The TCP SACK-aware snoop protocol for TCP over wireless networks

Abstract

TCP continues to be the most important transport layer communication protocol. Several solutions have been proposed to address the known problems that TCP faces when running over wireless networks. Of these solutions, the Snoop protocol, a link layer retransmission strategy, has been shown to be the most effective. However, not all TCP versions have been analyzed using the Snoop protocol. In fact, we recently showed that TCP Vegas and TCP SACK exhibit opposite performance results when utilized with and without the Snoop protocol. In this paper we analyze this behavior and introduce the TCP SACK-aware Snoop protocol for wired cum wireless networks. We show how to make the Snoop protocol TCP SACK-aware and why using the Snoop protocol is in fact worse than not using any mechanism at all. The TCP SACK-aware protocol improves the performance of TCP SACK by around 30% compared to the plain Snoop protocol and by about 8% in an environment where no TCP enhancing mechanism is in place.