Sonus To Remain Listed on NASDAQ Pending Review by Nasdaq Board

WESTFORD, Mass., June 26, 2007 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, today announced that the Nasdaq Board of Directors has called for review the decision of the Nasdaq Listing and Hearing Review Council (the "Listing Council") dated May 9, 2007 and granted a stay of the delisting of the Company's securities pending further review by the Board in July. The Listing Council previously had granted Sonus through June 26, 2007 to regain compliance with the requirements for continued listing on the NASDAQ Global Select Market. The Company's securities will remain listed on the NASDAQ Global Select Market pending further action by the Nasdaq Board.

The Company is working diligently to file its Quarterly Reports on Form 10-Q for each of the quarters ended June 30, 2006, September 30, 2006 and March 31, 2007 and its Annual Report on Form 10-K for the year ended December 31, 2006 as soon as possible. With these filings, Sonus believes that it will regain compliance with the requirements for continued listing.

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 for the period ended March 31, 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 restatement of its historical stock option granting practices and accounting including regulatory actions or litigation; whether the Company will remain listed on the NASDAQ Global Select Market; 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.

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.