In-Stat/MDR and Synergy Research Group Rank Sonus #1 in Several Carrier Packet Voice Segments for Q2 2004

CHELMSFORD, Mass., August 31, 2004 – Sonus Networks (Pink Sheets: SONS) today announced that it has been named the market share leader in several segments of the carrier voice over IP (VoIP) equipment market by industry research firms In-Stat/MDR and Synergy Research Group.

“Sonus has been a consistent and long standing leader in carrier-grade VoIP solutions, and we’re excited that respected industry research firms like Synergy and In-Stat have reaffirmed our #1 position in key segments of this highly competitive market,” said Steve Edwards, chief marketing officer and general manager, EMEA, Sonus Networks. “As major telecommunications bellwethers such as AT&T turn to Sonus as the enabler of their next-generation VoIP networks, momentum behind the company and the VoIP market as a whole continues to accelerate.”

In-Stat/MDR released its second quarter market share report, which shows Sonus is the leader in worldwide high-density voice gateway ports and revenue, as well as total voice gateway ports.

“VoIP deployments were once limited to a few early adopters, but over the past several quarters, we’ve seen the number of major carriers embracing VoIP technology at previously unmatched levels,” commented Norm Bogen, director, networking, In-Stat/MDR. “By providing high quality and consistently reliable carrier-grade solutions, Sonus Networks has played a significant role in driving adoption among carriers from across the globe.”

Similarly, recent market analysis for Q2 2004 by Synergy Research Group showed that Sonus holds global leadership positions in carrier packet voice ports, media gateway ports (all densities), high-density gateway revenues and high-density gateway ports.

“The most exciting trend we tracked this quarter was the number of carriers that announced the decommissioning of existing TDM switches in favor of VoIP infrastructure solutions,” said Jeremy Duke, founder and principal analyst, Synergy Research Group. “For example, in Q2, Sonus customer Global Crossing announced the decommissioning of a core circuit switch with plans to replace additional TDM switches with VoIP in the second half of 2004 and 2005. Sonus ended the quarter on strong footing and is positioned to remain a strong leader in carrier VoIP with such marquee customer deployments around the globe including AT&T, NTT, T-Systems, Softbank Broadband and Qwest, among others.”

The In-Stat/MDR and Synergy reports provide market share estimates developed by In-Stat/MDR and Synergy respectively.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice over IP (VoIP) infrastructure solutions for wireline and wireless service providers. With its Open Services ArchitectureTM (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking and tandem switching, residential and business access, network border switching and enhanced services. Sonus' 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 Chelmsford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain forward-looking statements regarding future events 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 “Risk Factors” section of Sonus’ Annual Report on Form 10-K/A dated July 28, 2004 and filed with the SEC, and the “Cautionary Statements” section of Sonus’ Quarterly Report on Form 10-Q, dated August 20, 2004 and filed with the SEC, which identify important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include, among others, the possibility that Sonus may not be re-listed on the The Nasdaq National Market and risks associated with the pending securities litigation and SEC investigation. 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.

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