You'll recall Comcast got into trouble with the FCC over their previous network management strategy.
DSL Reports also notes that Comcast has confirmed the transition completion to them. They also detail the new protocol, saying:
Comcast says that sustained use of 70% of your up or downstream throughput triggers the BE state, at which point you'll find your traffic priority lowered until your usage drops to 50% of your provisioned upstream or downstream bandwidth for "a period of approximately 15 minutes." A throttled Comcast user being placed in a BE state "may or may not result in the user's traffic being delayed or, in extreme cases, dropped before PBE traffic is dropped."Annoyingly, this comes at a time when more vendors are offering new bandwidth-hogging services such as video streaming and the like. While Comcast says only a small percentage will hit the throttling issue, there's also the bandwidth cap (admittedly, somewhat generous at 250GB) to worry about; still no promised bandwidth meter, either.