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Insignus Softswitch Singled Out for Technical Excellence and Vision

WESTFORD, Mass., December 18, 2002 - Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced that its InsignusTM Softswitch has been named by INTERNET TELEPHONY(R) magazine as a Product of the Year for 2002.  

"This award is testament to the expertise and dedication of all of our employees and reflects our unwavering focus on delivering robust, proven packet voice solutions to our carrier customers," said Michael O'Hara, vice president, marketing, Sonus Networks.  "We are honored to be recognized for our product leadership by such a respected publication as INTERNET TELEPHONY."

The Insignus Softswitch, which has been shipping since June 1999, has been deployed by leading carriers such as Deutsche Telekom, Qwest, BellSouth, NTT Communications and Global Crossing, driving nearly 4 billion minutes of traffic each month.  The Insignus Softswitch supports a range of applications including trunking, residential access and Centrex, tandem switching, and IP voice termination, as well as enhanced services.  The Insignus Softswitch also offers extensive international capabilities for next-generation packet voice deployments, and supports nearly 30 different international signaling variants, in addition to international versions of ISDN PRI and CAS.  

"The Product of the Year award recognizes the outstanding teams who developed and manufactured the products and services on our winning list," said INTERNET TELEPHONY editorial director Greg Galitzine.  "Choosing the winners was a difficult process, but Sonus Networks truly deserved the honor of Product of the Year due to its proven commitment to delivering quality products and its pioneering role in the development of the packet voice market."  

About Internet Telephony Magazine

The convergence of voice, video, fax, and data has revolutionized the world of telecommunications. Internet telephony has been proven to drastically reduce long-distance costs and continues to provide unprecedented opportunities for service providers, resellers, developers, and end users alike. Internet Telephony is the only magazine that focuses on providing the information that will help you take advantage of this exciting technology. Launched as a quarterly publication in January 1998, Internet Telephony(R) magazine has been published monthly since October 1998.  Internet Telephony(R) provides readers with the best information necessary to learn about and purchase the equipment, software, and services they need to take advantage of Internet telephony. 

About TMC

Since 1972, Technology Marketing Corporation (TMC(TM)) has produced industry-leading trade magazines and events focused on technology and telecommunications. TMC(R) publishes two magazines: Customer Inter@ction Solutions(TM) and Internet Telephony, and two online publications, Planet PDA(TM) Magazine and BiometriTech(TM) Magazine. TMC is also the first publisher to test new products in its own on-site laboratories, TMC Labs(R), and provide factual and unbiased product reviews.  TMC also produces INTERNET TELEPHONY Conference & Expo, Planet PDA(TM): The Enterprise PDA Event and BiometriTech Conference & Expo.  TMCnet.com publishes more than 25 topical online newsletters. For more information about TMC, visit its Web site at www.tmcnet.com.

About Sonus Networks

Sonus Networks, Inc., is a leading provider of packet voice infrastructure products for the new public network.  With its Open Services ArchitectureTM (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking, residential access and Centrex, tandem switching, and IP voice termination, as well as enhanced services.  Sonus' award-winning voice infrastructure solutions, including media gateways, softswitches and network management systems, are deployed in service provider networks worldwide.  Sonus, founded in 1997, is headquartered in Westford, Massachusetts.  Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain projections or other forward-looking statements regarding future events or the future financial performance of Sonus 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 Sonus' Quarterly Report on Form 10-Q, dated November 13, 2002 and filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements.  These risk factors include, among others, the adverse effect of recent developments in the telecommunications industry, the weakened financial position of many service providers, Sonus' ability to grow its customer base, dependence on new product offerings, market acceptance of its products, rapid technological and market change and manufacturing and sourcing risks.

Insignus and Open Services Architecture are trademarks of Sonus Networks.  All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.