The tests come as the Federal Communications Commission wraps up an investigation on complaints that Comcast blocked certain users from sharing video, music and other files. The complaints fueled a larger debate, with hearings in Congress and by the FCC, on how much control Internet service providers should have over the flow of data.  "The cable companies see a hammer hovering above their heads and are scrambling to find ways to reduce the appearance of wrongdoing," said Ben Scott, head of policy for the public interest group Free Press, which advocates for better oversight of cable operators. He called the plans "Band-Aids" on the bigger problem of network capacity, which he said can be solved only by larger investments in the cable companies' networks.  Comcast said that on Friday it would begin tests in Chambersburg, Pa., and Warrenton, Va., that would delay traffic for the heaviest users of Internet data without targeting specific software applications. Public interest groups complained in November that Comcast targeted users of BitTorrent, a file-sharing application, by blocking or delaying video and other files exchanged with the technology. Free Press said the practice discriminated against certain content and impeded users from having full access to the Web.  FCC Chairman Kevin J. Martin has said the commission would announce the results of its review of the complaints by the end of June.  Analysts said the test would not differ significantly from Comcast's current network-management practices. The new approach would, however, target a broader range of heavy bandwidth users instead of delaying all traffic using BitTorrent. Roger Entner, a senior vice president at Nielsen IAG, said about 5 to 10 percent of peer-to-peer users -- those who directly exchange files with other users -- gobble up about 50 percent of all Internet bandwidth.  "This is the politically correct version of doing what Comcast had been doing before, though it takes the occasional [peer-to-peer] user off the hook," Entner said.  Sena Fitzmaurice, a spokeswoman for Comcast, acknowledged the earlier criticism but said, "This says we won't be looking at what type of traffic that there is, even though we still need to manage the network."  Time Warner Cable is trying a different approach with a test that will charge customers more for larger volumes of data and faster Internet access. The metered-billing test, which the company compared to cellphone billing structures that charge extra for those who go over their minutes, will begin tomorrow with new customers in Beaumont, Tex. The company said its approach allows customers to choose plans that fit their needs.  "Instead of raising prices across the board, consumers who are excessive users would pay," said Alex Dudley, a spokesman for Time Warner Cable. "It is clearly the fairest way to fund the investment that is going to be required to support that use."  Analysts warned that customers have become accustomed to flat fees for Internet and television service.  "Flat rate and unlimited service is an endgame move. When you go to that kind of rate structure, you can't go back," Entner said.
Cable service operators Comcast and Time Warner Cable said yesterday that they would begin testing new approaches that would slow Internet access for heavy users and charge more to those who want additional speed.