Analysis of a multi-server queueing model of ABR

In this paper we present a queueing model for the performance analysis of ABR tra c in ATM networks. We consider a multi-channel service station with two types of customers, the rst having preemptive priority over the second. The arrivals occur according to two independent Poisson processes and the service times are assumed to be exponentially distributed. Each type-1 customer requires a single server, whereas type-2 customers are served in processor sharing fashion. We give a complete characterization of the joint distribution of the numbers of customers (of both types) in the system in steady state. Numerical results illustrate the effect of the high priority tra c on the service performance of the low priority tra c. AMS Subject Classi cation (1991): 60K25, 68M20, 90B12, 90B22.