A Single Retry Multirate Loss Model for Impatient Calls

We consider a link that services Poisson arriving calls from different service-classes. Calls have a peak-bandwidth requirement and an exponentially distributed service time. If there is no available bandwidth in the link, a call is blocked but retries with a lower bandwidth requirement at the cost of an increased service time. To allow for the fact that a blocked call may leave the link due to impatience, we consider the case that a blocked call retries with a probability. To determine call blocking probabilities, we prove an approximate but recursive formula which provides quite satisfactory results compared to simulation.