Abstract:

Congestion control is one of the cornerstones of Internet. The classical transmission control protocol (TCP) congestion control scheme, Reno, and the other two, Vegas and Fast, recently suggested upgrades for highspeed networks, are analyzed. In the comparative work, Fast's high performance is validated and its weakness, the difficulty in setting parameters, is revealed. Also, to facilitate Fast parameter setup, a measurementbased improvement is proposed. The essential idea is to introduce a macroscopic guidance layer upon end systems which will guide them to appropriate settings of number of extra packets according to periodical performance measurement on network backbone. Simulation results indicate that by realizing the target of having the bottleneck queue tend to be a fixed length, the improved Fast scheme can get a higher and steadier power, and its power will not decrease when new connections join in.

Key words: network measurement, congestion control, transmission control protocol fast, extra packets