CHICAGO — Those amusing YouTube video clips that Internet users send to friends gobble up large chunks of bandwidth and may cause the Net to crash, some elements of the telecom industry warn.

It's an admonition many dismiss as political posturing intended to dissuade lawmakers from restricting the freedom of phone companies to manage Internet traffic as they wish.

But no one disagrees that the Web's capacity is being pushed to its limits.

"We don't see anything catastrophic near term, but over the next few years there's this fundamental wall we're heading toward," said Pieter Poll, chief technology officer at Qwest Communications International Inc., one of the operators of the Internet backbones, which are the big pipes at the network's center.

The problem, Poll said, is that traffic volumes are growing faster than computing power, meaning that engineers can no longer count on newer, faster computers to keep ahead of their capacity demands.

A recent report from Deloitte Consulting raised the possibility that 2007 would see Internet demand exceed capacity. Worldwide more users every day join the 1 billion people who now use the Internet. Popularity of bandwidth-hungry video makes far greater demands on the network than more basic applications like e-mail, Web browsing or even voice over the Internet.

"For some service providers," the Deloitte report said, "video-chat traffic already exceeds voice volumes, and given that a minute of video requires 10 times the bandwidth as voice, the threat to bandwidth becomes clear."

David Tansley, a London-based Deloitte partner, said that "so many business models assume Internet capacity to be ubiquitous and inexpensive that capacity isn't seen as a limiting factor in applications.

"Yet little thought is given to how infrastructure providers may be incented to keep investing."

While the network was famously overbuilt during enthusiasm of the 1990s' Internet bubble, much of that capacity is being used now or soon will be, Tansley said, and network operators are faced with making significant investment to expand capacity further to meet growing demands fueled largely by video applications.

"2007 may be the year of the tipping point where growth in capacity cannot cope with use," Tansley said.

The Deloitte report and comments earlier this month by a Google executive at a technology conference in Amsterdam about Web capacity problems have been cited as examples why telecom companies shouldn't face new regulations.

Walter McCormick Jr., chief of US Telecom, the trade group representing dominant phone companies, wrote to lawmakers arguing that the need to manage capacity would be impeded if so-called network neutrality legislation passes.

Backed by several consumer groups as well as large Internet enterprises such as Google, network neutrality legislation forbids phone companies from managing the network to favor one Internet user's content over another's. Network managers need flexibility in order to provide needed capacity as demand grows, McCormick contends.