Analytical modelling of shared buffer ATM switches with hot-spot pushout under bursty traffic

Asynchronous Transfer Mode (ATM) shared buffer switches have numerous advantages such as relatively high throughput and good buffer utilization, and they are increasingly favoured in recent VLSI switch designs. But under nonuniform traffic, the performance degrades dramatically due to the monopolization of the buffer by some favoured cells. To overcome this, restricted types of sharing and Hot-Spot-Push-Out (HSPO) have been proposed, and the latter has been shown by simulation to perform better in all situations. In this paper we construct an analytical model for the first time, for evaluation of a shared-buffer ATM switch with HSPO under bursty traffic. We use an urn model to approximate the effects of pushout, while keeping only four state-variables, and our results give a very good agreement with simulation.