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Next-Generation Softswitch Architecture Sets New Standard for Industry; Insignus Softswitch Supports Full Breadth of Class 4 and Class 5 Carrier Applications

WESTFORD, Mass., November 19, 2001 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, is advancing the state of softswitching with its distributed softswitch architecture, the Insignus^(TM) Softswitch. The Insignus Softswitch expands upon the industry-leading softswitching technologies that Sonus has been deploying for years, and provides new modules that deliver residential Class 5 and enterprise Centrex services, full H.323 gatekeeper and gateway functionality, as well as comprehensive SIP (Session Initiation Protocol) support. 

The Insignus Softswitch builds on the field-proven capabilities of Sonus' softswitch solutions to deliver the highest levels of flexibility, scalability, performance and redundancy. With its unique modular software architecture, the Insignus Softswitch provides the rich functionality necessary to support a full range of carrier applications including trunking, Internet call diversion, tandem replacement and access.

"As the new public network continues to evolve, carriers seek a comprehensive softswitch solution that will accommodate their requirements today, and will grow forward with them in the future," said Terri Griffin, vice president, marketing, Sonus Networks. "With the Insignus Softswitch, we are raising the bar for softswitching. We have leveraged the considerable experience we have gained through our deployment in major carrier networks to develop a highly robust solution that flexibly supports multiple carrier applications in a single platform."

Sonus' Insignus platform separates softswitch functionality into a set of modular software elements, which can be deployed in a variety of configurations to address carriers' individual requirements. These elements include:

• The ASX Access Server is a new module that supports a variety of access gateways to provide line-side endpoint control. Additionally, the ASX provides a rich set of Class 5 features for residential and Centrex applications, as well as regulatory features such as emergency services and CALEA;  
• The PSX Policy Server provides the service selection, routing and call handling instructions for other softswitch elements;  
• The GSX-GC Gateway Controller tsprovides call control and signaling for Sonus' award-winning GSX9000^(TM) Open Services Switch;  
• The new TSX Gateway Controller controls third-party trunking gateways using industry-standard protocols such as MGCP; and  
• The SGX SS7 Gateway provides integrated SS7/C7 signaling support for connectivity to existing circuit-switched networks.

Sonus also delivers full support for the SIP and H.323 protocols in the Insignus Softswitch. Sonus offers complete H.323 gatekeeper functionality on the Insignus platform and also delivers H.323 gateway capabilities in the GSX9000 Open Services Switch, allowing the Sonus systems to seamlessly interconnect to the world's legacy packet systems. The Insignus Softswitch also provides comprehensive SIP capabilities, which enables Sonus to integrate with enhanced services platforms and Class 5 feature servers. 

The various Insignus Softswitch components may be deployed in either a distributed or centralized configuration to meet a wide range of network requirements. For instance, a smaller carrier may deploy all of the Insignus Softswitch modules within a single point of presence (PoP) to manage its entire network, whereas a global service provider may locate a number of the Insignus resources on a regional basis. Additionally, some carriers not requiring all softswitch modules may choose only the components that apply to their business model, thus realizing even greater cost efficiencies.

Regardless of the configuration in which the Insignus Softswitch is deployed, carriers are assured that they will be able to support full Class 4 and Class 5 applications, all within a single softswitch platform. The Insignus Softswitch extends from the core to the edge of the network, enabling a diverse range of applications such as long distance and international, business PBX access, tandem switching, residential access and Centrex, IP voice termination and direct voice over broadband, as well as enhanced services. 

"Service providers worldwide are committed to packet voice infrastructures, and Sonus Networks has been at the forefront of delivering products to move carriers forward with this commitment," said Christin Flynn, director, The Yankee Group. "The modular Insignus Softswitch platform gives service providers a wide choice of features and functionality to meet the unique requirements of each individual network. Sonus is well positioned to be the trusted partner of service providers for their new voice infrastructure."

The Insignus Softswitch is an integral component of Sonus' Open Services Architecture^(TM) (OSA), an open telephony framework that provides end-to-end solutions enabling carriers to rapidly and easily deliver revenue-generating services. Other components of the OSA are the GSX9000 Open Services Switch, the Sonus Insight^(TM) Management System and the Open Services Partner AllianceSM (OSPA). Sonus' industry-leading Open Service Architecture has been deployed in service provider networks worldwide for more than two years, and currently drives more than 1 billion minutes of production traffic across these networks per month.

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 (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 November 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, integration risks relative to its acquisition of telecom technologies, rapid technological and market change and manufacturing and sourcing risks.

Insignus, GSX9000, Open Services Architecture and Sonus Insight are trademarks of Sonus Networks. Open Services Partner Alliance is a service mark of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.