Multipath TCP in lossy wireless environment

Abstract — Random loss in wireless ad hoc nets derives from two main causes: lossy wireless channels and node mobility. Breakage and loss can significantly degrade the performance of network protocols, especially TCP. Recently, several schemes have been proposed to protect TCP from mobility induced link breaks by freezing TCP state when a link break is detected. TCP freeze however does not help with high channel loss due to random interference. Multipath solutions had been attempted to protect TCP from mobility, but with no success. In this paper, we address lossy channels. We repropose multipath routing to enhance TCP performance in lossy environment with heavy interference. To combat extremely high packet loss rates, we propose to duplicate each TCP packet and transmit a copy over each of the multiple paths provided by routing. Since each packet has several copies transmitted over multiple paths, the chance that all copies are lost is much reduced. Through simulation investigation, we observe that our scheme can improve TCP performance in a very lossy environment. This advantage persists even in presence of mobility. I