Performance Evaluation of Selected Packet Dispatching Schemes for the CBC Switches

The CBC stands for the Central-stage Buffered Clos-network. This kind of switching fabric was proposed and theoretically evaluated by F. Wang and M. Hamdi. In this paper new packet dispatching schemes for the CBC switches are proposed and evaluated. We study three such schemes, called RGNA (Request -- Grant with No Association), RGAM (Request - Grant with Associated output Modules), and RGAP (Request - Grant with Associated output Ports). Our research is aimed at finding an answer to the question: what kind of packet dispatching scheme should be used in the CBC switch to achieve very good performance in terms of throughput, cell delay and central buffers size. The uniform and nonuniform traffic distribution patterns are used to evaluate the performance of the CBC switch. Using computer simulation we try to fill an important gap between the theory and practical implementation of interesting switch architecture.