

    24              Power of Attorney. Reference is made to page II-4 of this
                    Registration Statement.
</TABLE>


                                      II-1

<PAGE>   4

Item 9. Undertakings

     A.   The undersigned Registrant hereby undertakes: (1) to file, during any
period in which offers or sales are being made, a post-effective amendment to
this Registration Statement (i) to include any prospectus required by Section
10(a)(3) of the 1933 Act, (ii) to reflect in the prospectus any facts or events
arising after the effective date of this Registration Statement (or the most
recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in this
Registration Statement and (iii) to include any material information with
respect to the plan of distribution not previously disclosed in this
Registration Statement or any material change to such information in this
Registration Statement; provided, however, that clauses (1)(i) and (1)(ii) shall
not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into this Registration Statement; (2) that for the
purpose of determining any liability under the 1933 Act each such post-effective
amendment shall be deemed to be a new registration statement relating to the
securities offered therein and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof and (3) to remove
from registration by means of a post-effective amendment any of the securities
being registered which remain unsold at the termination of the Registrant's 1999
Stock Incentive Plan, the 1999 Employee Stock Purchase Plan, the 1999 Directors'
Option Plan and the Siara Systems, Inc. 1998 Equity Incentive Plan.

     B.   The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the 1933 Act, each filing of the Registrant's
annual report pursuant to Section 13(a) or Section 15(d) of the 1934 Act that is
incorporated by reference into this Registration Statement shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

     C.   Insofar as indemnification for liabilities arising under the 1933 Act
may be permitted to directors, officers or controlling persons of the Registrant
pursuant to the indemnification provisions summarized in Item 6 or otherwise,
the Registrant has been advised that, in the opinion of the SEC, such
indemnification is against public policy as expressed in the 1933 Act, and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred
or paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the 1933 Act and will be governed by the final
adjudication of such issue.


                                      II-2

<PAGE>   5

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8, and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Sunnyvale, State of California on this 15th
day of March, 2000.


                                        REDBACK NETWORKS, INC.


                                        By: /s/ Dennis L. Barsema
                                           -------------------------------------
                                           Dennis L. Barsema
                                           Chief Executive Officer




                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

     That the undersigned officers and directors of Redback Networks, Inc., a
Delaware corporation, do hereby constitute and appoint Dennis L. Barsema and
Craig M. Gentner, and either of them, the lawful attorneys-in-fact and agents
with full power and authority to do any and all acts and things and to execute
any and all instruments which said attorneys and agents, and either one of them,
determine may be necessary or advisable or required to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules or
regulations or requirements of the Securities and Exchange Commission in
connection with this Registration Statement. Without limiting the generality of
the foregoing power and authority, the powers granted include the power and
authority to sign the names of the undersigned officers and directors in the
capacities indicated below to this Registration Statement, to any and all
amendments, both pre-effective and post-effective, and supplements to this
Registration Statement, and to any and all instruments or documents filed as
part of or in conjunction with this Registration Statement or amendments or
supplements thereof, and either of the undersigned hereby ratifies and confirms
all that said attorneys and agents, or either one of them, shall do or cause to
be done by virtue hereof. This Power of Attorney may be signed in several
counterparts.

     IN WITNESS WHEREOF, each of the undersigned has executed this Power of
Attorney as of the date indicated.

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed below by the following persons in
the capacities and on the dates indicated.

<TABLE>
<CAPTION>
            Signature                            Title                           Date
            ---------                            -----                           ----
<S>                                <C>                                       <C>
/s/ Dennis L. Barsema              Chief Executive Officer                   March 15, 2000
--------------------------------   and Director (Principal Executive
Dennis L. Barsema                  Officer)


/s/ Craig M. Gentner               Senior Vice President of Finance,         March 15, 2000
--------------------------------   Chief Financial Officer and
Craig M. Gentner                   Corporate Secretary


/s/ James R. Flach                 Director                                  March 14, 2000
--------------------------------
James R. Flach


                                   Director
--------------------------------
Promod Haque


                                   Director
--------------------------------
Vinod Khosla


/s/ William Kurtz                  Director                                  March 14, 2000
--------------------------------
William Kurtz


/s/ Pierre R. Lamond               Director                                  March 14, 2000
--------------------------------
Pierre R. Lamond


/s/ Vivek Ragavan                  President, Chief Operating                March 14, 2000
--------------------------------   Officer and Director
Vivek Ragavan


/s/ Daniel J. Warmenhoven          Director                                  March 14, 2000
--------------------------------
Daniel J. Warmenhoven


</TABLE>


                                      II-3

<PAGE>   6

                       SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.



