Sonus? Scalability, Reliability and Accelerated Time to Market Noted as Key Motivators To Selection

WESTFORD, MA and CHICAGO, IL, December 18, 2008 – Sonus Networks, (Nasdaq: SONS), a market leader in IP communications infrastructure, today announced that Peerless Network LLC, a provider of services that simplify interconnecting voice and data traffic across disparate networks, has standardized on Sonus’ full line of IP solutions for its next-generation network. The Sonus solution enables Peerless to quickly deploy its next-generation network to link traffic across TDM and IP networks. With the Sonus solutions in place, Peerless can provide high levels of quality of service and reliability to its rapidly expanding customer base.

Peerless chose the complete Sonus IP-based session control network as part of the company's plan to rapidly grow their market presence while offering best-in-class tandem termination, switched access and IP peering services. Peerless has stated aggressive growth plans, expecting to expand into at least a dozen markets by early 2009, increasing their market presence three-fold.

“As we expand into established markets, it is imperative that we differentiate our service offering to attract new customers, while at the same time launch our new markets as quickly and cost effectively as possible,” said John Barnicle, CEO at Peerless. “After a rigorous evaluation, Sonus met our requirements. They had the right end-to-end IP solution that would allow us to scale our network to meet our rapidly growing subscriber base combined with the security and reliability we demand for our customers.”

“Peerless Network is looking to exceed their customer needs through an innovative set of service offerings,” said Mohammed Shanableh, vice president, worldwide sales at Sonus Networks. “The complete Sonus IP solution that Peerless Network selected for its next-generation network will provide a robust IP platform to support advanced session control capabilities and provide the flexibility needed to quickly expand its presence in new markets. Sonus can help emerging operators to get into service quickly, securely and cost effectively, to rapidly realize a return on their infrastructure investments.”

Specifically, Peerless has deployed the complete Sonus solution, including the Sonus GSX9000™ Media Gateway, the Sonus PSX™ Call Routing Server, Sonus SGX™ Signaling Gateway, and the Sonus NBS™ Network Border Switch as the session border controller for IP Access and Trunking.

About Peerless Network LLC

Peerless Network is a fully funded, privately held company focused on simplifying the interconnection process for other telecommunications service providers via a wide range of innovative services. Based in Chicago, the company currently delivers services in Chicago, New York, Philadelphia and St. Louis. Peerless Network expects to be in a dozen major markets by early 2009 – increasing market presence three-fold. More information is available at www.peerlessnetwork.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.