Building on Recent Success in Europe, Sonus Networks Opens New Operations Center in Prague; Sonus Opens New Regional Office to Support Burgeoning VoIP Opportunity in EMEA.

SWINDON, U.K. -- Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, announced today that it has opened a regional support center in Prague, Czech Republic to address and service the growing market opportunities for next generation voice solutions across Europe. According to a recent industry report issued by Infonetics Research, VoIP deployments in the Europe, Middle East, and Africa (EMEA) region are expected to grow faster than in either the North American or Asia-Pacific markets. Sonus, which established an early foothold in the EMEA region and has been deployed in some of the world's most advanced IP-based networks, is expanding its presence and professional services capabilities in Europe in order to support its growing business in the EMEA market where Sonus solutions offer network operators the ability to rapidly deploy a broad range of revenue-generating, enhanced services.

"Carriers in Europe are beginning to embrace the benefits of IP-based solutions for voice networks, and we expect that 2006 will be the time when many major carriers aggressively begin the long investment cycle and service rollout," said Kevin Mitchell, Principal Analyst, Infonetics Research. "Sonus has established itself as a leader in the VoIP market, with deployments with some of the largest carriers in the world. By expanding its presence in Europe, Sonus can leverage their leadership and experience to win customer accounts in this high-growth region."

Sonus currently has a regional sales and support presence throughout several countries in Western Europe, including the United Kingdom, France and Germany. The establishment of an office in the Czech Republic is in direct response to increased demand for Sonus solutions in EMEA.

"Sonus is committed to having a local presence in the regional markets that have demonstrated enthusiasm for the power of IP-based technologies to reshape today's telecommunications networks," said Joop van Aard, vice president of sales, EMEA, Sonus Networks. "Sonus established an early presence in EMEA by building a world class sales, research & development, and operations center to support the Company's international customers. Now, encouraged by the growth we're witnessing throughout Europe, we are excited to build a stronger support presence and reinforce our commitment to serving this growing market."

Sonus' support center will be located at City Empiria, Na Strzi 65 in Prague, Czech Republic.

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. All other company and product names may be trademarks of the respective companies with which they are associated.