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Synergy Research Group and In-Stat/MDR Rank Sonus #1 in Several Key Carrier Packet Voice Segments for the Third Quarter

WESTFORD, Mass., November 17, 2003 – Sonus Networks (Nasdaq: SONS) today announced that market research firms Synergy Research Group and In-Stat/MDR have each reported that Sonus has extended its market leadership in the carrier-class packet voice equipment market.

"Sonus' increased leadership in this market is testament to the company's vision, our ability to execute, and especially our ability to understand and respond to changing customer needs," said Michael O'Hara, vice president, marketing, Sonus Networks. "Sonus continues to lead the charge as adoption of packet voice accelerates and is viewed as the vendor of choice as carriers look to leverage the advantages of packet technology."

Recent reports by Synergy Research Group revealed that Sonus Networks holds global leadership positions in several market segments. Synergy rankings for Sonus include:

• #1 in High Density VoIP Media Gateway revenuesf
• #1 in High Density VoIP Media Gateway port shipments
• #1 in VoIP Media Gateway port shipments, all densities 
• #1 in Carrier Packet Voice port shipments (includes VoIP Media Gateways, all densities, VoATM Media Gateways and Softswitches)
• #1 in Total Media Gateway port shipments (includes VoIP Media Gateways, all densities, and VoATM Media Gateways)

"In our most recent VoIP market analysis, Sonus increased its leadership position in providing high-density carrier class VoIP gateways to the telecom industry," said Jeremy Duke, founder and principal analyst, Synergy Research Group. "We believe that carriers are in full agreement that VoIP is a strategic investment to remain competitive as well as position their network assets for future revenue generation."

In-Stat/MDR released its third quarter market share analysis, which also shows Sonus as the leader in the carrier packet voice market. In-Stat/MDR rankings for Sonus include:

• #1 in High Density Voice Gateway port shipments
• #1 in High Density Voice Gateway revenues
• #1 in Total Voice Gateway port shipments, all product classes and densities

"With this quarter's results, Sonus has further solidified its position as a leading provider in the carrier packet voice market," said Norm Bogen, director, WAN Infrastructure and Services at In-Stat/MDR. "Sonus really pulled away from the competition in the third quarter, expanding its share dramatically, particularly in the High Density Voice Gateway segment. Sonus is one of the industry's pioneers, and their experience is reflected in the fact that they are consistently a leader when quarterly results are tallied."

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(TM)(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.