Comcast, the nation's largest cable company, said today that it will change its controversial network management practices and work with file-sharing services to address complaints that it unfairly blocks certain peer-to-peer traffic. But consumer groups weren't buying it.

The Federal Communications Commission is currently investigating Comcast over charges that it stifles legal peer-to-peer traffic on its network. Consumer groups and network-neutrality advocates have been pushing the F.C.C. and Congress to forbid Comcast to discriminate against legal traffic on its network.

Today's announcement is a stunning turnaround for a company that until just months ago denied it engaged in any Web blocking at all. After the Associated Press caught Comcast blocking certain traffic, the company was forced to admit that it "delays" certain peer-to-peer traffic, but it defended the practice as "reasonable network management."

Comcast said that by the end of 2008, its network-management policy will be "protocol agnostic"—meaning it will not favor one type of traffic over another—and will instead focus on users who consume the most bandwidth.

"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," Comcast chief technology officer Tony Werner said in a statement.

Comcast will also expand its network capacity to better accommodate rapidly increasing bandwidth consumption, said John Schanz, a Comcast Cable executive vice president.

"We plan to more than double the upstream capacity of our residential internet service in several key markets by year end 2008," Schanz said.

Comcast also said it had agreed to work with file-sharing service BitTorrent in an effort to address the best way to manage peer-to-peer traffic, one of the most bandwidth-intensive activities on the Web.

"Recognizing that the Web is richer and more bandwidth-intensive than it has been historically, we are pleased that Comcast understands these changing traffic patterns and wants to collaborate with us to migrate to techniques that the internet community will find to be more transparent," said Eric Klinker, BitTorrent's chief technology officer.