Effectiveness of loss labeling in improving TCP performance in wired/wireless networks

The current congestion-oriented design of TCP hinders its ability to perform well in hybrid wireless/wired networks. We propose a new improvement on TCP NewReno (NewReno-FF) using a new loss labeling technique to discriminate wireless from congestion losses. The proposed technique is based on the estimation of average and variance of the round trip time using a filter, called flip flop filter, that is augmented with history information. We show the comparative performance of TCP NewReno, NewReno-FF and TCP Westwood through extensive simulations. We study the fundamental gains and limits using TCP NewReno with varying loss labeling accuracy (NewReno-LL) as a benchmark. Lastly our investigation opens up important research directions. First, there is a need for a finer grained classification of losses (even within congestion and wireless losses) for TCP in heterogeneous networks. Second, it is essential to develop an appropriate control strategy for recovery after the correct classification of a packet loss.