Wireless TCP Enhancements Using Multi-level ECN

Due to the increasing demand for mobility among the Internet users, there is a urgent requirement to identify and solve the deficiencies in the wireless domain. One such urgent problem is the poor performance of TCP over wireless links. TCP still being the only protocol used in the Internet for reliable transfers, the assumptions made by TCP in the wired domain are not valid in the wireless domain. To enhance the performace of the TCP in the wireless domain, we need to differentiate the 'congestion loss' from the 'wireless loss'. We find that the previous attempts in this direction make unjustified demands from the network or the accuracy of the schemes are inadequate. We are convinced that reliable transport is a end-to-end semantic and other network components should not be burdened with this work. In this paper we propose a scheme called the 'Source-Centric Congestion Filtering', based on the MECN protocol, which tries to differentiate the losses based on the network feedback. Our simulations using the NS-2 simulator shows that our protocol has very less percentage of error and performs better than most of the other end-to-end TCP variants.