Sonus Networks Named Leading Provider of Carrier Packet Voice Equipment for Tenth Consecutive Quarter

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Leadership Increases in Q4 Market Share Reports from Key Telecom Industry Research Firms

 WESTFORD, Mass., February 26, 2003 – Sonus Networks (Nasdaq: SONS) today announced that it has been ranked the number one provider of carrier-class packet voice equipment for the fourth quarter of 2002. Industry research firms In-Stat/MDR, Infonetics Research and Synergy Research Group have again named Sonus the market share leader, recently issuing reports recognizing Sonus as the top equipment vendor in several major service provider packet telephony market segments.

"We are extremely pleased to have increased our market share in Q4 and to be named the clear leader in packet telephony for ten straight quarters," said Michael O'Hara, vice president of marketing, Sonus Networks. "Today, service providers across the globe are running 4 billion minutes of traffic over Sonus-based infrastructures each month. We will continue to turn up new customer networks and work with our existing customers to expand their minutes of use. This is the true indicator of leadership."

In its fourth quarter market share analysis, In-Stat/MDR named Sonus the leading provider of purpose-built carrier voice over IP (VoIP) gateway port shipments and revenues, as well as the leader in high-density VoIP gateway port shipments and revenues.

"Sonus remained the market share leader in the fourth quarter in the packet telephony segments in which it competes," said Norm Bogen, director, WAN Infrastructure and Services at In-Stat/MDR. "In fact, Sonus gained significant market share in those segments during the fourth quarter."

Last week, Infonetics Research issued their Next Gen Voice Products report, which found that Sonus gained market share during the fourth quarter. According to Infonetics, Sonus holds the number one position in the Convergence Switch category, with 48 percent market share for overall revenue.

"Sonus' improved performance in the fourth quarter enabled them to increase their market share and solidify their leadership position in the overall convergence switch market," said Kevin Mitchell, directing analyst, Service Provider Networks and Next Gen Voice, Infonetics Research. "For convergence switch packet voice applications, their revenue and port shipments continue to lead the pack well above the competition."

Recent reports issued by Synergy Research Group also recognized Sonus as a worldwide leader in carrier-class VoIP equipment. In their Q4 report, Synergy named Sonus the top provider of high-density VoIP gateways in both revenues and port shipments, and the leader in service provider VoIP solutions in total port shipments.

"In our most recent market share analysis, Sonus maintains its position as the dominant player in the market for high-end, carrier VoIP products," said Laurie Gooding, senior analyst, Synergy Research Group. "We believe that carriers continue to see packet voice as a strategic investment over traditional TDM solutions, and as a leader in this space, Sonus is helping to drive this critical transition."

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.

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