                                    EXHIBITS

                                       TO

                                    FORM S-8

                                      UNDER

                             SECURITIES ACT OF 1933



                             REDBACK NETWORKS, INC.


<PAGE>   7

                                  EXHIBIT INDEX

<TABLE>
<CAPTION>
Exhibit Number      Exhibit
--------------      -------
<S>                 <C>
     4              Instrument Defining Rights of Stockholders. Reference is made
                    to Registrant's Registration Statement No. 0-25853 on Form 8-A,
                    which is incorporated herein by reference pursuant to Item 3(p)
                    of this Registration Statement.

     5              Opinion and consent of Gunderson Dettmer Stough Villeneuve
                    Franklin & Hachigian, LLP.

    23.1            Consent of Independent Accountants.

    23.2            Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                    Hachigian, LLP is contained in Exhibit 5.

    24              Power of Attorney. Reference is made to page II-4 of this
                    Registration Statement.
</TABLE>
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 17786}]
{"company-data": {"conformed-name": "REDBACK NETWORKS INC", "cik": "0001081290", "assigned-sic": "7389", "irs-number": "770438443", "state-of-incorporation": "DE"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-32554", "film-number": "570651"}, "business-address": {"street1": "1389 MOFFETT PARK DR", "city": "SUNNYVALE", "state": "CA", "zip": "94089", "phone": "4085483500"}, "mail-address": {"street1": "1389 MOFFETT PARK DR", "city": "SUNNYVALE", "state": "CA", "zip": "94089"}}
1

          As filed with the Securities and Exchange Commission on March 15, 2000
                                                          Registration No.  333-
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT

                                      Under
                           The Securities Act of 1933

                             REDBACK NETWORKS, INC.
             (Exact name of registrant as specified in its charter)
DELAWARE                          3576                     77-0438443
(State or other jurisdiction of   (Primary Standard Industrial       (IRS Employer
 incorporation or organization)    Classification Code Number)    Identification No.)
1389 MOFFET PARK DRIVE
                           SUNNYVALE, CALIFORNIA 94089
               (Address of principal executive offices) (Zip Code)

                             REDBACK NETWORKS, INC.
                            1999 STOCK INCENTIVE PLAN
                       1999 EMPLOYEE STOCK PURCHASE PLAN
                           1999 DIRECTORS' OPTION PLAN
                 SIARA SYSTEMS, INC. 1998 EQUITY INCENTIVE PLAN

                            (Full title of the Plans)

                                DENNIS L. BARSEMA
                            CHIEF EXECUTIVE OFFICER
                             REDBACK NETWORKS, INC.
                             1389 MOFFET PARK DRIVE
                           SUNNYVALE, CALIFORNIA 94089
                     (Name and address of agent for service)

                                 (408) 548-3500
          (Telephone number, including area code, of agent for service)
2
CALCULATION OF REGISTRATION FEE
==================================================================================================================
                                                             PROPOSED MAXIMUM    PROPOSED MAXIMUM       AMOUNT OF
                                          AMOUNT TO BE      OFFERING PRICE        AGGREGATE         REGISTRATION
TITLE OF SECURITIES TO BE REGISTERED      REGISTERED(1)       PER SHARE         OFFERING PRICE           FEE
------------------------------------      -------------    ----------------    ----------------     ------------
1999 STOCK INCENTIVE PLAN

Options to Purchase Common Stock          5,194,846            N/A              N/A                  N/A

Common Stock, $0.0001 par value           5,194,846 shares     $357.50(3)       $1,857,157,445(3)    $490,289.57

1999 EMPLOYEE STOCK PURCHASE PLAN

Rights to purchase Common Stock           1,000,000            N/A              N/A                  N/A

Common Stock, $0.0001 par value           1,000,000 share      $357.50(3)       $  357,500,000(3)    $ 94,380.00

1999 DIRECTORS' OPTION PLAN

Options to purchase Common Stock          550,000              N/A              N/A                  N/A

Common Stock, $0.0001 par value           550,000 shares       $357.50(3)       $196,625,000(3)      $ 51,909.00

SIARA SYSTEMS, INC. 1998 EQUITY
INCENTIVE PLAN

Options to Purchase Common Stock          2,425,000            N/A              N/A                  N/A

Common Stock, $0.0001 par value           2,425,000 share      $0.86(2)         $  2,085,500(2)      $   550.57
=================================================================================================================
(1)  This Registration Statement shall also cover any additional shares of
     Common Stock which become issuable under the 1999 Stock Incentive Plan, the
     1999 Employee Stock Purchase Plan, the 1999 Directors' Option Plan and the
     Siara Systems, Inc. 1998 Equity Incentive Plan by reason of any stock
     dividend, stock split, recapitalization or other similar transaction
     effected without the receipt of consideration which results in an increase
     in the number of the outstanding shares of Common Stock of Redback
     Networks, Inc.

