Performance comparison of transport control protocols over mobile ad hoc networks

In mobile ad hoc networks, researches have been concentrated on the implementations and performance comparisons of routing protocols. Few attention was paid to the performance of the end-to-end TCP connection. In this paper, we study the route breakages caused by mobility and their effects on the performance in different TCP implementations (e.g. Tahoe, Reno, NewReno and Sack). Our performance simulation shows that current TCP implementations can not guarantee a stable performance because they are impossible to distinguish a packet loss caused by congestion or by route breakage. A new metric, Weighted Route Length is introduced in the comparison of TCP performance in the mobile ad hoc network. We demonstrate that TCP Sack generally performs better than Reno, NewReno and Tahoe. The effects of interactions among routing, MAC and TCP protocol are also discussed briefly. This paper presents the simulation results of four TCP implementations and provides comparisons based on some important performance metrics (throughput, goodput, transfer time) and multimedia QoS measurement (average packet delay).