SUBLEASE AGREEMENT

Exhibit 10.19

SUBLEASE AGREEMENT

SUBLEASE

This Sublease (“Sublease”) is entered into as of the 29 ^th day of June, 2004, by and between BigBand Networks, Inc., a Delaware corporation (“Sublessee”), and ADC Telecommunications, Inc., a Delaware corporation, as successor-in-interest to ADC Broadband Access Systems, Inc. (“Sublessor”). Pursuant to that certain Lease dated June 13, 1999, entered into by and between Gateway Sherwood, Inc., a California corporation, by RREEF America LLC, a Delaware limited liability company, its investment advisor (“Lessor”), as landlord, Sublessor’s predecessor-in-interest ADC Broadband Access Systems, Inc. (f/k/a Broadband Access Systems, Inc.), as tenant (“Original Lease”), as amended by the First Amendment to Lease dated October 22, 1999 (“First Amendment”), as further amended by the Second Amendment to Lease dated April 18, 2000 (“Second Amendment”), as further amended by the Third Amendment to Lease dated April 1, 2002 (“Third Amendment”), and as Sublessor’s interest was assigned in Assignment of Lease dated May 24, 2004 (“Assignment”) (with the Original Lease, First Amendment, Second Amendment, Third Amendment and Assignment collectively referred to herein as “Lease”), Sublessor leased from Lessor certain premises in the building located at 8 Technology Drive, Westborough, Massachusetts (“Building”), as more particularly described in the Lease (“Original Premises”). A copy of said Lease is attached hereto, marked Exhibit A. Pursuant to this Sublease, Sublessor has agreed to sublease to Sublessee a, portion of the Original Premises, as more particularly described herein, upon the terms and conditions set forth herein.

Sublessor leases to Sublessee, and Sublessee hires from Sublessor, 63,972 rentable square feet on the first and second floor, as shown on the attached floor plan, marked Exhibit B (“Premises”).

(a) This Sublease is subject to all of the terms and conditions of the Lease, and all amendments thereto; provided, however, Sublessee’s consent must obtained for any and all amendments after the date hereof that materially adversely affect any of Sublessee’s rights thereunder. Sublessee shall in no case have any rights under this Sublease that exceed Sublessor’s rights as tenant under the Lease. Sublessee shall neither do nor permit to be done anything which would constitute a default under the Lease or cause the Lease to be terminated or forfeited by reason of any right of termination or forfeiture reserved or vested in Lessor thereunder. Sublessee shall assume and perform the obligations of Sublessor as tenant in the Lease to the extent said terms and conditions are applicable to the Premises, except as expressly set forth herein. In the event of any conflicts between the terms of the Sublease and the terms of the Lease, for all purposes hereof, the terms of the Sublease shall control; however, to the extent that an issue is not addressed in the Sublease, and also not specifically excluded herein, the terms

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of the Lease shall control. Sublessee shall not commit or permit to be committed on the Premises any act or omission which shall violate any term or condition of the Lease incorporated under this Sublease. In the event of the termination of Sublessor’s interest as tenant under the Lease for any reason, other than a voluntary termination agreed to by Lessor and Sublessor, then this Sublease shall terminate simultaneously therewith without any liability of Sublessor to Sublessee.

(b) Except as otherwise set forth herein, all of the terms and conditions contained in the Lease are incorporated herein, as terms and conditions of this Sublease (with each reference therein to Lessor, as landlord, and Sublessor, as tenant, to be deemed to refer to Sublessor, as landlord, and Sublessee, as tenant, respectively), and along with all of the following paragraphs set out in this Sublease shall be the complete terms and conditions of this Sublease. The consent of Sublessor shall be required in connection with any act which requires the consent of Lessor, as landlord, pursuant to the Lease, notwithstanding that a particular provision herein may not require Sublessor’s consent or states that only Lessor’s consent is required.

(c) The terms, provisions, covenants, and conditions of the Lease are incorporated herein by reference on the following mutually accepted understandings:

(i) In any case where the Lessor reserves the right to enter the Original Premises pursuant to the Lease, said right shall inure to the benefit of the Lessor as well as to Sublessor with respect to entry onto the Premises.

(ii) With respect to the performance of any other obligations required of Lessor under the Lease, including, but not limited to, work, services, repairs, repainting and restoration, Sublessor’s sole obligation shall be to act on Sublessee’s behalf in requesting the performance of the same of Lessor, after first receiving a request in writing from Sublessee, and to use its best efforts in order to obtain the performance of the same from Lessor.

(iii) Notwithstanding anything in this Sublease or the Lease to the contrary, Sublessee agrees that Sublessor shall not be obligated to furnish for or to Sublessee any service of any nature whatsoever. However, in accordance with provision (ii) above, Sublessor shall act on Sublessee’s behalf in requesting the performance of such services for the Premises by Lessor pursuant to the terms of the Lease.

(iv) Since Lessor’s consent to this Sublease is required pursuant to the terms of the Lease, this Sublease and the obligations of the parties hereto shall be contingent upon Sublessor obtaining the consent of the Lessor to this Sublease. The parties hereto agree to be bound by the terms of this Sublease until such time as such consent of the Lessor has been obtained, or until such consent is deemed to have been granted pursuant to the terms of the Lease. If for any reason such consent of the Lessor is not obtained, this Sublease shall then be null and void and both parties will be released from their obligations hereunder.

