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Company Delivers Class 5 Feature Set Through PSX6000 SoftSwitch and GSX9000 Open Services Switch; Provides Support for Range of Key Access Solutions and Protocols 

WESTFORD, Mass., June 6, 2000 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure products for the new public network, today outlined its strategy for moving access providers, such as ILECs and CLECs, away from Class 5 circuit-switched infrastructures to packet-based networks. The powerful combination of Sonus’ PSX6000 SoftSwitch and GSX9000 Open Services Switch will enable Sonus’ carrier customers to provide Class 5 features to their subscribers. Additionally, the Sonus solution also supports a range of packet-based access solutions based on integrated access devices (IADs), DSL, cable, wireless and residential and access gateways. 

"The core of the PSTN – the long distance network – was the first to undertake the migration to packet. Now access providers, who connect subscribers to the core network, are making this transition," said Hassan Ahmed, president and CEO, Sonus Networks. "Our strategy combines Class 5 functions and Class 4 capabilities in a single, comprehensive packet solution. This approach will enable carriers to maximize the functionality of their network while taking advantage of the well-understood benefits of a packet-based infrastructure."

These new capabilities bolster Sonus’ current product offerings for trunking infrastructure and Internet traffic offload applications, which are being deployed by major service providers, including Global Crossing, Williams Communications, Intermedia Communications, Z-Tel Technologies and Cybertel. In an announcement issued today, BroadBand Office, a leading global provider of communications, Internet and e-business solutions, announced that it is deploying Sonus’ products to provide facilities-based local and long distance voice services. (See today’s press release "BroadBand Office and Sonus Networks Partner to Build Nationwide, Next-Generation Packet Voice Network")

"Our core business is to enable customers within our network to simply plug into a wall jack and immediately have access to a comprehensive set of voice and data services," said Johnson Agogbua, vice president of engineering, BroadBand Office. "In building our new infrastructure, we wanted a packet-driven, next-generation switching platform that provides us with the scalability, flexibility and manageability that our customers would demand. Sonus fits the bill."

Sonus SoftSwitch Supports Basic and Enhanced Voice Services

Sonus is providing support for critical Class 5, or access, features to legacy telephony devices such as PBXs and key systems. Some examples of these features are directory assistance, emergency 911 service, call waiting, call forwarding, call hold, 3-way calling and others. By deploying the Sonus solution, carriers also have the ability to customize and extend the features available, as well as seamlessly integrate any number of third-party premises equipment and enhanced service applications. Through its Open Services Partner AllianceTM (OSPA), Sonus works with dozens of telecommunications companies developing innovative new equipment and services for the carrier market.

Sonus is employing a multi-faceted strategy for helping carriers migrate from traditional Class 5 infrastructures to new packet-based networks. The industry has seen significant growth in the deployment of packet-based access approaches such as xDSL, cable and wireless. In this scenario, access devices such as cable modems, DSL modems and IADs convert audio streams coming from subscribers’ telephones to packets. This new telephony model also features an emerging class of native IP devices including IP phones and wireless phones. The Sonus PSX6000 SoftSwitch controls these packet access devices using standard protocols such as MGCP, SIP, H.323 and Megacop/H.248, and routes calls between access devices or to the PSTN through the GSX9000 Open Services Switch.

The PSX6000 handles all call routing and signaling, and provides basic services formerly provided by the traditional Class 5 switch. It also interfaces with third-party CPE devices, feature servers and application servers to deliver enhanced services such as unified communications, single number service, Internet click-to-talk and more. 

"Sonus seems to be on the right track in delivering a comprehensive set of voice services with the strategy they’ve outlined today," said Michael Rouleau, senior vice president of marketing, Time Warner Telecom. "The Sonus solution would give carriers the ability to offer a full complement of local and long distance services, using a single, compact and cost-effective platform. That’s a very powerful proposition."

Sonus will begin delivering this new functionality through the PSX6000 SoftSwitch and GSX9000 Open Services Switch over the next quarter.

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 ArchitectureTM (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 marketshare 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. 

This press release may contain forward-looking statements relating to future events or future financial performance that involve risks and uncertainties. These statements are made pursuant to the safe harbor provisions of Section 21E of the Securities Exchange Act of 1934. These statements are only predictions and actual results could differ materially from those anticipated in these statements based upon a number of factors including those risk factors identified in the Company's Prospectus dated May 24, 2000.

PSX6000, GSX9000, Open Services Partner Alliance 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.