FastSoft to commercialize Fast TCP

eWeek.com writes:

FastSoft will address the lag time in transmitting large files using industry-standard FTP with its new Aria appliance. It is an asymmetric device that requires no companion appliance or software client at the other end of the connection.

Aria is based on Fast TCP, a new TCP congestion avoidance algorithm developed at the California Institute of Technology, and compatible with existing TCP algorithms, requiring modification only to the computer which is sending data.

Most current TCP congestion control algorithms detect congestion and slow down data transfer when packets are being dropped, so that the average sending rate (TCP window) depends on the loss probability. However, packet loss is not the best indicator for congestion. Some transmission channels (e.g. wireless air interfaces) have inherently high packet loss. Fighting such lossy channels with congestion control mechanisms has the clear disadvantage that throughput is reduced. Fast TCP, on the other hand, adjusts the data rate based on the number of packets in packet queues throughout the network, and these queues are measured by comparing the actual Round-Trip-Time with the Round-Trip-Time in case of no queuing.

Similar TCP implementations are used in the products of wireless infrastructure vendors (e.g. Cisco, Ericsson, etc.) who often call this feature Active Queue Management.