United States cable and internet service provider Comcast Corp., under investigation for hampering online file-sharing by its subscribers, announced Thursday an about-face in its stance and said it would treat all types of Internet traffic equally.

Since user reports of interference with file-sharing traffic were confirmed by an Associated Press investigation in October, Comcast has been vigorously defending its practices, most recently at a hearing of the Federal Communications Commission in February.

Consumer and "net neutrality" advocates have been vigorous in their attacks on the company, saying that by secretly blocking some connections between file-sharing computers, Comcast made itself a judge and gatekeeper for the internet. They also accused Comcast of stifling delivery of internet video, an emerging competitor to the cable company's core business.

Comcast has said that its practices were necessary to keep file-sharing traffic from overwhelming local cable lines, where neighbours share capacity with one another.

On Thursday, Comcast said that by the end of the year, it will move to a system that manages capacity without favouring one type of traffic over another.

"This means that we will have to rapidly reconfigure our network management systems, but the outcome will be a traffic management technique that is more appropriate for today's emerging internet trends," Tony Werner, Comcast's chief technology officer, said in a statement.

File-sharing becoming means of legal distribution

The company initially veiled its traffic-management system in secrecy, saying openness would allow users to circumvent it. But on Thursday, Werner said the company would "publish" the new technique and take into account feedback from the Internet community.

Comcast has been hampering the BitTorrent file-sharing protocol, which together with the eDonkey protocol, accounts for about a third of all internet traffic, according to figures from Arbor Networks. The vast majority of that is illegal sharing of copyright-protected files, but file-sharing is also emerging as a low-cost way of distributing legal content — in particular, video.

Peer-to-peer file-sharing "has matured as an enabler for legal content distribution," Werner said. "So we need to have an architecture that can support it with techniques that work over all networks."

Comcast now says it is in talks with BitTorrent Inc., the company founded by the creator of the protocol, to come up with better ways to transport large files over the internet. The companies said they want to work out these issues privately, without the need for government intervention.

FCC commissioners have indicated that they take the issue seriously, and commission chairman Kevin Martin has voiced objections to secret traffic management.

For its part, BitTorrent acknowledged that service providers have to manage their networks somehow, especially during peak times.

Other U.S. companies exploring caps

"While we think there were other management techniques that could have been deployed, we understand why Comcast and other ISPs adopted the approach that they did initially," Eric Klinker, BitTorrent's chief technology officer, said in a statement.

Verizon Communications Inc. two weeks ago announced the results of a collaboration project with Pando Networks, another file-sharing company. By sharing information with Pando, Verizon was able to speed up file-sharing downloads for its subscribers while reducing the strain on its own network.

AT&T Inc., the largest U.S. internet service provider, has been looking at a similar collaboration. However, phone companies are in a better position than cable companies to deal with file-sharing traffic, since neighbours don't share capacity on phone lines.

Time Warner Cable is experimenting with another way of managing traffic, placing explicit caps on the monthly downloads for new customers in Beaumont, Texas. Subscribers who go over their allotment will pay extra, much like a cell-phone subscriber who uses too many minutes in a month.