SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* FRIEZO DAVID C (Last) (First) (Middle) 495 POST ROAD EAST (Street) WESTPORT CT 06880 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol REDBACK NETWORKS INC [ RBAKD ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 04/20/2004
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock(1)	04/20/2004		P		100,000	A	$6.0507	316,417	I(2)	By Lydian Global Opportunities Master Fund Ltd.
Common Stock								20.438	D(3)
Common Stock								2,729,174	I(4)	By Lydian Overseas Partners Master Fund Ltd.
Common Stock								50,802	I(5)	By Dylan (IMA) Ltd.

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* FRIEZO DAVID C (Last) (First) (Middle) 495 POST ROAD EAST (Street) WESTPORT CT 06880 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* LYDIAN ASSET MANAGEMENT L P (Last) (First) (Middle) 495 POST ROAD EAST (Street) WESTPORT CT 06880 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Lydian Overseas Partners Master Fund Ltd (Last) (First) (Middle) LYDIAN OVERSEAS PART. MAST. FUND LTD. THIRD FL. BISHOP'S SQ., REDMOND'S HILL (Street) DUBLIN 2 L2 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Lydian Global Opportunities Master Fund Ltd (Last) (First) (Middle) LYDIAN GLO. OPPORT. MAST. FUND LTD. THIRD FL. BISHOP'S SQ., REDMOND'S HILL (Street) DUBLIN 2 L2 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. This Form 4 is being filed by David C. Friezo, Lydian Asset Management L.P. ("Advisor"), Lydian Overseas Partners Master Fund Ltd. ("Overseas") and Lydian Global Opportunities Master Fund Ltd. ("Global") (collectively, Mr. Friezo, Advisor, Overseas and Global are referred to herein as the "Reporting Persons"). The Reporting Persons may be deemed to constitute a "group" for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act" ). Mr. Friezo is the managing member and controlling holder of the general partner of the Advisor, which is the investment advisor to Overseas and Global, and is a director of the Issuer.

2. These securities are held by Lydian Global Opportunities Master Fund Ltd. In accordance with Instruction 4(b)(iv) of Form 4, each of Advisor and Mr. Friezo is reporting the entire amount of such holding but disclaims beneficial ownership over such securities for purposes of Section 16 of the Exchange Act, except to the extent of its or his indirect pecuniary interest therein. No Reporting Person other than those referred to in this footnote has any pecuniary interest in the shares held by Global.

3. These securities are held directly by Mr. Friezo. No other Reporting Person has any pecuniary interest in the securities held by Mr. Friezo.

4. These securities are held by Lydian Overseas Partners Master Fund Ltd. In accordance with Instruction 4(b)(iv) of Form 4, each of Advisor and Mr. Friezo is reporting the entire amount of such holding but disclaims beneficial ownership over such securities for purposes of Section 16 of the Exchange Act, except to the extent of its or his indirect pecuniary interest therein. No Reporting Person other than those referred to in this footnote has any pecuniary interest in the shares held by Overseas.

5. These securities are held by Dylan (IMA) Ltd. ("Dylan"). In accordance with Instruction 4(b)(iv) of Form 4, each of Advisor and Mr. Friezo is reporting the entire amount of such holding but disclaims beneficial ownership over such securities for purposes of Section 16 of the Exchange Act, except to the extent of its or his indirect pecuniary interest therein. No Reporting Person other than those referred to in this footnote has any pecuniary interest in the shares held by Dylan.

	/s/ David C. Friezo	05/03/2004
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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