Industry Research Firms Issue Reports Showing Sonus as Number One Provider in Several Areas  

WESTFORD, Mass., August 26, 2003  – Sonus Networks (Nasdaq: SONS) today announced that it has been named a leading player in the service provider packet voice market by industry research firms Synergy Research Group and iLocus. Recently released data from Synergy and iLocus show Sonus as market share leader in key categories such as carrier VoIP gateway revenues, minutes of VoIP traffic and revenue-generating carrier ports.

Synergy Research Group recognized Sonus as a top performer in its second quarter 2003 analysis of the voice over IP (VoIP) equipment market.Synergy last week issued its market share report for Q2, revealing that Sonus owned the largest market share of high-density VoIP gateway revenues worldwide, with 50.9% share.

“Sonus had an impressive second quarter, increasing its leadership position in providing high-density carrier class VoIP gateways to the industry,” said Jeremy Duke, founder and principal analyst, SynergyResearch Group. “Sonus garnered more than half of the revenues in that category, and also expanded its share in several other areas.”

Sonus has been deploying its packet voice infrastructure solutions including the GSX9000 Open Services Switch, the Insignus Softswitch and the Sonus Insight Management System since 1999, and networks based on Sonus solutions now carry more than 5 billion minutes per month. With signaling variant support for more than 30 countries, Sonus's systems have been implemented by incumbent service providers and next-generation carriers around the globe.

Market analysis firm iLocus recently issued their fourth annual VoIP industry update report, which provides a quantitative view of the global VoIP market and also identifies trends for the coming year. In that report, iLocus named Sonus the market share leader in ports carrying commercial long distance VoIP traffic, as well as the leader in minutes of domestic long distance VoIP traffic.

"Carriers are driving forward in the migration to packet voice networks, and are running increasingly large amounts of voice traffic on a packet-based infrastructure," said Michael O'Hara, vice president, Sonus Networks. "As a pioneer in the packet voice market, Sonus is leading the way in helping service providers make the transition from legacy circuit networks to next-generation voice networks. We are very proud that a high percentage of packet voice traffic is delivered over Sonus Networks solutions, and are pleased that we continue to be recognized as a leader by these industry research firms."

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 August 13, 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, GSX9000, Insignus and Sonus Insight are trademarks of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.