Britain's Leading Cable Company, Telewest, Gets Wired With Portal; Portal Software Poised For Success as UK Embraces Broadband Over Cable.

Business Editors and High-Tech Writers

CUPERTINO, Calif.--(BUSINESS WIRE)--March 28, 2000

Portal Software, Inc. (NASDAQ: PRSF), a leading provider of business infrastructure software for Internet and next-generation communications services, today announced that Britain's Telewest Communications, a leading broadband cable communications service company, has selected Portal's Infranet(R) to propel its launch of high-speed broadband Internet services for its UK cable subscribers. Telewest will launch its high speed Internet service later this month, and is predicting explosive growth in the UK cable market.

The deal, announced on March 21 in London, follows a series of collaborative alliances with leading equipment vendors, systems integrators and other key technology companies that Portal announced on February 29. This included alliances with Cisco and Motorola in which Portal provides integrated solutions for advanced cable services. Portal's cable strategy is based on the development of product extensions that support a new class of value-added services over cable, including high-speed Internet access and voice over IP (VOIP).

The selection of Portal's customer management software signals a vote of confidence by Telewest that Portal's Infranet system will meet two of its key criteria: real-time flexible customer management capabilities and speed of implementation. Real-time capabilities during user authentication and authorization are essential to prevent fraud, a major concern with Internet service providers (ISPs) and cable operators.

"Cable operators worldwide are moving into the increasingly competitive and financially lucrative broadband access and services market," said John Little, founder and chief executive officer of Portal Software. "Our real-time software will enable them to quickly offer the potential of dramatically increasing their revenue per subscriber.

In recent weeks Portal has achieved some notable success in penetrating the global cable market. In addition to our alliances with Cisco and Motorola, we recently announced that Globocabo, Latin America's leading cable company, and Pacific Convergence Corporation, a leading provider of broadband Internet services in Asia, have both selected Portal to support their advanced cable service offerings."

"To take advantage of the high speed Internet service market we needed software that can give us flexible pricing, react in real time, be future-proof and also be compatible with our existing system," said David Ferguson, group director of Broadband Internet at Telewest Communications.

Portal Enables Cable Operators to Attack a Lucrative Market Opportunity

With the ability to offer bundled packages of advanced services that deliver choice and interactivity to the many current cable consumers, the next-generation cable market is positioned to drive the next big wave of Internet growth. In order to address this tremendous market opportunity, cable operators and service providers must either upgrade or build a cable infrastructure that can support this new multi-service IP-based business environment. Portal's Infranet provides them with a cost-effective solution to this problem.

Portal currently plans to develop product extensions for cable operators and service providers available mid-year 2000. Portal's planned cable enhancements will support emerging advanced cable services with a complete range of powerful rating and billing capabilities. With Portal's comprehensive real-time technology, cable operators can quickly bring new services to market unlocking new sources of revenue, improving customer satisfaction and reducing costs by managing services in real-time. Portal's cable solution addresses cable service companies' specific challenges including high subscriber growth, multi-service offerings, bundled pricing packages, real-time support for on-demand applications, usage-based pricing, virtual branding capabilities and augmenting existing basic cable billing systems.

About Telewest Communications

Telewest Communications is a leading broadband cable communication services company, providing digital and analogue cable television, telephone and Internet services to 1.6 million homes and delivering business communications solutions to more than 54,000 public and private sector organizations.

About Portal Software, Inc.

Portal Software, Inc., is building business infrastructure for the Internet. Based in Cupertino, Calif., Portal is the leading provider of customer management and billing software for Internet and emerging, next-generation communications services. The company's real-time solution enables service providers to manage customers, support services and collect money. Portal's customers include US WEST, Qwest Communications, Inktomi, Covad, Deutsche Telekom's T-Online, Telenor Mobil AS, Juno Online, France Telecom and Demon. Information about Portal and its products can be found at http://www.portal.com.

Note to Editors: Portal Software, Inc. All rights reserved. Infranet is a U.S. registered trademark, and Portal Software, the Portal logo, and Infranet are trademarks of Portal Software, Inc. All statements made in this press release are made only as of the date set forth at the beginning of this release. Portal undertakes no obligation to update the information in the event facts or circumstances subsequently change.