On TCP throughput and window size in a multihop wireless network testbed

Abstract

Although it is well-known that TCP throughput is suboptimal in multihop wireless networks, little performance data is available for TCP in realistic wireless environments. In this paper, we present the results of an extensive experimental study of TCP performance on a 32-node wireless mesh network testbed deployed on the Purdue University campus. Contrary to prior work which considered a single topology with equal-length links and only 1-hop neighbors within transmission range of each other, our study considers more realistic heterogeneous topologies. We vary the maximum TCP window size, in correlation with two important MAC layer parameters: the use of RTS/CTS and the MAC data rate. Based on our TCP throughput results, wegive recommendations on configuring TCP and MAC parameters, which in many cases contradict previous proposals (which had themselves contradicted each other).