Provider of Wholesale Long Distance Voice Service for Facilities and Non-Facilities Based Communications Providers Chooses Proven Leader in VoIP Industry

CHELMSFORD, Mass., September 1, 2005 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, announced today that ANI Networks, Inc., a provider of long distance services for the resale and facilities-based wholesale communications markets, has selected solutions from Sonus for the foundation of its next generation network deployment. Sonus solutions will initially be deployed in Los Angeles and New York City in Q4 2005, with future plans to rollout in additional major market areas both domestically and internationally by Q2 2006.

"For our customers, choosing the right carrier to move their traffic is integral to the success of their business. As a result, we only partner with equipment providers that have a proven track record in reliability and high performance. Sonus is a proven leader in the market with a history of successful carrier network deployments throughout the world," said ANI Networks President, Joe Koppy. "The true benefit to our resale and carrier clients will be rock solid performance coupled with some of the most aggressive pricing structures in the wholesale industry today."

ANI Networks will deploy a suite of Sonus' solutions including the Sonus GSX9000^TM Open Services Switch, PSX^TM Call Routing Server, SGX^TM Signaling Gateway, and the Sonus Insight^TM  Management System. By implementing a Sonus-based network, ANI Networks will also be able to offer a comprehensive portfolio of enhanced services offered through Sonus' Open Service Partner Alliance (OSPA), one of the industry's largest interoperability programs. Sonus was a pioneer in the application of session initiation protocol (SIP) for the delivery of enhanced services, and the OSPA program will provide ANI Networks with a rapid and cost-efficient approach for rolling out next-generation services.

"The business benefits of an IP-based architecture for service providers like ANI Networks are illustrated in the rapid growth and success of the long distance VoIP market. Last quarter alone, research group iLocus reported that nearly 95 billion minutes of long distance traffic was carried over VoIP networks, and Sonus held the number one market share position in both the national and international long distance market segments," said Hassan Ahmed, CEO of Sonus Networks. "Sonus has led the drive in the adoption of IP-based solutions for long distance network providers by not only meeting, but exceeding the quality, scalability and reliability expectations service providers demand in order to service their valued customers."

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, Inc. Sonus GSX9000 Open Services Switch, PSX Call Routing Server, SGX Signaling Gateway, and the Sonus Insight Management System are trademarks of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.