EXHIBIT 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of our reportdated September 26, 2008 relating to the financial statements and the effectiveness of internal control over financial reporting, which appears in Sycamore Networks, Inc.'s Annual Report on Form 10-K for the year ended July 31, 2008.

/s/  PricewaterhouseCoopers LLP

Boston, Massachusetts

January 6, 2009