Genuity Signs on as Lead Customer of the Application

DALLAS, Feb. 13, 2001 -- Allegiance Telecom, Inc. (NASDAQ: ALGX), a facilities-based integrated communications provider (ICP), today announced that it has launched a national carrier class dial-IP platform utilizing the efficiencies of softswitch technology. This new platform is able to segregate data calls from the voice switched network, increasing the reliability of data communications. As data traffic is separated, capacity on Allegiance's voice network is expanded. The cost of providing data calling services such as dial-up Internet access and corporate virtual private networks (VPNs) will be reduced via packet switching as compared with traditional circuit switched provisioning.

In connection with this launch, Allegiance Telecom announced that Genuity Inc. (NASDAQ: GENU), one of the largest Internet infrastructure providers in the world, has signed on as the lead customer of the new service platform. Allegiance will provide highly reliable, fiber-based carrier class service to Genuity, a leading provider of services to enterprises and leading ISPs. Genuity chose to work with Allegiance Telecom, a national provider, because it has extensive experience at the "edge of the network" (the part of the network that touches the customer). Allegiance Telecom is currently providing services in 27 U.S. markets, with nine more expected to be operational by the end of 2001. Allegiance is one of the few ICPs with a robust presence at the edge of the network and is also one of the few companies using both traditional switching (circuit) infrastructure and state-of-the-art softswitching technology.

As part of this development, Allegiance and Genuity have subjected the infrastructure to a rigorous Beta testing period to demonstrate the performance of the platform under a live Internet traffic load. With the Beta test proving successful, full-scale Genuity traffic on the Allegiance network began when production (as defined in the agreement) was achieved in the fourth quarter of 2000.

"Our softswitch technology is the next giant step in the evolution of Allegiance’s customer-oriented network infrastructure," said Royce J. Holland, chairman and CEO of Allegiance Telecom. "This is an important bridge between our circuit and packet switch platforms, allowing Allegiance Telecom to efficiently provide an integrated package of communications services to small and medium-sized businesses and to larger Internet infrastructure companies such as Genuity."

"Genuity chose to work with Allegiance Telecom because of parallel economies of scale between our two networks," said Jeff Feinberg, Genuity's vice president for remote access implementation. "Similar geographic market coverage, bolstered by fiber route diversity, made Allegiance a good choice for meeting Genuity's growing traffic demands and our high quality standards."

About Allegiance Telecom
Allegiance Telecom is a facilities-based integrated communications provider headquartered in Dallas, Texas. Allegiance offers businesses a complete package of telecommunications services, including local, long distance, international calling, high-speed data transmission and Internet services. Allegiance is targeting a total of 36 major metropolitan areas in the U.S. with its "one-stop shopping" approach and is currently operational in 27 markets, including: Atlanta, Baltimore, Boston, Chicago, Cleveland, Dallas, Denver, Detroit, Fort Worth, Houston, Long Island, Los Angeles, Miami, Minneapolis/St. Paul, New York, Northern New Jersey, Oakland, Orange County, Philadelphia, Phoenix, St. Louis, San Diego, San Francisco, San Jose, Seattle, Tampa and Washington, D.C. Allegiance Telecom’s common stock istraded on the Nasdaq National Market under the symbol ALGX. The company's Web address is: www.allegiancetele.com.

About Genuity
Genuity is a leading Internet infrastructure services provider and the only company in the industry to offer an eBusiness Network Platform. Genuity's Black Rocket combines its Tier 1 network with its full portfolio of managed Internet services, including dedicated, remote and broadband access, Web hosting and Internet security, to create a platform for creating scalable and repeatable managed eBusiness solutions. With annual revenues of more than $1billion, Genuity (NASDAQ: GENU) is a global company with offices and partnerships throughout the U.S., Europe, Asia and Latin America. Additional information about Genuity can be found at www.genuity.com.