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Exhibit 12.1
REDBACK NETWORKS INC.
Computation of Ratio of Earnings to Fixed Charges
Pursuant to Item 503
Regulation S-K
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<CAPTION>
PERIOD FROM
AUGUST 30,
1996
(INCEPTION) THREE MONTHS ENDED
THROUGH YEAR ENDED DECEMBER 31, MARCH 31,
DECEMBER 31, ----------------------------- -------------------
1996 1997 1998 1999 1999 2000
------------- -------- -------- -------- -------- ---------
(DOLLARS IN THOUSANDS)
<S> <C> <C> <C> <C> <C> <C>
Net loss ........................... $(142) $(4,411) $(9,876) $(7,919) $(3,801) $(85,237)
Interest ........................... -- 60 223 319 22 279
Amortization of interest expense
related to warrants issued ...... -- 25 28 28 7 7
Lease rental expense representative
of interest (1) ................. -- 48 147 414 28 196
------ ------ ------ ----- ----- ------
Net loss before fixed charges ...... (142) (4,278) (9,478) (7,158) 3,744) (84,755)
------ ------ ------ ----- ----- ------
Less: fixed charges
Interest ........................... -- 60 223 319 22 279
Amortization of interest expense
related to warrants issued ...... -- 25 28 28 7 7
Lease rental expense representative
of interest (1) ................. -- 48 147 414 28 196
---- ----- ----- ----- ----- ------
Total fixed charges ................ -- 133 398 761 57 482
------ ----- ----- ----- ----- --------
Net loss ........................... $ (142) $(4,411) $(9,876) $(7,919) $(3,801) $(85,237)
====== ====== ====== ====== ====== ========
Ratio of earnings to fixed charges . N/A N/A N/A N/A N/A N/A
Deficiency in earnings ............. $ (2) $(4,411) $(9,876) $(7,919) $(3,801) $(85,237)
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(1) Calculated as one-third of rentals, which is a reasonable
approximation of the interest factor.
(2) Redback had no fixed charges in the period from inception (August 30,
1996) through December 31, 1996.
