Retransmission-Based Error Control for Continuous Media Applications

Abstract

1 Retransmission-based error recovery has been, in general, considered inappropriate for continuous media (CM) applications, because of its latency. However, retransmission is still attractive because it requires minimal network bandwidth, (less than either peak-bandwidth allocation or FEC for bursty streams) and processing cost. Despite its latency, we believe that retransmission can be used successfully in many cases, especially if playout buffering is employed. We have designed and implemented a retransmissionbased error control scheme for CM applications, which aims to provide the best possible reliability at a minimal cost, without violating the application's timing constraints. We have enhanced selective-repeat retransmission with: (1) playout buffering to increase the time available for recovery, (2) gap-based rather than timer-based loss detection to minimize loss detection latency, (3) implicit expiration of sender retransmission buffers to eliminate acknowledgments, (4) condi...