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(v) Notwithstanding anything in this Sublease to the contrary, this Sublease shall not incorporate any provision of the Lease nor shall Sublessee benefit from the rights or privileges contained in any provision of the Lease, which, pursuant to and in accordance with its particular terms and conditions is not applicable to subleases or assignments, or any provision of the Lease, which by its nature or pursuant to a specified prohibition contained in the Lease, is personal to Sublessor or would not convey or transfer by a sublease or assignment of all or a portion of the Original Premises. For the avoidance of doubt, the following sections shall not be incorporated herein: Sections 2, 3, and 5 and Exhibit B and Schedule 1 of the Original Lease; Sections 5(b), (c) and (d), 6 and 7 of the First Amendment; Sections 5(b), (c) and (d), 6,7, 8 and 9 of the Second Amendment; and Sections 4, 5, 6(b), (c) and (d), 7,11, 12 and 14 of the Third Amendment.

(a) Term : The term (“Term”) of this Sublease shall be for a period of three years (i) commencing on May          , 2004 (“Commencement Date”) and (ii) ending March 31, 2007 (“Expiration Date”), unless sooner terminated as provided pursuant to any provision of the Lease or this Sublease. Sublessor and Sublessee acknowledge and agree that it is the intent of the parties hereto, that, in no event shall the Term of this Sublease extend for a period longer than the term of the Lease, as such Lease term may be cancelled, terminated or reduced, pursuant to such Lease, by agreement between Lessor and Sublessor, or otherwise.

(b) Early Access : In the event that Sublessor shall permit Sublessee to access the Premises prior to the Commencement Date for the construction of improvements, such access shall be subject to all of the provisions of this Sublease, excepting only the payment of Base Rent; provided, however, Sublessee shall be responsible for reimbursing Sublessor for all utility costs and all costs for any other services used by Sublessee during such period of early access. Said early access shall not advance the Expiration Date of this Sublease. Further, any and all additions and improvements made by Sublessee during said period of early access shall be at Sublessee’s sole risk.

(a) Sublessee shall pay to Sublessor as “Base Rent” for the Premises the sum of One Million One Hundred Fifty-one Thousand Four Hundred Ninety-six Dollars ($1,151,496,00), payable on the first day of each calendar month, in equal monthly installments of Ninety-five Thousand Nine Hundred Fifty-eight Dollars ($95,958.00). The first full calendar month’s Base Rent installment shall be paid on the Commencement Date. Sublessee shall be responsible for the payment of any separately metered utilities and after hours HVAC services requested by Sublessee (as provided in Section 13 of the Lease and Section 21 of this Sublease) and any other services related to Sublessee’s occupancy that are billed by Lessor above and beyond the amounts included within Direct Expenses (as defined in the Lease). Sublessor shall be responsible for the payment of 100% of Tenant’s Proportionate Share (as defined in the Lease) of any increase of Direct Expenses and/or Taxes paid or incurred during the Term of this

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Sublease over the Direct Expenses and/or Taxes paid or incurred in the Base Year (as defined in the Lease) as set forth in Article 4 of the Lease, and including, by way of illustration and not limitation, real estate taxes, utilities, janitorial services and interior/exterior building repairs and maintenance. Base Rent for any period during the Term hereof, which is for less than one month, shall be a pro rata portion of the monthly installment.

(b) When any provision of this Sublease requires the payment of any sums of money other than the Base Rent defined above, such sums of money shall be deemed “Additional Rent”, and shall be immediately due and payable, unless otherwise provided for in this Sublease. All Base Rent and Additional Rent are referred to herein collectively as “Rent”. All payments or installments of Rent hereunder and all sums whatsoever due under this Sublease, if not paid when due, shall be subject to a late charge equal to the greater of: (a) Fifty Dollars ($50.00), or (b) five percent (5%) of the payment due for each late payment and shall bear interest at the rate of twelve percent (12%) per annum (but not more than the maximum allowable legal rate applicable) until paid. If an attorney is employed to enforce Sublessor’s rights under this Sublease, Sublessee shall pay all fees and expenses of such attorney. Rent shall be payable without notice or demand and without any deduction, offset, or abatement, in lawful money of the United States of America to Sublessor at the following address, or to such other persons or at such other places as Sublessor may from time to time designate in writing:

ADC Telecommunications, Inc.

Attn: ____________________

13625 Technology Drive

Eden Prairie, MN 55344

Sublessee shall not be able to exercise any rights under Sections 11 or 12 of the Third Amendment. Sublessee shall have no option to renew this Sublease or expansion option, right of first refusal, termination option, or other such option under the Lease, if any. Notwithstanding the foregoing, Sublessor agrees to waive any renewal rights under the Lease for the period after the Expiration Date, if Sublessee requests such waiver in writing, to permit Sublessee to negotiate a new lease for the Premises directly with Lessor.

Sublessor shall deliver to Sublessee the Premises in an “As Is, Where Is” condition, excepting same shall be in a broom clean condition, and Sublessee shall be responsible, at its sole cost, for any desired improvements (including, but not limited to, carpeting, partitions, ceiling tiles, wall treatment and/or lighting). Sublessee shall provide Sublessor with copies of the plans for any improvements and obtain Sublessor’s and Lessor’s written approval prior to commencing any improvements. All interior improvements that are located within the Premises as of the date Sublessee occupies the Premises and are owned by Sublessor, which may include furniture, equipment, cabling, telephone systems, computer systems and Premises-specific

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