Second Amendment to Lease Agreement between Corporate Technology Centre Associates LLC and Redback Networks Inc.

Exhibit 10.12

Building 4

SECOND AMENDMENT TO LEASE

                 This SECOND AMENDMENT TO LEASE (this "Amendment") is dated as of this 13th day of October, 2000, by and between CORPORATE TECHNOLOGY CENTRE ASSOCIATES LLC, a California limited liability company ("Landlord"), and REDBACK NETWORKS INC ., a Delaware corporation ("Tenant").

RECITALS

                 A.      Landlord and Tenant entered into a Lease October 27, 1999 as amended by that certain First Amendment to Lease dated November ___, 1999 (the "Lease"), for premises (the "Premises") with a street address of 350 Holger Way, San Jose, California, and more particularly described in the Lease;

                 B.      Landlord and Tenant now desire to amend the Lease on the terms and conditions set forth herein. Capitalized terms used in this Amendment and not otherwise defined shall have the meanings assigned to them in the Lease.

AGREEMENT

                 NOW THEREFORE , for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, Landlord and Tenant hereby agree as follows:

                 1.       Security Deposit. The amount of the Security Deposit set forth in Article 1 of the Lease is hereby changed to $1,682,754.00.

                 2.       Base Monthly Rent. Commencing on January 1, 2001, the Base Monthly Rent set forth in Article 1 shall be changed as follows:

                 The term "Base Monthly Rent" shall mean the following:

                 3.       Ratification. The Lease, as amended by this Amendment, is hereby ratified by Landlord and Tenant and Landlord and Tenant hereby agree that the Lease, as so amended, shall continue in full force and effect.

                 4.       Miscellaneous.

                            (a)       Voluntary Agreement. The parties have read this Amendment and on the advice of counsel they have freely and voluntarily entered into this Amendment.

                            (b)       Attorney's Fees. If either party commences an action against the other party arising out of or in connection with this Amendment, the prevailing party shall be entitled to recover from the losing party reasonable attorney's fees and costs of suit.

                            (c)       Successors. This Amendment shall be binding on and inure to the benefit of the parties and their successors.

                            (d)       Counterparts. This Amendment may be signed in two or more counterparts. When at least one such counterpart has been signed by each party, this Amendment shall be deemed to have been fully executed, each counterpart shall be deemed to be an original, and all counterparts shall be deemed to be one and the same agreement.

                IN WITNESS WHEREOF , Landlord and Tenant have executed this Amendment as of the date first written above.