Neutral Tandem to Complete IP Voice Network Transformation with Sonus Networks

Next Generation IP Voice Network Now Serves 100 Markets in the United States

Westford, MA, February, 24, 2009 – Sonus Networks (NASDAQ: SONS), a market leader in IP communications infrastructure, today announced that Neutral Tandem, a leading provider of tandem services to wireless, wireline, cable telephony and VoIP providers, has entered the final phase of its next-generation network transformation which included the replacement of its nine TDM Circuit switches with IP compatible switches. These changes have reduced Neutral Tandem’s operating costs while increasing the levels of service Neutral Tandem offers to its customers.

Network Transformation Solutions

With SIP interconnections becoming the preferred interface method, and carriers moving away from existing TDM interconnections, Neutral Tandem is now carrying over six billion minutes of IP voice traffic a month, while reducing its operating costs and allowing for the introduction of new services to customers across the U.S.

"We have invested in the technology and architecture of the future to serve our customers’ needs as their managed tandem provider of choice,” said Surendra Saboo, chief operating officer of Neutral Tandem. "We could not compromise on service or availability, so we selected Sonus to transform our network. The robust, carrier-grade network running today offers the scalability, security and flexibility that our customers demand.”

Neutral Tandem is one of the leading facilitators of inter-carrier communications in the country, and has increased billable traffic more than five-fold since 2005. In 2006, Neutral Tandem made the decision to go all IP and now deploys Sonus’ IP switching technology to serve 100 markets across the United States carrying more than six billion minutes of traffic a month.

"Over the last five years, Neutral Tandem has established itself as one of the premier alternatives to ILEC tandem services in the country. It has taken a market leadership role in moving to an end–to-end IP based network to better serve its customers,” said Guru Pai, senior vice president at Sonus Networks. "We are proud to have such a successful and long term relationship with Neutral Tandem and we look forward to supporting their continued growth into new markets."

Neutral Tandem is deploying a full suite of Sonus' IMS (IP Multimedia Subsystem)-ready solutions, including the GSX9000™, the PSX™ Policy Server, and the Sonus Insight™ Management System. In addition, Neutral Tandem has deployed the Sonus Network Border Switch for enhanced security and direct IP-to-IP peering capabilities.

About Neutral Tandem, Inc.

Headquartered in Chicago, Neutral Tandem, Inc. is a leading provider of tandem services to wireless, wireline, cable and broadband providers. Founded in 2003, Neutral Tandem facilitates inter-carrier communications with a cost-effective alternative to the Incumbent Local Exchange Carrier (ILEC) network. Neutral Tandem's solutions build redundancy, security and operational efficiencies into the nation's telecommunications infrastructure. As of December 31, 2008, Neutral Tandem was capable of connecting approximately 391 million telephone numbers assigned to carriers. Telephone numbers assigned to a carrier may not necessarily be assigned to, and in use by, an end user. Please visit Neutral Tandem's website at: www.neutraltandem.com.

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 our Annual Report on Form 10-K for the year ended December 31, 2007 and all subsequent Quarterly Reports on Form 10-Q, 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 Company’s ability to align its cost structure with market conditions, 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 the impact the current global financial market conditions may have on the telecommunications industry. 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.

For more information, please contact:

US Media Relations
Shannon Breen
781-487-4607
sonus@racepointgroup.com

Lucy Millington
978-614-8240
lmillington@sonusnet.com