Sonus-Based Networks Carry Over 38 Billion Minutes of VoIP Traffic in the Second Quarter of 2005

CHELMSFORD, Mass., August 24, 2005 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, announced today that according to a quarterly report issued by industry research firm, iLocus, networks based on Sonus technology carried an estimated 38.2 billion minutes of VoIP traffic in the second quarter of 2005 (2Q05) alone, more than twice the amount of total VoIP traffic carried by any other equipment provider in the industry. Sonus also held the number one market share position in both national and international long distance traffic with 39.5% and 21.9% of the market respectively.

“Sonus' solutions are deployed by some of today's most successful network operators, and as a result, they have become a clear leader in the VoIP industry,” said Jahangir Raina, Director, iLocus. “The VoIP market has grown at an unprecedented rate in recent quarters, but the biggest opportunity still lies ahead. As more and more carriers build out new and existing VoIP networks, Sonus is well positioned to take advantage of the industry's push towards IP-based infrastructure solutions.”

VoIP solutions have moved beyond the "early adopter" phase, both in terms of the number of minutes currently being carried and the consumer profile of end users. According to the iLocus report, in total, an estimated 127.5 billion minutes of VoIP traffic was carried by service providers worldwide in 2Q05, a number that is expected to rise as carriers accelerate their migration plans and new players enter the market. To date, only 13% of all long distance minutes are carried over VoIP networks.

"Sonus has been a leading provider of VoIP solutions for over six years, offering our customers the cost-savings and service advantages that are prerequisites in today's networks. Some of the largest VoIP networks around the globe have been deployed leveraging Sonus' distributed architecture, which is designed to deliver carrier grade performance and is now being embraced by all types of service providers," said Hassan Ahmed, CEO of Sonus Networks. "We are committed to extending our leadership position in the industry by building on our success with our current customers, as well as breaking into new and emerging markets, particularly in the wireless realm and in international regions where many carriers are just beginning their migration."

The report by iLocus identified the wireless market as one of the prime growth opportunities for vendors in the VoIP industry, noting that IMS compliance on the part of equipment providers is important because most incumbents are asking vendors to conform to this standard. Sonus, which has been deploying industry leading SIP-based networks for the past six years, is a recognized leader in IMS and was recently honored with the Frost and Sullivan Award for Technology Innovation in recognition of Sonus' IMS solution.

Additional details on the iLocus report, entitled “VoIP Minutes: Q205 Update”, can be found at http://www.ilocus.com/voipminutes2q2005.htm.

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 comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services. Sonus' voice infrastructure solutions are deployed in service provider networks worldwide. Founded in 1997, Sonus 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, dated March 15, 2005, and the “Cautionary Statements” section of Sonus' Quarterly Report on Form 10-Q, dated August 8, 2005, both 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 impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities litigation against the company. 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 company and product names may be trademarks of the respective companies with which they are associated.