PERFORMANCE COMPARISON OF TCP FLOW CONTROL SCHEMES IN ATM NETWORKS

Abstract

A B-ISDN network based on ATM must support several kinds of transport services with different traffic characteristics and service requirements. There are neither link-to-link flow control nor error control in ATM layer. For different services, different flow control could be performed at a higher layer (i.e., transport layer). In traditional data networks, the window flow control mechanism combined with error control was used prevalently. But, the window flow control mechanism might be useless in ATM networks because the propagation delay is too large compared with the transmission rate. The scheme also suffers from rapid fluctuations in queue length, periodic packet losses and underutilization of transmission line. A simple flow control mechanism based on rate control principle was proposed for end-to-end data transport in ATM networks. In this dissertation, two algorithms have been developed based on rate control principles, with and without window control, and their performance is compared with the existing TCP-Slow Start (adaptive window control) scheme. Through simulations, the rate control mechanism is found to outperform the window control mechanism in two important areas : network efficiency and throughput.