Sycamore Subject to Nasdaq Delisting

CHELMSFORD, Mass. -- Sycamore Networks, Inc. (NASDAQ: SCMR - News) today announced that due to the delay in filing its Form 10-Q for the period ended April 30, 2005, it has received a letter from the Staff of The Nasdaq Stock Market indicating that the Company's common stock is subject to delisting pursuant to Nasdaq Marketplace Rule 4310(c)(14). Nasdaq Marketplace Rule 4310(c)(14) requires the Company to make on a timely basis all filings with the Securities and Exchange Commission, as required by the Securities Exchange Act of 1934, as amended.

Sycamore will appeal the Nasdaq Staff's determination by requesting a hearing before a Nasdaq Listing Qualifications Panel, which will automatically stay the delisting of SCMR common stock pending the Panel's review and determination. Until the Panel issues a determination and the expiration of any exception granted by the Panel, Sycamore's common stock will continue to be traded on The Nasdaq National Market. However, as a result of the delayed filing of its Form 10-Q, the trading symbol for the Company's common stock will be changed from SCMR to SCMRE effective as of the opening of business on June 20, 2005.

As previously announced, Sycamore has delayed filing its Quarterly Report on Form 10-Q due to an internal investigation being directed by its Audit Committee relating to the accounting treatment for certain stock options granted during the period from 1999 to 2001, including whether additional stock compensation expenses should have been recorded during the period under review. The Company previously announced this investigation in a press release dated June 7, 2005.

While the Company is working diligently to finalize the internal investigation and complete its Form 10-Q, there can be no assurance that the Panel will grant the Company's request for an exception that would allow the continued listing of the Company's common stock on The Nasdaq Stock Market until the Company files its Form 10-Q for the quarter ended April 30, 2005 with the Securities and Exchange Commission.

Sycamore Networks Inc.