The man often called the father of the Internet told U.S. lawmakers Tuesday that the future of the Internet is at risk if Congress does not pass a law prohibiting broadband providers from discriminating against competing Web applications and computer devices.

Congress needs to keep large broadband carriers from favoring their own services and slowing down access to competitors and from charging some Web sites for faster speeds, said Vinton Cerf, co-designer of the TCP/IP (Transmission Control Protocol / Internet Protocol).

But representatives of the large telecom carriers and the cable television industry promised that they would not block or slow access to Web sites and applications.

"Our commitment to our customers, our commitment to you is this: We will not block, impair or degrade content, applications or service," said Walter McCormick, president and chief executive of the United States Telecom Association (USTA), representing large telecom carriers. "That is the plainest, most direct way I know to address the concerns that have been raised."

Echoing consumer group concerns that the newly deregulated telecom carriers will try to give their own services better speeds over broadband networks, Cerf asked the Senate Commerce, Science and Transportation Committee to adopt a ’Net neutrality law, requiring broadband providers to allow customers to go to any legal Web sites, attach any legal devices and run any legal applications on their networks. If large broadband providers are allowed to charge Web sites or Web-based application vendors extra for customer access, small innovative companies will get frozen out, he said.

"Nothing less than the future of the Internet is at stake in these discussions," said Cerf, now vice president and chief Internet evangelist at Google Inc. "We must preserve neutrality in the system in order to allow the new Googles of the world, the new Yahoos, the new Amazons to form. We risk losing the Internet as catalyst for consumer choice, for economic growth, for technological innovation and for global competitiveness."

While USTA and the National Cable and Telecommunications Association promised not to block or impair Web sites and services, some consumer groups have criticized proposals by AT&T Inc. and BellSouth Corp. to wall off high-speed broadband service for their own video services. Many consumer groups have also pointed to recent comments from AT&T and Verizon Communications Inc. executives indicating they want to charge sites like Google for delivering customers to them.

On Tuesday, The Washington Post quoted Verizon Vice President and Deputy General Counsel John Thorne as complaining that Web sites like Google are getting a "free lunch" by using telecom carriers’ networks. "The network builders are spending a fortune constructing and maintaining the networks that Google intends to ride on with nothing but cheap servers," Thorne was quoted as saying. "It is enjoying a free lunch that should, by any rational account, be the lunch of the facilities providers."