IMPROVING FAIRNESS AND STABILITY IN BEST-EFFORT SERVICE - A NEW CONGESTION CONTROL ALGORITHM FOR SACK-TCP

In order to improve fairness and stability of TCP best-effort service we propose a new congestion control algorithm using packet loss inform ation obtained from Selective Acknowledgments (SACK), and evaluate its effectiveness by simulation. The proposed scheme is for an environmen t consisting of Random Early Detection (RED) routers which drop each a rriving packet with a certain probability after a threshold. The propo sed mechanism adjusts the decrease in congestion window for Fast Recov ery and the increase in congestion window per ACK during the congestio n avoidance phase according to the number of lost packets. Simulation results show that not only the bandwidth allocation fairness is improv ed but also throughput deviation is markedly reduced resulting in more stable transport capability.