Experimental Evaluations of Gentle HighSpeed TCP for Long-Fat Networks

It is well-known that TCP Reno cannot provide satisfactory performance in high-speed long-delay networks. As a means addressing this problem, gentle highspeed TCP (gHSTCP) has been proposed in Z. Zhang et al. (2004). However, its effectiveness has only been demonstrated in simulation experiments. In the present paper, a refined gHSTCP algorithm is proposed for application to real networks. The performance of the refined gHSTCP algorithm is then assessed experimentally. The refined gHSTCP algorithm is based on the original algorithm, which uses two modes (Reno mode and HSTCP mode) in die congestion avoidance phase and switches modes based on RTT increasing trends. The refined gHSTCP algorithm compares two RTF thresholds and judges which mode will be used. The experimental results demonstrate that gHSTCP can provide a better tradeoff in terms of utilization and fairness against co-existing traditional TCP Reno connections