Performance of Buffered Multistage Interconnection Networks in a Nonuniform Traffic Environment

Abstract

Multistage interconnection networks (MIN) are used to connect processors to memories in shared-memory multiprocessor systems. They have also been proposed as switching fabrics in ATM switches in Broadband ISDN networks. A multistage network consists of several stages of switching elements (SE) connected by a permutation function. Since routing conflicts among packets at the SEs cause blocking and reduce the performance of the network, analytical models have been developed and simulation studies carried out for performance evaluation of MINs in the presence of uniform traffic in the network, Buffers are used at SEs to increase the performance of the network, The suitability of two existing models for possible use in the presence of a hot spot is investigated in this paper, Results show that errors from the models are large. In this paper, we propose a new and efficient Markov chain model for performance evaluation of a single-buffered Omega network in the presence of a hot spot. Results obtained from the existing models and the proposed model for the uniform and the hot spot traffic patterns are presented. It is shown that the proposed model is better than existing models in the presence of hot spot traffic, While the existing models produce small errors in the case of low blocking in the network, the errors become prominent with increased blocking. The proposed model produces accurate results in the more general case of a hot spot traffic, whereas the existing models produce accurate results only in the special case of uniform traffic.