Coordinated TCP Westwood Congestion Control for Multiple Paths over Wireless Networks

Abstract—Multipath TCP (MPTCP) has just been approved by the IETF. It was designed to be fairly shared with regular TCP, so its performance is equivalent that of a regular TCP flow that on the best path for it. However, regular TCP has been proven its performance very poor in wireless networks, where packet loss often is caused by random error rather than by network congestion as in wired networks. TCP Westwood (TCPW) uses the available bandwidth estimation technique to improve TCP performance in such environment. In this work, we propose an extended version of TCP Westwood for multiple paths, called MPTCPW. To start with the analysis model of TCPW, MPTCPW is designed as a coordinated congestion con-troller between paths which allows load-balancing, fair sharing to regular TCPW at bottleneck. Our simulation results show that MPTCPW can achieve higher throughput than MPTCP in wireless environments, fairness to regular TCPW, and greater load-balancing than uncoordinated MPTCPW. I