Sonus Networks Integrates Leading IMS-Ready Infrastructure with GSM Access Technology from RadioFrame Networks

WESTFORD, Mass., and Orlando, FL, March 28, 2007 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, and RadioFrame Networks, a leader in IP-based picocell and femtocell solutions for the mobile marketplace, announced today at CTIA Wireless 2007 that the two companies are working together to enable broadband-cellular converged solutions to deliver voice services and multimedia applications to mobile handsets by leveraging customer-premise GSM access technologies, such as picocells and femtocells.  The joint solution will enable mobile network operators to optimize the performance of their networks, extend the reach of their coverage, increase capacity and reduce operating costs.

“Sonus has been actively engaged in building an ecosystem of world-class vendors that are pioneering the new market for broadband-cellular converged solutions through GSM access technologies,” said Vikram Saksena, chief technology officer, Sonus Networks. “Sonus’ IMS-ready network infrastructure coupled with solutions from companies like RadioFrame Networks opens up a new set of opportunities for wireless network operators that are committed to improving service to their customers while reaping significant operational benefits.”

“Although cell phones were once used primarily for communication on-the-go, today more and more people use them as a primary telephone service, at home or in the office,” said RadioFrame Networks President and Chief Executive Officer Jeff Brown. “Coupling RadioFrame Networks’ picocell and femtocell base stations with Sonus’ core network infrastructure expands the reach and usability of cell phones, while delivering significant benefits to the network operators. By partnering together, Sonus and RadioFrame Networks are working to deliver a highly scalable, carrier-class experience with this exciting new technology.”

About RadioFrame Networks, Inc.

Headquartered in Redmond  , Washington , USA , RadioFrame Networks, Inc. is the leader in modular radio solutions for telecom operators. RadioFrame deploys cost-effective radio access via flexible and efficient software driven base stations. Unlike traditional approaches from vendors offering proprietary, single-technology equipment, RadioFrame Networks offers an agile, multiple-technology, future-proof solution that integrates into existing networks, increases capacity and reduces operating costs and capital expenditures. For more information, please visit the company's Web site at www.radioframenetworks.com.

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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