Infonetics Research Affirms Sonus Networks as Packet Voice Leader for Third Quarter

For more information, please contact:

Infonetics Report Shows Sonus Holds More Than Half of Convergence Switch Market Share

WESTFORD, Mass., November 25, 2003 – Sonus Networks (Nasdaq: SONS) today announced that Infonetics Research has named Sonus the leading provider of carrier packet voice switches. Last week, Infonetics issued its Next Gen Voice Products Worldwide Market Share and Forecast for 3Q03, which examines the markets for a variety of carrier voice equipment including media gateways, softswitches, session border controllers, media servers and voice application servers.

In the latest Infonetics report, Sonus was ranked:

• #1 in Convergence Switch revenues, worldwide
• #1 in Convergence Switch revenues, North America 
• #1 in Convergence Switch port shipments, North America
• #1 in Convergence Switch revenues, EMEA
• #1 in Convergence Switch port shipments, EMEA

"Sonus turned in an extremely strong performance for the third quarter, garnering more than half of the revenues in the global Convergence Switch category, and Sonus' leadership is particularly pronounced in North America, where it holds more than 90% market share," commented Kevin Mitchell, directing analyst, Service Provider Networks and Next Gen Voice at Infonetics Research. "As the top provider of convergence switches, Sonus is leading the way in helping carriers as they migrate from legacy circuit-switched infrastructure to next-gen packet voice."

"The findings by Infonetics reflect the addition of several new customers over the past quarter and the expansion of our existing customers" networks, which now carry nearly 6 billion minutes of traffic per month, " said Michael O'Hara, vice president, marketing, Sonus Networks. "Moreover, we continue to see a shift in our customer base as incumbent service providers select Sonus' industry-leading solutions as the foundation for their next-generation packet voice networks."

In addition to the report published by Infonetics, Sonus has also been recognized by Synergy Research Group and In-Stat/MDR as the leader in several key segments of the carrier-class packet voice equipment market for the third quarter.

About Sonus Networks

Sonus Networks, Inc., is a leading provider of packet voice infrastructure solutions for wireline and wireless service providers. With its Open Services Architecture (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 the "Cautionary Statements" section of Sonus' Quarterly Report on Form 10-Q, dated November 10, 2003 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. In addition, 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. Open Services Architecture is a trademark of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.