Modelling and Performance Analysis of Shared Buffer ATM Switches with Hot-Spot Pushout under Bursty Traffic

Shared buffer switches have many advantages such as relatively low cell loss rate and good buffer utilization, and they are increasingly favoured in recent VLSI switch designs for ATM. However, their performance degrades dramatically under nonuniform traffic due to the monopolization of the buffer by some favoured cells. To overcome this, restricted types of sharing and Hot-Spot-PushOut (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 that is much simpler than the previous one, for evaluation of a shared-buffer ATM switch with HSPO under bursty traffic. We balance the relative queues to approximate the effects of pushout, while keeping only four state-variables, and our results give a very good agreement with simulation.