Sonus Ranked Number One in Analyses by Cahners In-Stat, Infonetics and Synergy Research Group; Company Continues to Gain Market Share in Highly Competitive Segment

WESTFORD, Mass., February 26, 2001 - Sonus Networks, (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced that it has again been named worldwide market share leader for carrier-class packet voice switching equipment.  Reports issued recently by industry research firms Cahners In-Stat Group, Infonetics Research and Synergy Research Group confirm Sonus' leadership position for both the fourth quarter of 2000 and for the full year.

"The numbers reported by Cahners, Infonetics and Synergy reflect the continued strong demand for our solutions, and underscores the momentum we have gained in the market," said Stephen Collins, vice president, marketing, Sonus Networks.  "We are very proud that our customers have selected us as their partner in building out their next-generation voice infrastructures, and we are pleased that these respected research firms have recognized us as an industry leader as well."

Cahners In-Stat Group unveiled its fourth quarter market share report today, with data showing Sonus as continued leader in purpose-built carrier VoIP gateways, in both ports and revenues.  According to the Cahners report, Sonus expanded its lead by a significant margin in the last quarter and over the year, while competitors' shares declined. 

"A number of companies are talking about delivering carrier class VoIP gateways, and others are just now starting to deploy units," said Norm Bogen, director, WAN Infrastructure and Services, Cahners In-Stat Group.  "Sonus is clearly the market segment leader, having commercial VoIP shipments for 12 months, and continues to widen the gap."

Last week, Infonetics Research launched its quarterly worldwide market share and forecast service, "Next Gen Voice Products," which covers various market segments, including voice/data switches.  In this report, Infonetics named Sonus the leader in revenues for voice/data switching solutions, a sector viewed as one of the fastest growing in the networking industry.  

"Start-ups are clearly the innovators in the market for next-generation voice/data switching, and Sonus has built a solid lead in this segment," said Infonetics Research analyst Kevin Mitchell.  "Sonus has gained significant ground during the year, winning close to half of the revenues for the 2000 voice/data switch market through wins with marquee customers and overall execution on their strategy."  

Synergy Research Group also recognized Sonus as the top performer in its fourth quarter and year-end 2000 report on voice over IP (VoIP) equipment market share.  Synergy ranked Sonus the number one provider of both carrier-class VoIP media gateways and VoIP/data media gateways.  In the Synergy report, Sonus also vaulted to the leading position for worldwide VoIP ports across all product classes, a segment that includes not only the purpose-built carrier-class gateways, but also the PC-based, RAS-based and TDM-based VoIP solutions that have been on the market for a number of years.

"Q4 was significant for both the emerging packet voice market and for Sonus.  VoIP has moved away from being just an add-on functionality for long distance toll bypass, to being the migration path for legacy TDM voice networks," says Jeremy Duke, founder and principal analyst, Synergy Research Group.  "The market shift, coupled with Sonus' first to market advantage, propelled Sonus' port shipment market share beyond all other established and start-up manufacturers in the packet voice equipment market, a market share shift that was sudden, and surprising."

Continued customer acceptance of Sonus' Packet Telephony suite, including the award-winning GSX9000 Open Services Switch, has propelled Sonus to the leading position in the market for next-generation packet voice solutions.  The GSX9000 is a key component of the Sonus Open Services Architecture, a system that delivers the scalability, reliability, interconnectivity and voice quality required for deployment in global service provider networks.  Moreover, the comprehensive 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.

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 Architecture (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 marketshare 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' Prospectus, dated January 12, 2001, and associated Registration Statement on Form S-4, 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, integration risks relating to the acquisition of telecom technologies and manufacturing and sourcing risks.

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