A prompt retransmit technique to improve TCP performance for mobile ad hoc networks

In addition to research on MANET (Mobile Ad Hoc Networks) routing protocols, efforts to adopt TCP as a reliable transport protocol with some modifications have been made for the smooth integration with the fixed Internet. Basically, the standard TCP depends on the third duplicate ACK in order to retransmit a lost segment. However, when TCP operates on top of reactive routing protocols and is able to distinguish the segments transmitted over the old path from ones transmitted over a new path, TCP performance is improved by retransmitting the lost segment on the first duplicate ACK without waiting for the third duplicate ACK. As a result, it advances retransmission time thanks to our proposed prompt retransmit technique. Simulation work through GloMoSim shows that the prompt retransmit produces better TCP performance than the standard TCP.