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Deployment of Sonus' GSX9000™ Open Services Switch Will Enable Williams to Offer Innovative, Enhanced Voice Services; Order with $100 Million Potential is Major Win for Emerging Packet Telephony Leader

TULSA, Okla. and WESTFORD, Mass., Dec. 13, 1999 - Williams Communications (NYSE:WCG) has selected Sonus Networks' carrier-class packet telephony solution to augment Williams' next-generation voice-over-packet services, the companies announced today. The contract is valued at $20 million for the first year and could expand to more than $100 million over a three-year period. 

With more than 33,000 route miles connecting 125 cities and support for 800,000 voice ports planned by the end of 2000, the fully integrated, ATM-based architecture of the Williams Multi-Service Broadband Network^TM supports all Williams Communications carrier services, including voice, data, Internet and video. By deploying Sonus' Open Services Architecture^TM (OSA) and award-winning GSX9000 Open Services Switch within its nationwide fiber-optic network, Williams will complement its success in wholesale provisioning of bandwidth with a range of enhanced voice services. These innovative new services could include unified communications, call centers and Internet offload, among others. Additionally, the voice-over-packet network will have the capability to support traditional voice services such as 1+ dialing, 800 services, credit card calling and more, which are critical to Williams' current customer base of competitive local exchange carriers, switchless resellers, interexchange carriers and Internet service providers. 

Williams required a solution that has been designed to carrier standards, delivering toll-quality voice, system redundancy and the capacity to handle extremely large call volumes. Additionally, the carrier was seeking a solution that would enable it to integrate with, and gradually migrate from, its existing circuit-switched network architecture to a packet-based network that will deliver integrated voice and data services. 

"We conducted a thorough investigation of competitive solutions and selected Sonus' GSX9000 Open Services Switch as the cornerstone for our new next-generation voice network," said Matthew Bross, senior vice president and chief technology officer for Williams Communications. "The GSX9000 is the only solution that met our requirements for scalability and reliability, but more importantly it is unique in its ability to deliver operational savings and enable new revenue streams through services creation." 

"Williams has a rich history of technology innovation, having pioneered one of the nation's largest fiber-optic networks in the 1980s, and its strategic partnership with Sonus represents the latest step in this innovation," commented Tom Jenkins, senior consultant, TeleChoice. "Together, Williams and Sonus are developing one of the industry's first true next-generation voice networks, one that positions Williams to build its leadership in today's competitive carrier market, and sets up Sonus as a leader in the delivery of high-end voice-over-packet solutions." 

Williams' next-generation voice network will carry voice over packet and will be based on an asynchronous transfer mode (ATM) infrastructure. Sonus recently introduced a full range of media-independent, broadband solutions that enable service providers to recognize the considerable benefits of carrier-scale packet telephony, regardless of the underlying transport infrastructure. These innovative solutions include support for VoIP over ATM, voice telephony over ATM (VToA) and packet over SONET (POS), all of which take advantage of high-speed, optical infrastructures, such as the Williams network. 

"We're extremely excited that Williams Communications has selected the GSX9000 Open Services Switch as the platform for delivering comprehensive packet telephony capabilities to their customers," said Hassan Ahmed, Sonus' president and CEO. "Williams is recognized as a technology innovator and pioneer in the wholesale carrier services market, and we look forward to partnering with them to extend that leadership position." 

Beginning in December, Williams will deploy Sonus GSX9000 switches in three cities, and plans to rapidly deploy the new technology throughout its network. Previously, cost and physical considerations have made this level of expansion infeasible with circuit-switched technologies. Sonus' packet telephony systems are less costly to acquire, maintain and provision than circuit switches, and offer a high-density, compact footprint, enabling Williams to conserve limited and expensive Central Office space. 

"Because we can rapidly deploy the Sonus solution, we can manage our capital expenditure more efficiently - a key factor in our decision," Bross added. "Also important is the ability of the Sonus equipment to interoperate with the current equipment in the network, allowing a graceful migration to a next-generation voice architecture." 

About Williams Communications Group, Inc. (NYSE:WCG)

Williams Communications Group, through its subsidiaries, operates North America's only exclusively carrier-focused fiber-optic network and is the largest independent source of end-to-end integrated business communications solutions - data, voice or video. Based in Tulsa, Okla., Williams Communications has 9,000 employees primarily in North America, with offices in Europe and Asia and investments in South America and Australia. Approximately 85 percent of WCG stock is held by Williams (NYSE:WMB) which, in 1985, became the first energy company to harness its core competency as a builder of networks to enable competition in the communications industry.

Additional information is available at www.williams.com and www.williamscommunications.com. 

About Sonus Networks

Sonus Networks, Inc. is delivering a new class of carrier solutions that enable the movement of telephony to converged packet networks and the development of a new generation of innovative voice and data services. The award-winning Sonus Packet Telephony suite and Open Services Architecture^TM (OSA) cut the time-to-market for competitive new service products, allowing carriers and third-party developers to sustain and 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 solutions at companies such as Cisco Systems (Nasdaq: CSCO), Lucent Technologies (Nasdaq: LU), and Nortel Networks (NYSE: NT). Sonus, founded in 1997, is headquartered in Westford, Massachusetts and is privately held. Additional information is available at http://www.sonusnet.com. 

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. 

Portions of this document may constitute "forward-looking statements" as defined by federal law. Although the company believes any such statements are based on reasonable assumptions, there is no assurance that actual outcomes will not be materially different. Any such statements are made in reliance on the "safe harbor" protections provided under the Private Securities Reform Act of 1995. Additional information about issues that could lead to material changes in performance is contained in the company's annual reports filed with the Securities and Exchange Commission. This news release is not an offer to sell, nor the solicitation of an offer to buy, any securities. Any offer will be made only by means of a prospectus registered with the Securities and Exchange Commission.