Performance Evaluation of Fairness between High-Speed TCPs in Wireless Environment

摘要

Among various TCP congestion controls proposed for high delay-bandwidth networks thus far, CUBIC and Compound TCP have been implemented as default congestion control in Linux and Microsoft Windows OS, respectively. CUBIC is loss-based high-speed congestion control. Compound TCP is constructed with NewReno TCP and delay-based high-speed congestion control. When these two versions of TCP shares bottleneck link, their aggressiveness and different behaviors might fall into unfair condition. In current network environment, bandwidth of wired networks is sufficiently large and a wireless access network can be one of the most likely bottleneck points. This wireless access network has different feature than wired networks, i.e. wireless caused loss which occurs independently of congestion. In this paper, we evaluate fairness among CUBIC and Compound TCP sessions sharing high-speed wireless channel. Our simulation results show that Compound TCP is seriously suffered by CUBIC with low loss rate and this unfair condition is relieved with increase of packet loss rate because loss based CUBIC is gradually degraded by wireless caused packet loss.