Consideration of spurious timeout in proxy for improving the performance of wireless TCP

Abstract

TCP experiences the performance degradation for various reasons in wireless network because it have been optimized to wired network. Sudden delay which is the one of the link characteristics of current wireless network can trigger spurious timeout at TCP sender. When packet transmissions are suddenly delayed, TCP responds as Go-back-N retransmissions. Timeouts that would not have occurred if the sender waited longer enough is called spurious timeout. In this thesis, we propose a proxy style solution to solve the spurious timeout problem. This method works in intermediate node between wireless network and wired network. And it does not need any changes in legacy network devices. Proposed spurious timeout detection algorithm finds out if detected timeout is spurious or not by comparing the measured inter-arrival timeout of ACK during spurious timeout period with the average inter-arrival time of ACK. It is shown that throughput and goodput of TCP which experiences spurious timeout can be improved and compensated by this proposed method.