The FCC’s August 1 “Data Discrimination” ruling against Comcast Corp. came under fire Thursday, after the Philadelphia-based nationwide ISP filed appeals to a U.S. District Court.

In its suit, Comcast accuses the FCC of overstepping its authority when it issued a formal cease-and-desist order against the company’s policy of interfering with subscribers’ BitTorrent traffic last month.

Comcast characterizes its policy – since nicknamed “data discrimination” by observers – as necessary in order to protect its infrastructure from being overwhelmed with traffic.

When it was discovered in October 2007, Comcast’s “data discrimination” policy targeted a number of P2P protocols – most notably BitTorrent – and actively inserted fake disconnect requests with forged return addresses.

While the suit recognizes the FCC’s authority in governing ISPs’ actions, it says that it has not enacted any “enforceable rules or standards” over the way internet providers manage their networks.

FCC chairman Kevin Martin said he was “disappointed” with the appeal, noting that there are still a number of unanswered questions regarding how the company manages its network.

“The commission needs to understand the answers,” he said. “Perhaps more importantly, Comcast's subscribers deserve to know the answers.”

In a statement justifying his August 1 ruling, Martin characterized Comcast’s policy as akin to “opening your mail, decided they didn’t want to bother delivering it, and hiding that fact by sending it back to you stamped ‘address unknown – return to sender’.” The ruling enjoined Comcast to cease the practice – something it already committed to doing on its own, earlier this year – and describe the exact nature of the techniques it uses to manage traffic on its network.

In its response to the August 1 ruling, Comcast accused the FCC of being “deeply divided” in its decision, and disagrees with Comcast’s contentions that its network management practices were “reasonable”.

The company’s policy shift, from “data discrimination” to its just-announced 250 GB usage cap, is seen as a direct response to continuing FCC pressure. As part of this new initiative, which it dubbed “fair share,” Comcast will actively and temporarily throttle service for customers hogging the network.

Comcast is the second-largest ISP in the country, maintaining a 15% market share and trailing rival SBC by less approximately 300,000 subscribers.