Performance Evaluation of a BatcherBanyan Interconnection Network with Output Pooling

The basic Batcher-Banyan interconnection network with input queueing is characterized by two intrinsic limitations: the head-of-line blocking severely limits the maximum switch throughput and the available bandwidth is not allocated fairly to the requesting users. A Batcher-Banyan interconnection network that overcomes these two limitations is proposed here and its performance is evaluated. The throughput limitations of the interconnection network are substantially reduced by defining pools of outputs, in which groups of outputs that offer the same service behave each as a set of servers sharing a single waiting list. Through a careful system design and a suitable priority scheme, the servers in a set can be evenly allocated to the users requesting service from the inputs of the interconnection network. For this purpose, three different solutions are proposed for the allocation of the output channels within a pool to those users requesting the same pool. Extensive computer simulation is used to evaluate the overall packet delay performance and the degree of fairness provided by each of these solutions.