Comcast Cable and Cox Communications have both been found to employ technologies that block or slow customers' access to the BitTorrent file-sharing engine, according to a new report [1].

Researchers at the Max Planck Institute for Software Systems in Germany conducted their study through measuring the traffic of 8,175 Internet users across the world.

The researchers detected conclusive evidence of "traffic shaping" or blocking from only three Internet service providers -- Comcast and Cox in the United States, and StarHub in Singapore. The researchers said 599 users were blocked in the United States, 573 of them on Comcast or Cox networks.

Although Comcast originally defended its content blocking practices as "reasonable network management" [1] that was concentrated on peak hours of Internet use, the Institute's report indicated that both Comcast and Cox blocked access to BitTorrent at all times of the day.

"The percentage of blocked connections remains high at all times of the day," the report authors said. "Our data suggests that the BitTorrent blocking is independent of the time of the day."

Supporters of "net neutrality," the principle that all Internet content should be accessed equally, pointed to the discovery as further evidence that cable and other Internet providers cannot be trusted to police their networks without infringing on users' rights. "Consumers have no reason left to trust their cable company," said [2] Ben Scott, policy director of Free Press. "This independent study confirms that Comcast is still blocking its customers from using popular applications -- despite the FCC's investigation [2] and widespread public outrage."

Comcast's content blocking, [2] first confirmed in October 2007, also led to customer lawsuits [2], and several hearings into proper network management conducted by the FCC. Comcast's image was further tarnished by its paying people to fill seats [2] at the first hearing in Cambridge, Massachusetts.

Cox released a brief statement [3] to the Associated Press claiming that "[t]o ensure the best possible online experience for our customers, Cox actively manages network traffic through a variety of methods including traffic prioritization and protocol filtering."

The renewed push for net neutrality protection against content blocking has led to the introduction of several pieces of legislation in Congress.

One bill, the "Internet Freedom Preservation Act" [3] co-sponsored by Rep. Ed Markey (D-MA), would amend the Communications Act of 1934 to include the principles of open access to the Internet as codified law. The "Internet Freedom and Nondiscrimination Act," [3] introduced by House Judiciary Chairman John Conyers (D-MI), would use antitrust regulations to prevent price discrimination through forcing different customers to pay more for higher bandwith usage.