A Fuzzy Logic Based Dual Explicit Congestion Notification Mechanism for Satellite TCP/IP Networks

In this paper, a fuzzy logic congestion control algorithm which combines the merits of the explicit congestion notification (ECN) and the backward explicit congestion notification (BECN) mechanisms is implemented in a satellite TCP/IP network environment. A roundtrip time (RTT) based decay function is proposed in order to reduce the amount of reverse traffic. This algorithm is compared with the basic fuzzy logic based dual explicit congestion notification mechanism and the random early detection (RED) based ECN mark front strategy. Performance evaluation is carried out by using both web-traffic loads and a varying number of FTP flows. Simulation results show that this algorithm reduces BECN Internet control message protocol (ICMP) source quenches significantly while maintaining virtually the same level of packet loss rate, link utilization and average goodput as in its basic variant. Simulation results further show that the RED/ECN approach registers highest packet loss rates and lowest average goodput because of the long delay in congestion notification.