Evaluation of TCP performance over emulated DVB-RCS scenario with multiple RCSTs

This paper analyses performance of competing TCP connections when running over different return channel satellite terminals (RCSTs) and competing for DVB-RCS return link bandwidth through DAMA mechanisms. A test campaign has been performed over a Linux-based satellite emulator supporting a multi-RCST configuration in a star-based architecture, with the main goal to evaluate TCP behavior in terms of both capacity utilization and fairness. In the proposed communication scenario, TCP performance relates on the joint effect of two nested control loops: TCP congestion/rate control loop and DAMA bandwidth assignment loop. Various TCP versions have been taken into account: Reno, Vegas, Westwood+, Hybla, Cubic and Noordwijk, a new TCP specifically designed for DVB-RCS point-to-point links. Rate based capacity request (RBDC) has been selected as the access protocol.