Proliferation of IP-Based Networks Increases Carrier Demand for RobustSecurity Solutions

WESTFORD, Mass., Jan. 31 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice-over-IP (VoIP) infrastructure solutions, announced today the latest release of its Network Border Switch (NBS), offering network operators one of the industry's most robust security solutions for maintaining the integrity of their networks. The latest version of the NBS is available for both the GSX9000(TM) Open Services Switch, and the smaller form factor GSX4000(TM), providing carriers with a right-sized, flexible solution to meet their security needs within the framework of their IP Multimedia Subsystem (IMS)-ready architecture.

"There are three primary market drivers necessitating enhanced network security features beyond typical Session Border Controllers (SBCs). First, network operators looking to grow their markets by expanding their presence or offering new services are peering with other networks on a much larger scale. Secondly, the recent flurry of mergers and acquisitions among network operators has created heterogeneous networks that need to be integrated in a secure manner. Lastly, more and more network operators are responding to consumer demand for services that connect to the public Internet, which creates a unique set of obstacles," said Steve Edwards, chief marketing officer, Sonus Networks. "Sonus' Network Border Switch allows our customers to address these challenges by delivering a complete, natively IP peering and security solution."

The latest release of the NBS includes increased Denial of Service protection for carrier peering and rogue Real-time Transport Protocol (RTP) protection, including attack detection, notification and diagnosis. In addition, the sophisticated monitoring, trace, and statistical analysis tools have been further enhanced to help network operators evaluate service level performance and more quickly perform security event identification, logging, and mitigation.

Unlike traditional peering and security products such as SBCs, Sonus' NBS delivers a unique solution that combines session control, PSTN gateway services and security into a single, high performance, carrier-class system. Sonus' NBS, which is deployed in some of the world's largest VoIP networks, is a purpose-built, IP-based solution that allows network operators to leverage the system's sophisticated media handling functionality; extensive IP signaling options that include SIP, SIP-T and H.323; network address and port translation features that protect the privacy of the internal private network topology; session-based firewall functionality; and advanced traffic control features.

"As IP-based communications continue to displace legacy network solutions, session control and related issues, such as security, become more pervasive problems for service providers to solve," said Joe McGarvey, principal analyst with Current Analysis. "Sonus, which has long been a pioneer in IP solutions that meet the rigorous demands of large network operators, continues to evolve its NBS product line to empower service providers to address these increasingly complex and strategically important session control requirements."

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 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 dated May 8, 2006, 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 announced review of its historical stock option grants and accounting, including any potential impact on the Company's financial statements or results, any tax liabilities or penalties, the Company's inability to timely report with the Securities and Exchange Commission, the Company's potential inability to meet NASDAQ requirements for continued listing, potential investigations, regulatory actions or litigation arising out of the review or any restatement; 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.

The product information in this press release is for informational purposes only and is subject to change at Sonus' sole discretion without notice. Sonus has no obligation or commitment to develop or deliver any future release, upgrade, feature, enhancement or function described in this release. The information is provided "AS IS," with all faults, and without any warranties whatsoever, express or implied, including, but not limited to, warranties of merchantability, performance, or fitness for a particular purpose.

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