Largest Cable Operator in Belgium Selects Sonus' Network Border Switch to Drive Enterprise Voice Services

WESTFORD, Mass., and Staines, UK, August 25, 2008 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in IP communications infrastructure solutions, today announced that Telenet, a leading provider of media and telecommunications services and the largest cable operator in Belgium, will use Sonus technology to offer businesses across the country secure and reliable access to next generation IP voice services. Telenet will extend the services of its broadband network to provide Belgian enterprises with a new and cost effective option to receive their office telephone services.

"Telenet has established one of the most recognized brands and delivered premier services to homes across Flanders and to businesses across the whole of Belgium for many years," commented Peter Michiels, SVP Networks and System Engineering at Telenet. "As we offer new services to our more demanding business customers, it is critical to our success to choose a solution that is scalable, reliable, manageable, secure and integrates into our existing infrastructure. The technology from Sonus was the only solution to satisfy our rigorous selection criteria across all measures."

The Sonus Network Border Switch (NBS) is a key component of Telenet's plans, assuring business customers the most secure communications. Sonus' NBS will enable Telenet to intelligently route voice calls and provide enhanced transcoding services, ensuring interoperability. Telenet's business services offer will provide enterprises across Belgium a cost effective and secure alternative to legacy telephone services. The Sonus NBS will allow Telenet to expand its offer to include additional IP based business voice services and next generation application integration.

"Sonus will partner with Telenet in the delivery of new services as its network, which supports over 3.2 Million RGUs, expands to reach advanced business customers," said Tony Morrish, vice president, EMEA, at Sonus Networks. "Sonus is committed to building innovative solutions for the cable industry that are global in their interoperability. I believe this partnership is further evidence of the growth Sonus has experienced in Europe and our growing success in serving cable providers around the world."

The Sonus Network Border Switch's provides Telenet with an integrated approach to security, as well as a better way to manage and secure its network as it migrates telephony traffic from legacy TDM to voice over IP. Based on the market-leading Sonus GSX9000 platform, the Network Border Switch is a carrier-class solution that provides IP-to-IP border control and PSTN media gateway capabilities, integrating security, session and media control. These are the capabilities that assure secure connections to businesses' PABX systems and make it more cost effective to provide a single connection for voice and data traffic. As Telenet scales its services to reach businesses, Sonus' NBS has a proven record of allowing carriers to grow quickly to meet demand and, more importantly, to offer additional new services.

About Telenet

Telenet is a leading provider of media and telecommunication services. Its business comprises the provision of cable television, high speed internet and fixed and mobile telephony services, primarily to residential customers in Flanders and Brussels. In addition, Telenet offers services to business customers across Belgium under the brand Telenet Solutions. Telenet is listed on the Euronext Brussels Stock Exchange under the ticker symbol TNET.

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 June 30, 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; actions that may be taken by significant shareholders; 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.

Sonus is a registered trademark of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.