Innovative Companies from Across the Communications Industry Join the Sonus Interoperability Certification Program

WESTFORD, Mass., March 22, 2007 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that some of the industry’s most innovative companies have joined the Sonus Interoperability Certification Program at the University of New Hampshire InterOperability Lab (UNH-IOL), which is designed to help promote successful interoperability in multi-vendor networks. The Sonus Certification program was launched as part of the Open Services Partner Alliance, the industry’s pioneer Session Initiation Protocol (SIP) interoperability testing organization, to advance further network operators’ ability to deploy solutions from multiple vendors within their networks.

Wave7 Optics, a leading supplier of fiber-to-the-premises (FTTP) equipment for residential and business services, is the first company to successfully complete the Sonus Interoperability Certification Program.  Wave7 Optics’ product portfolio features a variety of architectural options based on IP and Ethernet standards for "triple-play" voice, video and data services.  The company's patented Last Mile Link and Trident7 systems are rapidly gaining market share around the world with service providers in the IOC, CLEC, cable MSO, municipal, utilities and real estate development categories.  For more information, please visit Wave7 Optics’ website:  www.Wave7Optics.com

DIGITALK, which provides an NGN Application Server with service-ready applications including Broadband Telephony, IP Virtual Office and Prepaid Calling Cards, has also enrolled in the Sonus Interoperability Certification Program. DIGITALK solutions are supported by the MultiService Platform, a complete service delivery environment, enabling very rapid rollout of new services.

The UNH-IOL is an independent test lab with between $20 million and $30 million in equipment devoted to testing and debugging products for interoperability and conformance to standards in various facets of networking. The UNH-IOL applies a collaborative membership model that distributes the cost of building and running test beds and test equipment to meet the most rigorous demands of today’s diverse enterprise and service scenarios. The Sonus Interoperability Certification Program leverages the UNH-IOL to conduct extensive testing and streamline the delivery of Session Initiation Protocol (SIP)-based products and services into the rapidly evolving IP-based voice market.

“We’re excited that some of the industry’s most innovative and dynamic companies have enrolled in the Sonus Interoperability Certification Program,” said Vikram Saksena, chief technology officer, Sonus Networks. “Our goal is to help our customers build the most robust networks possible, streamlining their networks from an operational standpoint and helping them to deliver new services to their customers. The Certification Program is a big step forward for promoting interoperability across the industry, and Sonus is proud to team with UNH-IOL, an organization with proven expertise and leadership in this area.”

“Our goal is to leverage our extensive expertise testing next generation voice equipment to become the Industry’s premiere testing center for SIP-based products and services,” said Timothy Winters, UNH-IOL Technical Manager. “The Sonus Certification Program has attracted some of the most interesting and unique vendors in the communications industry today, and we’re committed to assisting the rapidly growing VoIP marketplace by leveraging our unique testing capabilities.”

Sonus Networks and the UNH-IOL will host an information session for interested companies at this year’s Spring VON 2007 Conference in San Jose, CA, Thursday, March 22, 2007, in Room J1 at 9:00 am PT and 11:30 am PT.

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, whetherthe Nasdaq Listing Council will continue the delisting stay or grant an extension or that the company's securities will remain listed on the NASDAQ Stock Market, 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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