Sonus Adds Support for National Security and Emergency Preparedness Communications to Industry Leading IP-Based Voice Solutions

CHELMSFORD, Mass., November 30, 2006 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today a suite of IP-based voice calling solutions to serve National Security/Emergency Preparedness (NS/EP) needs as outlined by the National Communications System (NCS), whose Executive Agent is the Department of Homeland Security. The mission of the NCS is to assist the President, government agencies, and critical industry through the delivery of NS/EP communications, which require a high probability of completion during periods of network congestion, including crisis or emergency, attack, recovery and reconstitution.

"In the past five years especially, we've seen how critical it is to be able to communicate effectively in crisis situations," said John Graves, Government Emergency Telecommunications Service and Wireless Priority Service Program Director, NCS. “Sonus is a recognized leader in the IP voice world and their new NS/EP feature offering will help ensure that IP networks meet the emergency communications requirements for high probability of completion."

Working in collaboration with the NCS and its integration contractor, Computer Sciences Corporation (CSC), Sonus Networks has developed a robust set of next generation network features that meet the requirements outlined by the NCS. Most recently, the NCS enlisted the support of Sonus to develop two new features to round out its NS/EP services product functionality: Session Initiation Protocol (SIP) Resource Priority Header (RPH) and Office Wide Call Queuing (OWCQ), which together identify and allocate resource priority to calls from authorized federal, state, local, and critical industry personnel who have NS/EP missions. Sonus Networks is the first to develop this set of next generation NS/EP features and recently hosted a demonstration in their Richardson, Texas, laboratories for NCS, CSC, other NCS contractors, and a group of leading U.S. carriers. The Richardson lab is Sonus' largest customer integration and testing facility.

“Sonus has been a critical ally in efforts to define IP standards for NS/EP priority needs", noted Dennis Berg, Engineering Director, CSC. “Now Sonus is the first-to-market with products that realize NCS service requirements based upon these standards".

“There's been a lot of attention around enhanced 911, but just as important is the ability for NS/EP responders to be able to place calls with important information and instructions in times of crises," said Vikram Saksena, chief scientist, Sonus Networks. “We are committed to helping our customers build networks that function reliably in even the most strenuous circumstances, when the ability to communicate is most important."

To ensure that NS/EP communications are being addressed across various network types, the NCS has implemented the Government Emergency Telecommunications Service (GETS) and Wireless Priority Service (WPS). Sonus' NS/EP product portfolio is designed to meet the needs of each of these two services.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice over IP (VoIP) infrastructure solutions for wireline and wireless service providers. With its comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services. Sonus' voice infrastructure solutions are deployed in service provider networks worldwide. Founded in 1997, Sonus is headquartered in Chelmsford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain forward-looking statements regarding future events that involve risks and uncertainties. Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results. Readers are referred to the “Risk Factors" section of Sonus' Quarterly Report on Form 10-Q, dated May 8, 2006, filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include among others: the impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks and uncertainties associated with the Company's announced review of its historical stock option grants and accounting, including any potential impact of the Company's financial statements or results, the Company's inability to timely report with the Securities and Exchange Commission, the Company's potential inability to meet NASDAQ requirements for continued listing, potential investigations or litigation arising out of the review or any restatement; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities litigation against the company. Any forward-looking statements represent Sonus' views only as of today and should not be relied upon as representing Sonus' views as of any subsequent date. While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so.

Sonus is a registered trademark of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.