"[Broadband internet providers] shall not unreasonably discriminate in transmitting lawful network traffic over a consumer's broadband Internet access service." FCC 10-201, paragraph 68
The FCC says that the "Open Internet" is open because "it treats all traffic that flows across the network in roughly the same way" — so Comcast's decision to privilege its Xfinity On Demand service for Xbox 360 with free data, while requiring other apps like Netflix and Hulu to count against customer data caps, would appear to directly violate the spirit of the FCC's net neutrality efforts. Comcast says that it can enjoy this privilege because "the service travels in an IP format over our private IP network versus the public internet," but regardless of its origin, the service clearly competes with other IP-based video services at the point of consumption.
Why would Comcast choose to compete when it can stack the deck?
Gigi Sohn, head of digital rights watchdog Public Knowledge, says that Comcast's actions raise "questions not only of the justification for the caps but, more importantly, of the survival of the Open Internet." Sohn argues that "this type of arrangement is exactly the type of situation the FCC's rules on the Open Internet were designed to prevent — that an ISP juggles the rules to give itself an advantage over a competitor."
Whether or not Comcast's actions explicitly violate the FCC's rules is unclear at this time, but at any rate, it seems that the company will have a hard time arguing that this anti-competitive form of data discrimination falls under the FCC's protected category of "reasonable network management." It's certainly not the first time network providers have used trickery to create needless distinctions between IP-based services, and with major networks like Verizon and Comcast working to consolidate their power, net neutrality seems to be in as much danger on fixed broadband as it is in mobile.