Throughout this blog, we’ve continually knocked Comcast for going after users who download large amounts of data, when the real problem is bandwidth at any particular time, and for going after BitTorrent users, when download protocols are independent of bandwidth.
Both seemed to us, at the time, to have nothing to do with congestion control, and everything to do with trying to limit the capacity of the Internet to provide video which could compete with Comcast’s cable TV offerings.
But an FCC ruling against Comcast for the Sandvine-style BitTorrent throttling lead to Comcast going back to the drawing board. This time, they’re doing what they should have done in the first place.
As past of its new congestion management practices, they’ve deployed new hardware and software close to the company’s Regional Network Routers (RNRs). This hardware will flip a user from the standard “Priority Best-Effort” traffic (PBE) to lower quality of service (QoS) “Best-Effort” traffic (BE) for fifteen minutes if a subscriber surpasses a “User Consumption Threshold” of 70% of their upstream or downstream bandwidth bandwidth over a similar 15-minute period. Using more than 70% of your bandwidth for this duration is called an “Extended High Consumption State.”
What this means is that:
- There will be no changes to packet priority when the line is not congested.
- The system identifies those users who are using the most bandwidth at that moment in time.
- It places a lower priority to the packets of those heavy users. So, in an overcongested pipe, the large file downloader (FTP or BitTorrent) will have to suffer reduced speeds at higher latency (though they will still be able to get the data) while the e-mail/web/gaming/voip user will likely not see reduced throughput or increased latency.
This works. This is what we’ve been telling people. It is a platform, application, protocol agnostic method of choosing who will have service reduced during times of congestion. It attacks the limited resource – bandwidth – without attacking the unlimited resource of data. It only takes effect during times of peak usage.
Finally, Comcast gets it.