Avoiding Spurious TCP Timeouts in Wireless Networks by Delay Injection

Ths transmission control protocol (TCP) has been designed to provide reliable transport of packets by adjusting the transmission rate to the network congestion level. While TCP can adapt to small fluctuations in the delay between the sender and the receiver, adverse effects (most importantly spurious timeouts) have been observed under large delay variability). In this paper, we exhibit the presence of such delay spikes in wireless networks and discuss their possible origins. We then investigate a new methodology for avoiding spurious TCP timeouts by injecting additional random delay in the network. Different algorithms for the delay injection are presented and we assess their relative performances and merits through simulations based on round-trip time (RRT) measurements in a live GPRS network. One of the attractive features of the new methodology is that it does not require any changes to the TCP protocol.