Generic closed product-form queueing network modeling of window protocols with error recovery

摘要

This paper presents a generic performance model using a closed product-form queueing network and an approximate analysis, which reflects error recovery procedures defined in the existing window protocols. The proposed analysis makes it possible to examine the effect of the key components of the error recovery procedures, and protocol parameters such as window size, on the performance of a window flow controlled communication system. Compared between the analytical results and the simulation results, the approximation errors are shown to be within a reasonable range when packet length is assumed to be independence. We show that an ARQ mechanism is effective for packet loss detection, and the multiple-NACK scheme improves the performance for high packet loss probabilities. Furthermore, we investigate the effect of window size on the effective throughput deterioration caused by retransmissions, and the rate of increase of mean end-to-end delay. From a discussion of numerical results and feasibility, we show that the appropriate window size is given by the smallest integer greater than or equal to the result of the division of the mean round-trip delay by the mean service time of a bottleneck queue. In particular, in the case of a go-hack-N retransmission scheme, we observe that the appropriate window size yields the least possible performance degradation in situations with a high probability of packet loss