Three high-tech communications companies will offer an ultrafast data pipeline and some of the needed network equipment as part of a $500 million contribution toward developing the next generation of the Internet.

The revolutionary network - so fast it will transmit the contents of the 30-volume Encyclopedia Brittanica in one second - will make possible new ways of using computers, from long-distance learning to allowing a specialist in another city to look at real-time images of a beating heart and make a diagnosis.Vice President Al Gore made the formal announcement at the White House Tuesday. The spring meeting of the project's organizers, the University Corporation for Advanced Internet Development, begins Wednesday in Washington.

Gore also announced a $50 million investment in Internet-related projects by the Defense Advanced Research Projects Agency, the central research and development organization for the Defense Department. The existing Internet - originally called ARPANET - grew from investments by the agency during the 1960s.

For the project, Qwest Communications International offered use of its high-speed, fiber-optic network, which runs from Los Angeles to New York. The administration put the market value of Qwest's offer at $500 million over three years. The other two companies, Cisco Systems and Northern Telecom, are offering network equipment, such as routers and switches.

The administration said the gesture allows the companies, in turn, to work with the top researchers in the field.

Administration officials said the new Internet will focus on better reliability for network-critical projects, such as telemedicine. The current Internet treats all chunks of data - whether it's an innocuous e-mail message or an image of an infant's failing heart - as the same priority as they travel over the worldwide network.

The new Internet also will be faster. In its earliest stages, organizers hope to connect at least 100 universities about 100 times faster than current connections allow and a smaller group of schools at speeds 1,000 times faster.

Researchers also are looking at the new types of software applications that would be possible under such a super-fast network, including improved weather forecasting.

President Clinton referred to the new Internet during his 1997 State of the Union address, when he pledged support for a "second generation of the Internet so that our leading universities and national laboratories can communicate in speeds 1,000 times faster than today."