An algorithm for connection precedence and preemption in asynchronous transfer mode (ATM) networks

This paper describes an algorithm for use in asynchronous transfer mode (ATM) networks that allows connections to be admitted on the basis of precedence. While currently employed ATM prioritization schemes grant priority to cells in the network, high precedence connections may be locked out when the requested network resources are unavailable. The algorithm described in this paper considers connection precedence when making the admission decision and preempts lower precedence connections when the requested resources are unavailable. No modification is required to the deployed connection admission control (CAC) algorithm and the network manager may configure the precedence assignment and preemption policies for network-specific optimization. Through software simulation, it was shown that higher precedence connections experienced a significantly improved rate of admission at the expense of preempting lower precedence connections. The tradeoff was increased connection establishment processing time.