On June 11 Comcast announced they had dismantled a congestion management system that had been in place since 2008. This system was used to throttle data speeds for large users of residential data. The company says that their networks are now robust enough that they no longer need to throttle users and that they system wasn’t used for the last year.

Comcast implemented the congestion management system in 2008 after it had been caught throttling traffic to and from Bit Torrent. The FCC said the throttling was discriminator and ordered Comcast to cease the practice. Comcast responded to the FCC with the introduction of the congestion management system that cut back usage for all large residential data users, with what Comcast said was a non-discriminatory basis.

At the time Comcast claimed that large data users, who at that time were exchanging video files, were slowing down their network – and they were probably right. The ISP industry has been blindsided twice in my memory by huge increases in demand for bandwidth. The first time was in the 1990s when Napster and many others promoted the exchange of music MP3 files. The same thing happened a decade ago when people started sharing video files – often pirated copy of the latest movies.

To be fair to Comcast, a decade ago the number one complaint about cable company broadband was that speeds bogged down during the evening prime time hours – the time when most customers wanted to use the network. The Comcast throttling was an attempt to lower the network congestion during the busiest evening hours. Comcast says the throttling system is no longer needed since the widespread implementation of DOCSIS and improvements in backhaul have eliminated many of the network bottlenecks.

Comcast now offers gigabit download speeds in many markets. I suspect that they are relying that only a small percentage of their customers will buy and use this big bandwidth in a given neighborhood, because a significant number of gigabit users could still swamp an individual neighborhood node. I wonder if the company would reinstitute the throttling system again should their network become stressed with some future unexpected surge in broadband traffic. It’s possible that some big bandwidth application such as telepresence could go viral and could swamp their data networks like happened in the past with music files and then video.

Interestingly, the company still maintains customer data caps. Any customer that uses more than 1 terabyte in a month must pay $10 for each extra 50 gigabytes or pay $50 extra to get unlimited data. Comcast never directly said that the data caps were for congestion management, although they often hinted that was the reason for the caps.

The official explanation of the data caps has been that heavy users need to pay more since they use the network more. Comcast has always said that they use the revenues from data caps to pay for the needed upgrades for the network. But this seems a little ingenuous from a company that generated $21.4 billion in free cash in 2017 – nearly $1.8 billion per month.

Comcast is not the only ISP that has been throttling Internet traffic. All four major wireless carriers throttle big data users at some point. T-Mobile is the most generous and starts throttling after 50 GB of month usage while the other three big wireless carriers throttle after 20 – 25 GB per month.

A more insidious form of data throttling is the use of bursting technology that provides faster broadband speeds for the first minute or two of any given broadband session. During this first minute customers will get relatively fast speeds – often set at the level of their subscription – but if the session is prolonged past that short time limit then speeds drop significantly. This practice fools customers into thinking that they get the speeds they have subscribed to – which is true for the short duration of the burst – but is not true when downloading a large file or streaming data for more than a minute or two. The carriers boast about the benefits of data bursts by saying they give extra broadband for each request – but they are really using the technology to throttle data for any prolonged data demands.