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New Jersey-based Service Provider to Deliver Packet Voice Services to Enterprises

WESTFORD, Mass., and PARSIPPANY, N.J., July 17, 2001 – Sonus Networks (Nasdaq: SONS) and Exario Networks today announced that they are collaborating in the development of Exario's nationwide next-generation packet voice network. Exario is implementing Sonus Networks' GSX9000 Open Services Switch and the PSX6000 SoftSwitch to support a range of voice/data services to enterprise customers. 

"As a leading provider of private IP voice and data networks for enterprises, we required a solution that provides the highest levels of reliability, quality and flexibility," said Nathan Stratton, chief technology officer, Exario Networks. "After evaluating the technology alternatives available, Sonus emerged as the only vendor that is delivering field-proven solutions that will further Exario's advanced voice service offerings."

Leveraging the Sonus platform, Exario will deliver business access services to enterprise customers via PBX (Private Branch Exchange) connectivity. In this application, Exario will provide connectivity for business customers' existing PBXs to the packet voice network by directly linking them to Sonus' award-winning GSX9000. By connecting PBXs to the packet voice infrastructure, Exario can offer clients the same standard local services that they have enjoyed in the circuit-based environment, including directory services, emergency 911, direct dialing, call transfer, call privacy, call screening and more. Additionally, Exario can seamlessly connect business users working at home or in small offices to connect to the packet voice network via integrated access devices (IADs).

"By deploying packet-based voice technologies, Exario can deliver both traditional and new revenue-generating enhanced services more easily and rapidly than ever before," said Hassan Ahmed, president and CEO, Sonus Networks. "We are extremely pleased to have been selected by Exario as a strategic partner in building out its next-generation voice infrastructure, and are committed to helping them enhance their business proposition to enterprise customers."

Exario has begun deploying the Sonus solutions in select cities in its nationwide network. 

About Exario Networks

Exario Networks is a leading provider of advanced IP services specializing in the design, implementation and management of next generation voice enabled wide area networks. The Company takes advantage of IP technology and voice and data convergence over a private ATM infrastructure to create unique and highly scaleable networking solutions for companies requiring the highest levels of network security and quality of service. The firm is headquartered in Parsippany, New Jersey and maintains a west coast sales office in Pleasanton, California. For additional information, please call 1-888-2-EXARIO or visit the company's website at http://www.exario.net. 

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 market share 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' Quarterly Report on Form 10-Q, dated May 14, 2001, 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.

GSX9000, PSX6000 and Open Services Architecture are trademarks of Sonus Networks. INtelligentIP 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.