Cable operator Comcast is launching a legal battle to overturn a decision by telecoms regulator the Federal Communications Commission (FCC) to impose sanctions after it was found to be contravening net neutrality rules. The watchdog said last month that Comcast has been blocking file sharing internet applications such as BitTorrent and this goes against an FCC principle which says all internet traffic should be treated equally. The Commission ordered Comcast to stop blocking the traffic by the end of this year and wants the firm to provide it with more details of its network management practices. Comcast has now appealed the decision, saying its move to throttle file sharing traffic is necessary to stop certain high bandwidth users from causing congestion on its networks. The cableco’s lawsuit hinges on the argument that the FCC has no right to impose sanctions based on its general principles rather than formal rules, The Wall Street Journal reports.