Adaptive Thresholds of Buffer to Solve the Beat-Down Problem of Rate Control in ATM Networks

摘要

ABR service is currently standardized to han- dle applications of data traffic in ATM network. As a flow control method, the rate-based flow control has been adopted and applied to manage the ABR service. Several control methods have been proposed, and the EPRCA is selected as one of the control meth- ods by the ATM Forum. EPRCA is an excellent algorithm, but when the EPRCA is applied to the ATM network, several prob- lems occur. One of the problems is the beat-down problem, which gives unfair allocation of transmission rate to connections. We propose a new control method which solves the beat-down prob- lem. We will show that, by our proposed method, (i) the ACR is given fairly to every connection compared to the conventional method, and also (ii) the throughput is fair for both long-hop and short-hop connections, (iii) the ACR is proportional to the throughput, and finally (iv) the total throughput is larger than that of the conventional method. The fairness of the throughput in (ii) is measured by the fairness index. In (iii), being propor- tional means that the allocated ACR is close to the throughput and it is measured by the proportion index. The performance is evaluated by computer simulation.