The US Court of Appeals for the District of Columbia has told the Federal Communications Commission that it can’t make broadband providers treat all the Internet content and services traveling over their networks the same.

Comcast, the big cable company, challenged the FCC’s right to stop it from blocking its broadband subscribers from using BitTorrent file-sharing technology.

If its authority is questioned, the decision could potentially throw a monkey wrench into the agency’s plans for a massive national broadband network paid for in part by tapping the federal fund that subsidizes phone service in poor and rural communities.