On closed loop rate control for ATM cell relay networks

A closed-loop, rate-based congestion control mechanism for ATM cell relay networks is presented. The goal of the congestion control mechanism is to guarantee the negotiated quality of service during overload conditions, and to allow a connection to exceed its negotiated throughput when there is unused capacity along its path through the network. With this control mechanism, the rate of an end system is adjusted based on both the network congestion state and whether its rate is within the negotiated parameters. The performance of this control mechanism for file transfer traffic is illustrated by results from simulations, Using a simple analytical model, the worst case buffer requirement and file transfer delay are analysed. From the analysis, conditions are derived for the rate increment, rate decrease factor and initial rate that minimize the buffer requirement and file transfer delay. From the analytical results, an adaptive rate reduction scheme is suggested to improve performance.<<ETX>>