Appoints Telecom Industry-Veteran as Vice President of Engineering

CHELMSFORD, Mass., January 18, 2006 - Sonus Networks (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, today announced that Chuba Udokwu has joined the Company as its new Vice President of Worldwide Engineering. Mr. Udokwu brings over a quarter century of telecommunications engineering and product development experience to the Sonus executive team.

As Vice President of Engineering, Udokwu will be responsible for managing Sonus' industry-leading worldwide engineering team and guiding the company's technology development. Udokwu joins Sonus most recently from Cisco Systems, Inc. where he was responsible for managing the design, development and release of the company's Multiprotocol Label Switching (MPLS)-based software technologies. Prior to joining Cisco Systems, Udokwu lead the engineering team at Seranoa Networks (acquired by White Rock Networks). He has also held executive and senior level positions at Alcatel and Lucent Technologies.

“Sonus is recognized globally as an industry leader delivering the most innovative and reliable solutions for the transformation of the world's communication networks to VoIP,” said Bert Notini, president and chief operating officer. “Chuba's demonstrated leadership in driving the development and management of reliable next-generation technologies combined with his deep roots in the telecommunications industry will be invaluable to Sonus as we continue to introduce new IP-based telephony solutions."

“I am very excited to be joining Sonus Networks, a company that has been instrumental in leading the evolution to VoIP. Sonus pioneered the development of carrier-class VoIP solutions, which has helped drive VoIP into the mainstream,” said Chuba Udokwu. “I look forward to leading Sonus' technology development as network operators globally embrace VoIP as the foundation for their communication networks.”

Mr. Udokwu received his Bachelor and Master of Science degrees from Columbia University School of Engineering

“I want to personally thank Paul Jones for his many contributions to Sonus over the last five years. His leadership and expertise have helped to build Sonus into the recognized technology leader in VoIP. I have every confidence that Chuba will build on our strong technology foundation to drive Sonus' future growth,” concluded Notini.

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 Chelmsford, 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 the “Risk Factors” section of Sonus' Annual Report on Form 10-K, dated March 15, 2005, and the “Cautionary Statements” section of Sonus' Quarterly Report on Form 10-Q, dated November 8, 2005, both filed with the SEC, which identify 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 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. All other company and product names may be trademarks of the respective companies with which they are associated.