July 9, 2008

Sycamore Networks SN 9000 Intelligent Multiservice Switch Completes DISA Joint Interoperability Assessment Testing

Sycamore Networks, Inc. (NASDAQ: SCMR), a leading provider of intelligent bandwidth management solutions for network operators worldwide, today announced that its SN 9000 Intelligent Multiservice Switch has successfully completed rigorous interoperability testing with the US Defense Information Systems Agency (DISA) Joint Interoperability Test Command (JITC). JITC assessment and approval is required for systems intended to participate in US Department of Defense networks.

The SN 9000 joins other Sycamore optical switching solutions - including the previously certified SN 16000, SN 3000, and SILVX(R) Network Management System - in successfully completing JITC interoperability testing. By reaching this milestone with the SN 9000, Sycamore has strengthened its position as an established provider of JITC-approved, core-to-edge optical switching solutions.

During the JITC evaluation, Sycamore's SN 9000 successfully completed a battery of standards conformance and systems performance tests involving a variety of broadband optical and electrical interfaces, including procedures for traffic capacity and stress response, failure recovery, traffic protection and re-routing, and verification of data and control planes.

"We are very pleased to successfully complete JITC interoperability testing of the SN 9000," said Jim Mooney, vice president of product management and marketing at Sycamore. "This milestone is further evidence of Sycamore's commitment to the demanding and rapidly evolving communications requirements of our military, and our ability to meet those needs with a broad portfolio of intelligent bandwidth management platforms."

Sycamore's SN 9000 brings important new functionality to multiservice switching - including unique bandwidth capacity licensing, service modularity, and any-service, any-port features - in a solution that is "right-sized" for applications in the 80-320 Gbps bandwidth range. It is designed to cost-effectively integrate multiple functions in a single, highly-compact system that can include low-order (VT/VC) and high-order (OC-n/STM-n) switching, add-drop multiplexing, advanced Ethernet services, and integrated optical transport. Extending the proven benefits of Sycamore's GMPLS/ASON-powered intelligent optical networking software and unprecedented configuration flexibility, the SN 9000 is a versatile, carrier-grade platform that sets a higher competitive bar for seamless scalability, operational simplicity, bandwidth granularity, and service resiliency.

Sycamore to Exhibit at LandWarNet 2008 Conference

Sycamore will highlight the SN 9000 platform as part of the AFCEA Technology Showcase during the LandWarNet 2008 conference, August 19-21, at the Broward County Convention Center in Ft. Lauderdale, Florida.

About Joint Interoperability Test Command

The Joint Interoperability Test Command (JITC) conducts testing of national security systems and information technology systems hardware, software and components. Services include developmental, conformance, interoperability, operational and validation testing.

JITC provides "one-stop systems testing" with its one-of-a-kind array of test beds and uniquely qualified staff. The command can interface all of its on-site capabilities and its network with any other testing or operational facility worldwide. The JITC facilities are located at Fort Huachuca, Ariz., and Indian Head, Md. JITC is a member of the Major Range and Test Facility Base (MRTFB).

JITC services the Defense Information Systems Agency (DISA), combatant commands, the Department of Defense (DoD) and other federal agencies, allies, coalition partners and commercial vendors. For complete service descriptions and points of contact, please visit http://jitc.fhu.disa.mil.

About Sycamore Networks

Sycamore Networks, Inc. (NASDAQ: SCMR) is a leading provider of intelligent bandwidth management solutions for fixed line and mobile network operators worldwide. From multiservice access networks to the optical core, Sycamore products enable network operators to lower overall network costs, increase operational efficiencies, and rapidly deploy new revenue-generating services. Sycamore's global customer base includes Tier 1 service providers, government agencies, and utility companies. For more information, please visit www.sycamorenet.com.

We wish to caution you that certain matters discussed in this news release constitute forward-looking statements regarding future events that involve risks and uncertainties. Readers are cautioned that actual results or events could differ materially from those stated or implied in the forward-looking statements. These risks and uncertainties include, but are not limited to, the findings, including possible tax liabilities and penalties resulting from the audit of certain of the Company's income tax returns by the Internal Revenue Service; risks relating to the formal investigation commenced by the Securities and Exchange Commission, such as a civil proceeding which may seek, among other things, injunctive relief and a civil penalty, with respect to certain stock options granted by the Company; the investigation by the U.S. Attorney's office with respect to stock option matters; and other additional actions and findings that may result from the ongoing investigation into such stock options and the accounting therefore, including the restatement of previously issued financial statements and certain purported shareholder derivative actions filed against the Company and certain of its current and former officers and directors; the Company's reliance on a limited number of customers; variation in the company's quarterly results; industry pricing pressures and the high cost of product development required to remain competitive and keep pace with evolving features and technologies desired by customers; the consolidation of both suppliers and customers in the telecommunications marketplace and general economic conditions. Certain additional risks are set forth in more detail in the section entitled "Risk Factors" in the Company's most recent Quarterly Report on Form 10-Q and Annual Report on Form 10-K filed by the Company with the Securities and Exchange Commission. The Company disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future results or otherwise.