Sonus Donates Technology To Zilina Institute Of Next Generation Networks

WESTFORD, MA and STAINES, UK., June 5, 2008 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in IP communications infrastructure, today demonstrated its commitment to the development of the Eastern European telecommunications industry by providing IP infrastructure hardware and software to the Zilina Institute of Next Generation Networks (INGN) in the Slovak Republic. The INGN, which is 66 per cent owned by Slovak Telekom works closely with the University of Zilina, to drive innovation and development of next-generation networks in the region and beyond.

The Slovak Republic has seen rapid growth of the relatively small telecoms industry in recent years and is set to position the country at the forefront of telecommunications development as they offer new services to home and business subscribers. In conjunction with the Faculty of Electrical Engineering, the Faculty of Management Science and Informatics and the Faculty and Operation of Transport and communication at the University of Zilina, the INGN facilitates a cohesive approach to the development of the regions telecommunications infrastructure.

"We wanted to gain access to Sonus IP-based infrastructure technology as it supports the some of the world's largest carrier networks, in the most sophisticated and demanding markets. The technology is proven as one of the best in class and these are the standards we want to develop and implement for our region, said Professor Milan Dado, chairman of INGN. For the region to gain a competitive edge in a connected and expanding European market, we rely on donations to facilitate our research and development. This donation from Sonus Networks to the Institute demonstrates their commitment to the growth and development of our industry."

"We are pleased with the recent addition of Sonus platform to INGN's laboratories. This supports our aim to develop INGN's lab into leading multi-vendor IP and NGN test environment within Central and Eastern Europe", commented Peter Helexa, director of strategy and new business development, and member of the supervisory board of INGN.

For the next-generation network research project, Sonus provided multiple solutions including the GSX 4000 Gateway and Network Border Switch. Sonus also provided the Sonus Insight Element Management System to provide a comprehensive graphical user interface to manage all of the components of the Sonus packet telephony solution.

"Sonus Networks is pleased to offer the INGN the support it needs in its drive to further the research and development of next-generation networks. Sonus is committed to supporting the development of new and emerging technologies in the region and looks forward to working closely with the Institute to champion innovation," said Tony Morrish, vice president, EMEA at Sonus Networks.

About Sonus Networks

Sonus Networks, Inc. is a market leader in IP communications infrastructure 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 Westford, 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 Item 1A "Risk Factors" of Sonus' Quarterly Report on Form 10-Q for the period ended March 31, 2008, filed with the SEC, which identifies 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 and uncertainties associated with the Company's restatement of its historical stock option granting practices and accounting including regulatory actions or litigation; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities and patent 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, except as required by law.

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