TCP End-to-End Performance Improvement over Wireless Networks via Early Packet Loss Recovery

A new technique is proposed that enables TCP to early detect packet losses, which cannot be detected and retransmitted using the standard fast retransmit mechanism, and to quickly retransmit those packets without waiting for a timeout to occur, thereby improving TCP performance. Early Packet Loss Recovery (EPLR) is achieved by considering the expected number of acknowledgements and the number of packets in a flight during the fast retransmit phase of the TCP mechanism. It adds a new flavor to the TCP fast retransmit and recovery mechanism without requiring any other modification to the standard TCP implementation. The scheme is modeled using the OPNET tool, and the simulation results are presented and explained. The performance of the proposed scheme is compared with that of both TCP Reno and TCP New Reno over a UMTS network. Our results show that the proposed scheme, EPLR, significantly improves the TCP performance in a UMTS environment. KeywordsTCP Throughput, Timeout Avoidance, Fast Retransmit, UMTS Network, OPNET Model