Company contacts:

Hassan Ahmed Assumes Position of Chairman and Chief Executive Officer; Bert Notini Joins Sonus as President and Chief Operating Officer

CHELMSFORD, Mass., April 6, 2004 – Sonus Networks (Nasdaq: SONSE), a leading provider of voice over IP (VoIP) infrastructure solutions, today announced that Bert Notini has joined Sonus as president and chief operating officer (COO), reporting to Hassan Ahmed.  Ahmed will continue to serve as chief executive officer (CEO) and, in addition, has been appointed chairman of Sonus’ board of directors.  Rubin Gruber, a founder of the company, has been named chairman emeritus, and will continue to focus on business development, reporting to Ahmed. 

Notini brings strong leadership and perspective to Sonus, combining broad operations experience in global technology companies with an extensive background in the financial and legal fields.  He most recently served as chief financial officer (CFO) of Manufacturers Services Limited. 

As CEO and chairman, Ahmed will focus on driving strategic initiatives for the company, including technology development, business development and customer relationships.  Reporting to Ahmed, Notini will lead the company’s day-to-day operations.  Notini will also assume responsibilities for the financial operations of the company as Stephen Nill, Sonus’ CFO, today transitions to a new role as vice president of business operations.  Notini will serve as head of financial operations until a new CFO is named. 

“Adding resources to our executive management team is important as we position Sonus for our next phase of growth,” said Ahmed.  “We considered a number of qualified candidates from across the industry over the past year.  We have worked closely with Bert since he joined our board a year ago, and we are very pleased to bring someone of his caliber onto our management team.  Bert possesses considerable experience in managing the operations of large global businesses, and he will be an invaluable asset to Sonus.”

“I am pleased to be joining the Sonus executive team,” commented Notini.  “Sonus has long been at the forefront of the next-generation voice market, and is positioned to be one of the major players as this industry continues to develop.  I look forward to developing our operations and reaffirming Sonus as a best-in-class organization.”

Notini has been a member of Sonus’ board of directors since March 2003 and will continue to serve as a director on the board.  He has resigned his position as chairman of the company’s audit committee, which now comprises non-employee directors Edward Anderson, Paul Ferri and Paul Severino.

Since October 2000, Notini has served as the CFO of Manufacturers Services Limited, a global electronics and supply chain services company.  Previously, Notini spent five years at Wang Global, where he held the positions of executive vice president, corporate development and administration, and general counsel.  Wang Global was acquired by Getronics NV in June 1999 and Notini served as executive vice president of Getronics until February 2000.  Prior to joining Wang in 1994, Notini was a partner at the Boston-based law firm Hale and Dorr LLP.  Notini holds a B.A. from Boston College, an M.A. from Boston University, and a J.D. from Boston College Law School.  Notini also serves as a director of ePresence, Inc.

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 Open Services ArchitectureÔ (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking and tandem switching, residential and business access, network border switching and enhanced services. Sonus’ voice infrastructure solutions, including media gateways, softswitches and network management systems, are deployed in service provider networks worldwide.  Sonus, founded in 1997, is headquartered in Chelmsford, Massachusetts.  Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain projections or other forward-looking statements regarding future events or the future financial performance of Sonus 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 the “Cautionary Statements” section of Sonus’ Quarterly Report on Form 10-Q, dated November 10, 2003 and 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, uncertainties regarding the Company’s ability to complete the audit and file its Annual Report on Form 10-K/A for 2003 and future periodic reports, risks as to the SEC’s investigation of these or other matters, unforeseen issues encountered in the completion of the audit, uncertainties regarding the extent to which prior period financial statements will be restated, the continued adverse effect of developments in the telecommunications industry, Sonus’ ability to grow its customer base, dependence on new product offerings, market acceptance of its products, competition from large incumbent vendors, rapid technological and market change and manufacturing and sourcing risks.  In addition, 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.  Open Services Architecture, GSX9000, Insignus and Sonus Insight are trademarks of Sonus Networks.  All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.