Admission Control and Routing in ATM

| We address the issue of call acceptance and routing in ATM networks. Our goal is to design an algorithm that guarantees bounds on the fraction of cells lost by a call. The method we propose for call acceptance and routing does not require models describing the traac. Each switch estimates the additional fraction of cells that would be lost if new calls were routed through the switch. The routing algorithm uses these estimates. The estimates are obtained by monitoring the switch operations and extrapolating to the situation where more calls are routed through the switch. The extrapolation is justiied by a scaling property. To reduce the variance of the estimates, the switches calculate the cell loss that would occur with virtual buuers. A way to choose the sizes of the virtual buuers in order to minimize the variance is discussed. Thus, the switches constantly estimate their spare capacity. Simulations were performed using Markov uid sources to test the validity of our approach.