Leading European Provider Of VoIP Services To Deploy Additional Sonus Equipment To Meet Customer Demand

SWINDON, UK, 21st October, 2004 - Sonus Networks (Nasdaq: SONS), a leading provider of voice over IP (VoIP) infrastructure solutions, today announced that Interoute, owner and operator of one of Europe’s most advanced telecommunications networks, is deploying additional Sonus equipment to meet growing demand for its successful Virtual Voice Network (VVN).

Interoute’s VVN service is one of the fastest growing parts of the company’s business and enables telecommunication operators, ISPs and service providers to enter the voice market in a cost-effective way by accessing a ready-made voice network.

Since Interoute first partnered with Sonus to launch its VVN in May, Interoute has witnessed strong demand for its service, and the company expects to carry more than 100 million minutes of voice traffic per month by the end of 2004.

Interoute is implementing a full set of Sonus solutions, including the GSX9000TM Open Services Switch, the InsignusTM Softswitch and the Sonus InsightTM Management System, to enhance the scalability of their existing network with high-density STM-1 interfaces, and expand its geographical reach, supporting new Points of Presence (PoPs).

"The VVN concept is proving popular with a range of companies, from incumbent operators through to ISPs and service providers, because it helps them to meet the needs of their end customers," commented Gareth Williams, president global markets, Interoute. "IDC predicts that 45 percent of European companies will have integrated their voice and data traffic by the end of 2005. With Sonus' softswitch technology we can enable service providers to support these converged services without the capital and operational expenditure required to create and manage their own infrastructure."

Interoute’s VVN delivers a full suite of partitioning, telehousing, bandwidth and professional services across all of Interoute’s European PoPs. Moreover, the flexibility and versatility of Sonus’ voice infrastructure solutions allow Interoute to deliver tailored services to address the specific business requirements of its customers.

“Progressive carriers such as Interoute are proving that next-generation networks offer new business models and enable increased profitability,” said Steve Edwards, chief marketing officer and general manager, EMEA, Sonus Networks. “Implementing our flexible softswitch architecture enables infrastructure owners to deliver revenue-generating voice services, either for themselves or for third parties."

About Interoute

Interoute is Europe’s fastest growing telecoms provider and owner operator of Europe’s most advanced and densely connected voice and data network. It delivers intelligent, customer-controlled network services to a diverse range of businesses including carriers, mobile operators, service providers, enterprise customers and government departments. Unencumbered by debt, and with established operations throughout mainland Europe and North America, Interoute also owns and operates dense city networks throughout Europe’s major business centers. http://www.interoute.com.

For further information about Interoute, please contact:
Kasia Ciszak
Text 100
Email: kasia.ciszak@text100.co.uk
Telephone: 0208 996 4137

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 ArchitectureTM (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 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/A dated July 28, 2004 and filed with the SEC, and the “Cautionary Statements” section of Sonus’ Quarterly Report on Form 10-Q, dated August 20, 2004 and filed with the SEC, which identify important risk factors that could cause actual results to differ from those contained in the forward-looking statements. 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 and Insignus are trademarks of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.