(2)  Calculated solely for purposes of this offering under Rule 457(h) of the
     Securities Act of 1933, as amended, on the basis of the weighted average
     exercise price of the outstanding options.

(3)  Calculated solely for purposes of this offering under Rule 457(h) of the
     Securities Act of 1933, as amended, on the basis of the average of the high
     and low price per share of Common Stock of Redback Networks, Inc. as
     reported on the Nasdaq National Market on March 9, 2000.
3

PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

     Redback Networks, Inc. (the "Registrant") hereby incorporates by reference
into this Registration Statement the following documents previously filed with
the Securities and Exchange Commission (the "SEC"):

     (a)  The Registrant's Annual Report on Form 10-K for the fiscal year ended
          December 31, 1999;

     (b)  The Registrant's Registration Statement No. 0-25853 on Form 8-A filed
          with the SEC on April 22, 1999, pursuant to Section 12 of the
          Securities Exchange Act of 1934, as amended (the "1934 Act"), in which
          there is described the terms, rights and provisions applicable to the
          Registrant's outstanding Common Stock.

     All reports and definitive proxy or information statements filed pursuant
to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act after the date of this
Registration Statement and prior to the filing of a post-effective amendment
which indicates that all securities offered hereby have been sold or which
deregisters all securities then remaining unsold shall be deemed to be
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filing of such documents. Any statement contained in a
document incorporated or deemed to be incorporated by reference herein shall be
deemed to be modified or superseded for purposes of this Registration Statement
to the extent that a statement contained herein or in any subsequently filed
document which also is deemed to be incorporated by reference herein modifies or
supersedes such statement. Any such statement so modified or superseded shall
not be deemed, except as so modified or superseded, to constitute a part of this
Registration Statement.

Item 4. Description of Securities

     Not Applicable.

Item 5. Interests of Named Experts and Counsel

     Not Applicable.

Item 6. Indemnification of Directors and Officers

     Section 145 of the Delaware General Corporation Law authorizes a court to
award or a corporation's Board of Directors to grant indemnification to
directors and officers in terms sufficiently broad to permit such
indemnification under certain circumstances for liabilities (including
reimbursement for expenses incurred) arising under the Securities Act of 1933,
as amended (the "1933 Act"). The Registrant's Bylaws provide for mandatory
indemnification of its directors and officers and permissible indemnification of
employees and other agents to the maximum extent permitted by the Delaware
General Corporation Law. In addition, the Registrant has entered into
Indemnification Agreements with each of its directors and officers.

Item 7. Exemption from Registration Claimed

     Not Applicable.

Item 8. Exhibits
Exhibit Number      Exhibit
--------------      -------
4              Instrument Defining Rights of Stockholders. Reference is made
                    to Registrant's Registration Statement No. 0-25853 on Form 8-A,
                    which is incorporated herein by reference pursuant to Item 3(p)
                    of this Registration Statement.

     5              Opinion and consent of Gunderson Dettmer Stough Villeneuve
                    Franklin & Hachigian, LLP.

    23.1            Consent of Independent Accountants.

    23.2            Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                    Hachigian, LLP is contained in Exhibit 5.

    24              Power of Attorney. Reference is made to page II-4 of this
                    Registration Statement.
II-1
4

Item 9. Undertakings

     A.   The undersigned Registrant hereby undertakes: (1) to file, during any
period in which offers or sales are being made, a post-effective amendment to
this Registration Statement (i) to include any prospectus required by Section
10(a)(3) of the 1933 Act, (ii) to reflect in the prospectus any facts or events
arising after the effective date of this Registration Statement (or the most
recent post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth in this
Registration Statement and (iii) to include any material information with
respect to the plan of distribution not previously disclosed in this
Registration Statement or any material change to such information in this
Registration Statement; provided, however, that clauses (1)(i) and (1)(ii) shall
not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into this Registration Statement; (2) that for the
purpose of determining any liability under the 1933 Act each such post-effective
amendment shall be deemed to be a new registration statement relating to the
securities offered therein and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof and (3) to remove
from registration by means of a post-effective amendment any of the securities
being registered which remain unsold at the termination of the Registrant's 1999
Stock Incentive Plan, the 1999 Employee Stock Purchase Plan, the 1999 Directors'
Option Plan and the Siara Systems, Inc. 1998 Equity Incentive Plan.

