GLOBAL TRAFFIC CONTROL IN ATM NETWORKS

Abstract

In this paper, we propose a new framework for global traffic control in ATM networks which aims to maximize resource utilization and to guarantee the reliable congestion control. To do this, we first propose Global Traffic Control (GTC) mechanism which is based on harmonious cooperation of each traffic control function. GTC measures real bandwidth utilization to compensate inaccuracy of the declared mean cell rate and ii also monitors cell losses to manage input traffic load when a network approaches congestion state. We also propose new adaptive connection admission control (CAC) algorithms which calculate cell loss performance of related function blocks in a switch node using only a declared peak cell rate and an estimated mean cell rate. We measure only the mean cell rate of the aggregate cell stream in a link to estimate the mean cell rate of each virtual channel connection. We adopt a peak cell rate spacer at the User Network Interface (UNI) to compensate a cell delay variation (CDV). We will also present an approximation technique to estimate a queue length distribution of a general queue. As this technique requires negligible calculation time, it can meet the stringent requirement on the connection set-up time.