DIFFERENTIATION OF WIRELESS AND CONGESTION LOSSES IN TCP

Abstract

Transmission Control protocol (TCP), the most widely used transport layer protocol on Internet, has attained significant maturity over the last few years and the popularity of wireless communication and computing systems is on the rise. Efforts are underway to extend TCP to wireless to enable smooth integration of the two technologies. Since TCP was developed for wired medium, wireless medium posed an altogether a new set of challenges to TCP. For this reason TCP requires improvements or modifications. TCP assumes every packet loss is a congestion loss hence decreases the sending rate. This will decrease the sender's throughput when there is an appreciable rate of loss due to link error. This issue is significant for wireless links. We present an extension of TCP-Casablanca which improves TCP performance over wireless links. We proposed a new discriminator which not only differentiates congestion and wireless losses, but also identifies the congestion level in the network, i.e., whether the network is lightly congested or heavily congested and throttles the sender's rate according to the congestion level in the network.