     B.   The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the 1933 Act, each filing of the Registrant's
annual report pursuant to Section 13(a) or Section 15(d) of the 1934 Act that is
incorporated by reference into this Registration Statement shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

     C.   Insofar as indemnification for liabilities arising under the 1933 Act
may be permitted to directors, officers or controlling persons of the Registrant
pursuant to the indemnification provisions summarized in Item 6 or otherwise,
the Registrant has been advised that, in the opinion of the SEC, such
indemnification is against public policy as expressed in the 1933 Act, and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred
or paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the 1933 Act and will be governed by the final
adjudication of such issue.

                                      II-2
5

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8, and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Sunnyvale, State of California on this 15th
day of March, 2000.

                                        REDBACK NETWORKS, INC.

                                        By: /s/ Dennis L. Barsema
                                           -------------------------------------
                                           Dennis L. Barsema
                                           Chief Executive Officer

                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

     That the undersigned officers and directors of Redback Networks, Inc., a
Delaware corporation, do hereby constitute and appoint Dennis L. Barsema and
Craig M. Gentner, and either of them, the lawful attorneys-in-fact and agents
with full power and authority to do any and all acts and things and to execute
any and all instruments which said attorneys and agents, and either one of them,
determine may be necessary or advisable or required to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules or
regulations or requirements of the Securities and Exchange Commission in
connection with this Registration Statement. Without limiting the generality of
the foregoing power and authority, the powers granted include the power and
authority to sign the names of the undersigned officers and directors in the
capacities indicated below to this Registration Statement, to any and all
amendments, both pre-effective and post-effective, and supplements to this
Registration Statement, and to any and all instruments or documents filed as
part of or in conjunction with this Registration Statement or amendments or
supplements thereof, and either of the undersigned hereby ratifies and confirms
all that said attorneys and agents, or either one of them, shall do or cause to
be done by virtue hereof. This Power of Attorney may be signed in several
counterparts.

     IN WITNESS WHEREOF, each of the undersigned has executed this Power of
Attorney as of the date indicated.

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed below by the following persons in
the capacities and on the dates indicated.
Signature                            Title                           Date
            ---------                            -----                           ----
/s/ Dennis L. Barsema              Chief Executive Officer                   March 15, 2000
--------------------------------   and Director (Principal Executive
Dennis L. Barsema                  Officer)

/s/ Craig M. Gentner               Senior Vice President of Finance,         March 15, 2000
--------------------------------   Chief Financial Officer and
Craig M. Gentner                   Corporate Secretary

/s/ James R. Flach                 Director                                  March 14, 2000
--------------------------------
James R. Flach

                                   Director
--------------------------------
Promod Haque

                                   Director
--------------------------------
Vinod Khosla

/s/ William Kurtz                  Director                                  March 14, 2000
--------------------------------
William Kurtz

/s/ Pierre R. Lamond               Director                                  March 14, 2000
--------------------------------
Pierre R. Lamond

/s/ Vivek Ragavan                  President, Chief Operating                March 14, 2000
--------------------------------   Officer and Director
Vivek Ragavan

/s/ Daniel J. Warmenhoven          Director                                  March 14, 2000
--------------------------------
Daniel J. Warmenhoven
II-3
6

                       SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.

                                    EXHIBITS

                                       TO

                                    FORM S-8

                                      UNDER

                             SECURITIES ACT OF 1933

                             REDBACK NETWORKS, INC.
7

                                  EXHIBIT INDEX
Exhibit Number      Exhibit
--------------      -------
4              Instrument Defining Rights of Stockholders. Reference is made
                    to Registrant's Registration Statement No. 0-25853 on Form 8-A,
                    which is incorporated herein by reference pursuant to Item 3(p)
                    of this Registration Statement.

     5              Opinion and consent of Gunderson Dettmer Stough Villeneuve
                    Franklin & Hachigian, LLP.

    23.1            Consent of Independent Accountants.

    23.2            Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                    Hachigian, LLP is contained in Exhibit 5.

    24              Power of Attorney. Reference is made to page II-4 of this
                    Registration Statement.