Network to support enhanced voice services, benefiting mobile, corporate and enterprise customers

LONDON, ENGLAND and WESTFORD, Mass., November 1, 2002 - Interoute, owner and operator of Europe's most advanced and densely connected fibre-optic network, and Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced that Interoute has chosen Sonus to build out its next-generation voice network. The Sonus-based network will allow Interoute to provide enterprises and mobile service providers with enhanced voice services.

Commenting on the announcement, James Kinsella, Executive Chairman of Interoute said: "The deployment will enable Interoute to provide IP-based services that utilise next generation voice technologies to deliver demonstrable cost-savings and flexibility to our customers.

It further strengthens Interoute's ability to serve mobile, corporate and enterprise customers and enhances its position as a provider of traditional and converged services to enterprise and mobile operators."

Under the terms of the contract, the companies are collaborating to build a pan-European next-generation network that supports a variety of enterprise communications services. As the foundation of the network implementation, Interoute has begun deploying a complement of Sonus' industry-leading packet voice solutions, including the GSX9000(TM) Open Services Switch, the Insignus(TM) Softswitch and the Sonus Insight(TM) Management System.

"We are pleased to be working with Interoute to create a scalable, high-performance next-generation packet voice network to support their business initiatives," said Hassan Ahmed, president and CEO, Sonus Networks. "By deploying our packet voice infrastructure, Interoute can expand their product portfolio, providing new, innovative enhanced service offerings to their customers."

About Interoute

Interoute - owner and operator of Europe's most advanced and densely-connected voice and data network - delivers intelligent, customer-controlled network services to a diverse range of businesses including mobile operators, service providers and enterprise customers. Unencumbered by debt, and with established operations throughout mainland Europe and North America, Interoute also owns and operates dense city networks in Amsterdam, Frankfurt, London, Madrid, Milan, Paris, Rome, Zurich and Vienna. For more information please visit www.interoute.com.

No representations or warranties are given as to the achievement or reasonableness of any future projections, management estimates, prospects or returns relating to Interoute which may be contained in the statements above.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of packet voice infrastructure products for the new public network. With its Open Services Architecture(TM) (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking, residential access and Centrex, tandem switching, and IP voice termination, as well as enhanced services. Sonus' award-winning 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 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 August 14, 2002 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. These risk factors include, among others, the adverse effect of recent developments in the telecommunications industry, the weakened financial position of many emerging service providers, Sonus' ability to grow its customer base, dependence on new product offerings, market acceptance of its products, rapid technological and market change and manufacturing and sourcing risks.

Open Services Partner Alliance is a service mark of Sonus Networks and Insignus, GSX9000 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.