Qwest to Deploy Sonus Networks' Packet Voice Solutions in Next-Generation Voice Network

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Carrier Announces First Service Leveraging Sonus Platform: Qwest CyberVoice Interconnect

WESTFORD, Mass., March 13, 2001 -Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced that Qwest Communications International Inc. has selected Sonus' packet voice technology for deployment in its leading nationwide all-optical Internet Protocol (IP) network. Under terms of the multi-year, multimillion-dollar agreement, Qwest plans to use a range of Sonus' carrier-class packet telephony equipment as part of its development of services that blend Internet and voice technologies.

Qwest is building its next-generation voice network using Sonus' GSX9000 Open Services Switch, the INtelligentIP Softswitch, which Sonus gained through the recently completed acquisition of telecom technologies, inc., the PSX6000 SoftSwitch and the SGX2000 SS7 Signaling Gateway. Today, Qwest announced its first suite of services based on the Sonus platform, Qwest CyberVoice Interconnect, a wholesale Voice-over-Internet Protocol (VoIP) terminating service that enables providers to deliver clear, reliable voice calls over Qwest's nationwide broadband Internet network. Qwest is also evaluating the new Sonus-based infrastructure for a number of next-generation, collaborative applications. 

"Qwest takes a cutting-edge approach to technology, one that has propelled it to a leadership position in the broadband Internet communications industry," said Hassan Ahmed, president and CEO, Sonus Networks. "Sonus' voice-over-packet technology supports Qwest's development of the most technologically-innovative IP network in the world, and we look forward to working closely with Qwest to help it achieve its business objectives."

"By being one of the first nationwide carriers to incorporate packet voice technology into our core network, Qwest expects to gain significant cost efficiencies and provide next-generation IP-based voice and data services to our customers," said Mike Perusse, Qwest's senior vice president of engineering and technology. "Qwest CyberVoice Interconnect is just the first step. Qwest's strategy is to integrate Internet, voice and data applications to deliver truly converged, collaborative services, and our work with Sonus is advancing that strategy."

"We are very proud that Qwest has selected Sonus to help it build out its next-generation packet voice network, and we're tremendously excited about the range of services that Qwest will be able to deliver to its customers through this softswitch-based infrastructure," commented Anousheh Ansari, vice president and general manager of Sonus' INtelligentIP division.  

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice infrastructure products for the new public network. Sonus' solutions enable service providers to deploy an integrated network capable of carrying both voice and data traffic, and to deliver a range of innovative, new services. The Sonus Open Services Architecture (OSA) and award-winning Packet Telephony suite cut the time-to-market for competitive new service products, allowing carriers and third-party developers to expand marketshare and build important new revenue streams. Its highly scalable products fully interoperate with and extend the life and utility of today's public network. Sonus embodies in its management and staff decades of experience in developing carrier-class voice, data and multimedia solutions for implementation in the world's largest networks. Sonus, founded in 1997, is headquartered in Westford, 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 Sonus' Prospectus, dated January 12, 2001, and associated Registration Statement on Form S-4, filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements. These risk factors include, among others, the Company's ability to grow its customer base, dependence on new product offerings, market acceptance of its products, rapid technological and market change, integration risks relating to the acquisition of telecom technologies and manufacturing and sourcing risks.

INtelligentIP is a registered trademark and GSX9000, PSX6000, SGX2000 and Open Services Architecture are trademarks of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.