The Federal Communications Commission's decision to sanction Comcast for blocking peer-to-peer traffic should be vacated because the order "enforced mere policy -- not any provision of federal law," Comcast argues in its latest court papers.

Comcast is appealing the FCC's groundbreaking ruling that the company's traffic-shaping techniques violated a 2005 Internet policy statement. That document says that networks should treat all lawful applications equally, and that consumers should have access to all lawful content of their choice.

The cable company is now asking the D.C. Circuit Court of Appeals to reverse the FCC's ruling on the grounds that the policy statement isn't an enforceable regulation.

In its final appellate brief, filed this week, Comcast argues that it had no reason to believe that blocking peer-to-peer traffic was unlawful, given that the 2005 policy statement was never codified. "The order violated basic rules of fair notice," Comcast says.

Comcast also argues that the FCC's decision last week to begin the process of crafting net neutrality rules proves that the agency previously lacked the authority to impose sanctions for neutrality violations.

The FCC didn't fine Comcast, but ordered it to stop throttling peer-to-peer traffic. As a practical matter, the order had little effect on Comcast, because the company had already committed to shifting to a protocol-agnostic traffic management system.

A variety of industry observers have filed papers in the appeal. One brief, filed by law professors earlier this month, warns the appellate court that a decision to reverse the ruling could hinder the growth of the Web. "Practices such as Comcast's -- which could be widely adopted and expanded if the court vacates the [FCC's] order -- would threaten application innovation by raising its costs," the academics argue.

The FCC argues that it has the power to create policy through adjudications, such as the Comcast proceeding. The agency also argues that its 2005 Internet policy statement served to put Comcast on notice that it shouldn't tinker with traffic.

The case is slated to be argued at the D.C. Circuit Court of Appeals in January.

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