Comcast Unveils Its New Traffic Management Architecture

[Guest Peter Eckersley]

Late on Friday night, Comcast filed an overview of its new traffic management arrangements with the FCC. This is the long term replacement for its controversial practice of using forged TCP Reset packets to limit the use of peer to peer protocols.

 

The new system appears to be a reasonable attempt at sharing limited bandwidth amongst groups of users. Unlike TCP RST spoofing, it doesn't explicitly discriminate against some applications, and it doesn't threaten protocol developers with interoperability problems and uncertainty about network behavior.

 

Comcast's objective here is still largely to prioritize non-P2P traffic above P2P traffic. But the criterion they use is the amount of data a cable modem sends during each 15 minute period, which is a much fairer rule than examining the traffic protocol. The way deprioritization works is simple: high priority machines get to send data, and if there is any transmission capacity left over, the low priority machines get a share of that.

 

EFF is proud that our work helped to expose Comcast's misadventures in network management last year, and we're pleased to see Comcast returning to congestion management practices that are transparently disclosed and avoid protocol discrimination.

 

The new traffic management setup should not be confused with the 250 GB/month cap which Comcast announced last month; the two will exist side by side.