Admission control for ATM networks using rate monotonic traffic scheduling algorithm

Rate monotonic scheduling algorithm had been shown [1] to be the optimum static priority assignment scheme for an environment where packets are of variable length and a higher priority packet can preempt a lower priority one without causing any loss. It is optimum in the sense that if a set of m constant bit rate connections are schedulable (i.e., every packet is served before its succeeding packet arrives) with any static priority assignment scheme, then they are schedulable with rate monotonic scheduling algorithm. In this paper, we study the schedulability issue of rate monotonic scheduling algorithm for ATM networks where all packets are of the same length. We prove a necessary and sufficient condition for a set of m constant bit rate connections to be rate monotonic schedulable. Based on the necessary and sufficient condition, we design a simple admission control algorithm. We also present a sufficient condition which can be used for fast admission control if there are only a few possible periods for the connections.