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Report Issued by Synergy Research Group Confirms Sonus' Leadership Position

WESTFORD, Mass., December 4, 2000 – Sonus Networks (Nasdaq: SONS) today announced that it has been named the worldwide leader in providing carrier-class voice-over-packet media gateways and softswitch solutions to the telecommunications industry. The company's top position is reflected in a recent report issued by Synergy Research Group. According to the report, which examines survey data for the first nine months of 2000, Sonus has been ranked number one in both the carrier-class voice-over-packet media gateway and softswitch categories.  

Synergy has estimated that the worldwide market for voice over packet and Internet offload - just two of the applications for the new public network - will grow to approximately $19 billion by 2003. Voice infrastructure solutions, such as the carrier-class media gateways and softswitches provided by Sonus, are key network building blocks supporting these applications.  

"As a company, we are singularly focused on becoming the premier franchise for next-generation voice infrastructure solutions," said Gary Rogers, vice president, worldwide sales and marketing, Sonus Networks. "It is extremely gratifying to be recognized as a market leader by a respected organization such as Synergy Research, and more importantly, by our carrier customers." 

Rapidly growing customer acceptance of Sonus' Packet Telephony suite, including the award-winning GSX9000 Open Services Switch and the PSX6000 SoftSwitch, has propelled Sonus to the leading position in the market for next-generation voice solutions. The GSX9000 and PSX6000 form the cornerstone of a system that delivers the scalability, reliability, interconnectivity and voice quality required for deployment in global service provider networks. Moreover, the Sonus solution offers a powerful and open platform upon which carriers can build new revenue streams through the rapid development and delivery of innovative voice and data services.    

"Sonus has quickly emerged as a driving force in the carrier market for packet-based equipment. With its strong suite of technology and its experienced management team, coupled with a growing list of strategic customer relationships, Sonus is gearing up to re-write how carriers will provision services to businesses and residences," said Jeremy Duke, founder and principal analyst, Synergy Research Group.

"The momentum for voice over packet in 2000 was driven by Class 4 tandem applications, and we believe in 2001 we will see an even greater momentum for purpose-built, carrier-class gateways that will provide such services, as well as Class 5 access solutions," continued Duke. "The introduction of Class 5 packet technology will provide emerging and existing carriers an ability to expand their service geographies in unprecedented time-to-market as well as provide an augmentation and migration strategy for the installed base of central office switches."

Constructed from a strict methodology, the Synergy Research Group report is based on original surveys of top equipment manufacturers in the networking and telecommunications industries, and compares more than 80 companies.  For information on obtaining this report, please contact Kelly Grommes, Synergy Research's director of sales and marketing at 1-602-287-9097, ext. 1.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice infrastructure products for the new public network. Sonus' solutions enable service providers to deploy an integrated network capable of carrying both voice and data traffic, and to deliver a range of innovative, new services. The Sonus Open Services ArchitectureTM (OSA) and award-winning Packet Telephony suite cut the time-to-market for competitive new service products, allowing carriers and third-party developers to expand market share and build important new revenue streams. Its highly scalable products fully interoperate with and extend the life and utility of today's public network. Sonus embodies in its management and staff decades of experience in developing carrier-class voice, data and multimedia solutions for implementation in the world's largest networks. 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 for the quarter ended September 30, 2000, 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 Company's 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.

GSX9000, PSX6000 and Open Services Architecture are trademarks of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.