For more information, please contact:

Companies Help Sonus Offer Carrier Customers End-to-End Voice Solutions for Next-Generation Networks

WESTFORD, Mass., August 1, 2001 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced that six companies have joined Sonus' Open Services Partner Alliance^(TM) (OSPA), further strengthening one of the premier partner initiatives in the telecommunications industry.

The OSPA consists of nearly 150 partners, which collectively offer a wide variety of enhanced services, network infrastructure solutions, service programs and next-generation technologies. Sonus partners with industry members that offer innovative solutions that complement Sonus' market-leading packet voice platform. 

Joining the program are ECtel Inc. of Ft. Lauderdale, Fla.; EngineX Networks of Alameda, Calif.; maxxio technologies AG of Munich, Germany; NetCentrex of San Jose, Calif., and Paris, France; Sitara Networks of Waltham, Mass.; and Telera Inc. of Campbell, Calif.

"We at Sonus pride ourselves on working with our customers to provide complete end-to-end solutions for their next-generation voice platforms," said Terri Griffin, vice president of marketing at Sonus Networks. "The OSPA gives us a mechanism to promote products and services that can help carriers add value to their networks today. We welcome each of these new members, and we look forward to working with them."

Companies joining the Sonus OSPA today offer a wide variety of enhanced services, network infrastructure solutions and OSS solutions to carriers and service providers:

• ECtel is a leading developer and provider of monitoring solutions for converged telecommunications networks. ECtel (Nasdaq: ECTX) develops and markets revenue assurance applications that enable telecommunications service providers to: monitor and assure high quality of service over telecom networks; detect and prevent fraud over wireline and wireless telephony networks; and bill for inter-carrier traffic and services. ECtel also provides governmental agencies with comprehensive solutions for their telecommunications monitoring needs. (www.ectel.com) 
• EngineX Networks is a professional services firm pioneering the design and implementation of advanced optical packet and wireless IP technologies in next-generation public networks and the support systems required to operate and manage them. The EngineX vendor-neutral approach guarantees optimal technical alternatives to meet today's needs while providing a clear migration path for the future. Headquartered in the Telecom Corridor of Richardson, Texas, the company maintains sales and support offices globally. (www.exn.com) 
• maxxio technologies is a network infrastructure provider that sells Linux-based, next-generation integrated access devices (IADs) to competitive and incumbent local exchange carriers. The maxxio "softIAD" product gives carriers the ability to integrate data and voice services in a standards-based, open architecture. The company is focusing its sales efforts in Europe. (www.maxxio.com) 
• NetCentrex offers service providers and enterprises a suite of next-generation networking products and network-based applications for VoIP, PSTN and mobile networks. The products enable service providers to build converged networks and to offer network-based multi-media services for the customer relationship management, consumer and enterprise markets. NetCentrex products include a multi-protocol softswitch and media server platform, an application development and execution platform, and applications for multi-media call centers, VoIP VPNs, IP Centrex services and residential telephony. (www.netcentrex.net) 
• Sitara Networks delivers QoS (Quality of Service) tools that network managers use to monitor traffic patterns, optimize WAN bandwidth utilization, improve response times for business critical applications and validate service level agreements (SLAs). Using Sitara's QoSDirector central policy manager product, administrators in service provider and enterprise environments can set and distribute precise policies for all traffic types across multiple locations. This ensures that mission-critical traffic and high priority users get the bandwidth they need, while, at the same time, fairly allocating remaining bandwidth to other locations, users and applications. (www.sitaranetworks.com) 
• Telera provides a platform that the world's leading service providers use to deliver the Voice Web to businesses of all sizes – from the Fortune 500 to small- and mid-sized enterprises. Telera's award-winning Voice Web Application PlatformTM is built using standard Internet technologies, allowing business applications to be delivered via any Web server. These applications give telephone users functionality typically associated with the Internet - such as Web content, e-commerce transactions, and highly personalized self-service – and, as a result, provide the backbone for highly advanced customer care systems. (www.telera.com)

About Sonus' OSPA

Founded on the combination of Sonus' Open Services Partner Alliance (OSPA) Program and the INIP PoweredSM Partner Program from the acquisition of telecom technologies, inc., the OSPA has gained significant industry momentum, with membership of more than 140 leading independent vendors. The OSPA provides a framework that offers service providers end-to-end packet-based network solutions using best-of-breed technologies and applications. The goal of the OSPA is to empower standards-based interoperability between applications, hardware vendors, and the Sonus product suite. An integral part of the Sonus OSPA, the Interoperability Laboratory in Richardson, Texas, is the first in the industry where product interoperability is verified, trial testing is performed, and complete solutions are ultimately produced. Additional information on the OSPA is available at http://ospa.sonusnet.com.

About Sonus Networks

Sonus Networks 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.

Open Services Partner Alliance and Open Services Architecture are trademarks of Sonus Networks. INtelligentIP is a registered trademark of Sonus Networks. INIP Powered is a service mark of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.