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* CHARLES RIVER PARTNERSHIP XI LP (Last) (First) (Middle) 1000 WINTER STREET SUITE 3300 (Street) WALTHAM MA 02451 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol BigBand Networks, Inc. [ BBND ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 11/23/2009
	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	11/23/2009		S		43,400(1)	D	$3.7074	8,919,770(2)(3)(4)	I	See Footnotes (2)(3)(4)

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* CHARLES RIVER PARTNERSHIP XI LP (Last) (First) (Middle) 1000 WINTER STREET SUITE 3300 (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Charles River Friends XI-A, LP (Last) (First) (Middle) 1000 WINTER STREET SUITE 3300 (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Charles River Friends XI-B, LP (Last) (First) (Middle) 1000 WINTER STREET SUITE 3300 (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Charles River XI GP, LP (Last) (First) (Middle) 1000 WINTER STREET SUITE 3300 (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Charles River XI GP, LLC (Last) (First) (Middle) 1000 WINTER STREET SUITE 3300 (Street) WALTHAM MA 02451 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Represents 42,113 shares sold by Charles River Partnership XI, LP ("CRP XI"), 1,064 shares sold by Charles River Friends XI-A, LP ("CRF XI-A") and 223 shares sold by Charles River Friends XI-B, LP ("CRF XI-B").

2. Represents 8,650,638 shares held by CRP XI, 224,365 shares held by CRF XI-A and 44,767 shares held by CRF XI-B.

3. Charles River XI GP, LLC ("CR XI GP LLC") is the General Partner of Charles River XI GP, LP ("CR XI GP LP"). CR XI GP LLC is also the General Partner of CRF XI-A and CRF XI-B. CR XI GP LP is the General Partner of CRP XI. CRP XI, CRF XI-A and CRF XI-B (collectively, the "Partnerships") form a "group" for purposes of Section 13(d) of the Securities Exchange Act of 1934. Each of Izhar Armony, Christopher Baldwin, Richard M. Burnes, Jr., Ted R. Dintersmith, Bruce I. Sachs, William P. Tai, and Michael J. Zak is a managing member of CR XI GP, LLC.

4. Accordingly, each of CR XI GP LP, CR XI GP LLC and Messrs. Armony, Baldwin, Burnes, Dintersmith, Sachs, Tai, and Zak (collectively, the "Management Persons") may be deemed to beneficially own the securities owned by the Partnerships. Each of the Management Persons disclaims beneficial ownership of the securities reported herein held by the Partnerships, except to the extent of such person's pecuniary interest in each applicable Partnership, if any. The filing of this statement by any reporting person shall not be deemed an admission that such person is, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the beneficial owner of any equity securities covered by this statement.

Remarks:

Each of Izhar Armony, Christopher Baldwin, Richard M. Burnes, Jr., Ted R. Dintersmith, Bruce I. Sachs, William P. Tai, and Michael J. Zak (the "Individual Management Persons") is also a reporting person. Because the SEC's filing system will not accept CIK and CCC codes from more than ten joint filers of a report, the individual Management Persons have filed separately from this Form 4. Such other Form 4 and this Form 4 relate to the same securities and transactions. Thus, in total, there are twelve (12) joint filers: Charles River Partnership XI, LP, Charles River Friends XI-A, LP, Charles River Friends XI-B, LP, Charles River XI GP, LP, Charles River XI GP, LLC, Izhar Armony, Christopher Baldwin, Richard M. Burnes, Jr., Ted R. Dintersmith, Bruce I. Sachs, William P. Tai, and Michael J. Zak.

	/s/ John A. Genest, Attorney-in-Fact for Charles River XI GP, LLC, general partner of Charles River XI GP, LP, general partner of Charles River Partnership XI, LP	11/25/2009
	/s/ John A. Genest, Attorney-in-Fact for Charles River XI GP, LLC, general partner of Charles River Friends XI-A, LP	11/25/2009
	/s/ John A. Genest, Attorney-in-Fact for Charles River XI GP, LLC, general partner of Charles River Friends XI-B, LP	11/25/2009
	/s/ John A. Genest, Attorney-in-Fact for Charles River XI GP, LLC, general partner of Charles River XI GP, LP	11/25/2009
	/s/ John A. Genest, Attorney-in-Fact for Charles River XI GP, LLC	11/25/2009
	** Signature of Reporting Person	Date
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* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
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