Sonus Networks Addresses Burgeoning Russian Market Through First Partnership With the Leading Russian Systems Integrator

NVision Group Delivers Sonus Networks IMS-Ready Architecture

CHELMSFORD, Mass., July 5, 2006 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, and NVision Group, a market-leading Russian system integrator, today announced that the two companies have entered into a cooperative marketing and teaming agreement, whereby NVision Group will promote Sonus' industry-leading IP Multimedia Subsystem (IMS)-ready architecture and work with Sonus to pursue opportunities with service providers throughout Russia and the members of the Commonwealth of Independent States (CIS), which includes Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Ukraine, and Uzbekistan.

“By leveraging relationships with regional companies that understand the nuances of specific geographies and business climates, Sonus is broadening its global reach and penetrating new markets,” said Joop Van Aard, Sonus Networks. “NVision Group is a trusted and respected system integrator in a region that can benefit from the deployment of IP-based voice solutions.”

“NVision Group's goal is to help our customers deliver the most value from their technology investments,” said Andrei Zuzin, 1st Deputy General Director of NVision Group. “We have successful partnerships with national telecom and public clients, and by entering into an agreement with Sonus, we're able to provide our customers with a network architecture that is quick to deploy and scales cost-efficiently.”

“Russia and the surrounding countries are still in the early stages of evolution to next generation voice solutions, but the market opportunity is rich. By employing a strategic reseller partnership with NVision Group, Sonus is able to establish an early presence, laying the groundwork for future growth,” said Teresa Mastrangelo, Principal Analyst with Broadbandtrends.com.

About NVision Group

NVision Group is a market-leading Russian system integrator that is uniquely focused to align the business of national companies with the power of best-in-class IT, networking and telecom solutions. NVision Group brings clients value-added consulting and system integration services, from planning of the network, to strategic consulting, system design, integration, and development. Our professionals leverage leading-edge technologies and business experience to drive clients' business process improvements and increase the value of clients' investments in information technologies. Founded in 2001, NVision Group is headquartered in Moscow, Russia.
http://www.nvg.ru/eng.

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 14, 2006 and Quarterly Report on Form 10-Q, dated May 8, 2006, 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. All other company and product names may be trademarks of the respective companies with which they are associated.