Professor Ed Felten tells Comcast to stay after class and clean erasers:
There are well-established mechanisms for dealing with traffic congestion on the Internet. Networks are supposed to respond to congestion by dropping packets; endpoint computers notice that their packets are being dropped and respond by slowing their transmissions, thus relieving the congestion. The idea sounds simple, but getting the details right, so that the endpoints slow down just enough but not too much, and the network responds quickly to changes in traffic level but doesnâ€™t overreact, required some very clever, subtle engineering.
Indeed, if everybody was nice, polite, and well-behaved, the Internet’s traffic management features would be enough for Comcast and everybody else. And we wouldn’t need jails, or police, or traffic signs because everybody would just be good. That’s the end-to-end world, and it exists nowhere in this universe.
What does exist is a program called BitTorrent that allows the user to set targets for bandwidth consumption in both the upstream and the downstream direction, and strives to reach those limits by any means necessary. If the link is slow, it opens additional connections. If TCP is slow, it uses UDP. If its connection requests are filtered, it encrypts them. If its port is blocked, it uses a different one. It worms through firewalls and works around NATs. Nothing in the conventional arsenal of TCP effectively limits BitTorrent’s appetite for bandwidth, it’s all up to the user. And if he’s a hog, it’s out of control.
The long-term solution to congestion is to increase bandwidth, and there is no cheaper way to to that than to expel bandwidth hogs. Comcast doesn’t always go that far, and for that they get blasted in the blogs. Life is not fair.
Fundamentally, the problem that Comcast addresses with its TCP RSTs isn’t an Internet problem, it’s an Intranet problem, as in the DOCSIS network inside Comcast doesn’t handle high loads of upstream traffic without going unstable. This isn’t a problem that the Internet can address, although TCP does provide Comcast with a knob to turn.
H/T Tech Lib.