<PAGE>
FILED PURSUANT TO RULE 424(B) (3)
FILE NUMBER 333-39692
PROSPECTUS SUPPLEMENT
(To Prospectus dated July 26, 2000)
$500,000,000
[REDBACK NETWORKS LOGO]
5% CONVERTIBLE SUBORDINATED NOTES DUE APRIL 1, 2007
(AND SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF THE NOTES)
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This Prospectus Supplement supplements the Prospectus dated July 26,
2000 relating to resales by selling holders of our 5% Convertible Subordinated
Notes due April 1, 2007 (the "Notes") and shares of our common stock into which
the Notes are convertible. This Prospectus Supplement is incorporated by
reference into the Prospectus, and all terms used herein shall have the meaning
assigned to them in the Prospectus. Our common stock is quoted on the Nasdaq
National Market under the symbol "RBAK."
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The information in the table appearing in the prospectus under the
heading "SELLING HOLDERS" is superseded in part and supplemented by the
information appearing in the following table:
<TABLE>
<CAPTION>
SHARES OF
NOTES NUMBER OF COMMON
BENEFICIALLY SHARES OF STOCK
NOTES OWNED COMMON NUMBER OF BENEFICIALLY
BENEFICIALLY AFTER STOCK SHARES OF OWNED AFTER
OWNED NOTES OFFERING(1) BENEFICIALLY COMMON OFFERING(3)(2)
PRIOR TO OFFERED (IN $1,000) OWNED STOCK (IN $1,000)
OFFERING HEREBY ----------- PRIOR TO OFFERED -----------
NAME OF SELLING HOLDERS (IN $1,000) (IN $1,000) # % OFFERING(2) HEREBY # %
------------------------- ----------- ---------- ---- ---- ----------- ----------- ----- -----
<S> <C> <C> <C> <C> <C> <C> <C> <C>
ABN AMRO Incorporated... 1,000 1,000 0 0 5,243 5,243 0 0
Allstate Insurance
Company.............. 2,500 2,500 0 0 13,107 13,107 0 0
Argent Classic
Convertible
Arbitrage Fund
(Bermuda) Ltd........ 5,000 5,000 0 0 26,215 26,215 0 0
Baptist Health of South
Florida.............. 149 149 0 0 781 781 0 0
Deutsche Bank
Securities, Inc...... 77,613 77,613 0 0 406,924 406,924 0 0
ECT Investments Inc..... 4,000 4,000 0 0 20,972 20,972 0 0
Goldman Sachs and
Company.............. 8,339 8,339 0 0 43,721 43,721 0 0
KBC Financial Products.. 6,000 6,000 0 0 31,458 31,458 0 0
Lydian Overseas
Partners Master Fund
Ltd.................. 2,500 2,500 0 0 13,107 13,107 0 0
Nicholas Applegate
Global Holdings L.P.. 50 50 0 0 262 262 0 0
Oppenheimer Convertible
Securities Fund......... 6,000 6,000 0 0 31,458 31,458 0 0
Pilgrim Convertible Fund 3,829 3,829 0 0 20,075 20,075 0 0
San Diego County
Convertible.......... 1,955 1,955 0 0 10,250 10,250 0 0
</TABLE>
<PAGE>
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(1) It is unknown if, when or in what amounts a selling securityholder may
offer securities for sale and we do not know that the selling
securityholders will sell any or all of the securities offered hereby.
Because the selling securityholders may offer all or some of the
securities pursuant to this prospectus, and because there are currently
no other agreements, arrangements or understandings with respect to the
sale of any of the securities that will be held by the selling
securityholders, no estimate can be given as to the amount of the
securities that will be held by the selling securityholders after
completion of the offering made by this prospectus. However, for purposes
of this table, we have assumed that, after completion of the offering, no
securities will be held by the selling securityholders.
(2) The number of securities beneficially owned is determined under the rules
of the SEC and the information is not necessarily indicative of
beneficial ownership for any other purpose. Under those rules, beneficial
ownership includes any securities as to which the individual has sole or
shared voting power or investment power and also any securities which the
individual has the right to acquire within 60 days after August 30, 2000
through the exercise of any stock option or other right. The inclusion in
the table of securities, however, does not constitute an admission that
the selling securityholders are direct or indirect beneficial owners of
those securities. The selling securityholders have sole voting power and
investment power with respect to all securities of capital stock listed
as owned by the selling securityholders.
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SEE "RISK FACTORS" BEGINNING ON PAGE 8 OF THE ACCOMPANYING PROSPECTUS
TO READ ABOUT FACTORS YOU SHOULD CONSIDER BEFORE INVESTING IN THE NOTES OR
SHARES OF THE COMMON STOCK OFFERED HEREBY.
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THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE
SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS
THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED
UPON THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.
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The date of this Prospectus Supplement is August 31, 2000.
