Average RTT HSTCP: Improving Fairness in High-Speed Networks

Traditional TCP congestion control has poor performance in high-speed networks because of its slow response with large congestion windows. HSTCP has been proposed as one of the possible ways to better utilize the networks with high bandwidth-delay products. Experiments revealed that HSTCP can use the bandwidth more sufficient than current TCP, but it has severe RTT unfairness. In this paper, we first investigate the RTT unfairness through mathematical analysis and simulation studies, and then we add a fair factor to the HSTCP to decrease the difference of window increase caused by different RTT. Experiments show that the modified algorithm can guarantee the bandwidth fairness of HSTCP flows and reduce the packets loss rate.