MIT Technology Review

"The problem, Kuzmanovic says, is that FastTCP isn't the only attempt to improve on Reno. Other protocols have been designed that could speed file transfer while still using packet loss to monitor congestion. If those protocols send over the same line as FastTCP, they could hog the bandwidth. A protocol that senses delays could be at a disadvantage, Kuzmanovic says, since it might politely back away from congestion where more-aggressive protocols push to the point of packet loss.

Low says that his research group has been studying the issue of fairness--the question of how polite and aggressive protocols should interact. In theory, he says, it is always possible to create a fair situation, even between different types of protocols."