Microscopic behaviors of TCP loss recovery using lost retransmission detection

As today´s networks evolve towards an IP-based integrated network, the role of transmission control protocol (TCP) has been increasing as well. As a well-known issue, the performance of TCP is affected by its loss recovery mechanism that is comprised of two algorithms; fast retransmit and fast recovery. Although retransmission timeout (RTO) caused by multiple packet losses can be avoided by the modified fast recovery algorithm of TCP NewReno or selective acknowledgement (SACK) option, RTO cannot be avoided if a retransmitted packet is lost. To cope with the problem, lost retransmission detection (LRD) has been proposed for each TCP in B. Kim and J. Lee (2004). In this paper, we evaluate the LRD algorithm by tracing TCP sender´s behaviors for several scenarios where a retransmitted packet is lost. In addition, we consider the ´conservation of packets´ rule to advocate that LRD does not violate fairness with TCP connections that do not support the LRD algorithm.