Improving the performance of delay based protocol in delivering real time media via early retransmission

Early Retransmission (ER) has already been shown to improve TCP-SACK's performance in delivering time sensitive media. In this paper, we integrate the ER scheme into a delay-based TCP variant, namely TCP-PERT, and performs extensive ns2 simulation. Our results show that ER can also improve PERT's performance in delivering real time media by reducing the latency caused by retransmission timeouts. Furthermore, we also explored the improvement brought by employing a finegrained retransmission timer, and compared it with ER. We find out a) ER outperforms fine grained timer in a variety of conditions and b) the combination of the two can further improve performance.