This work considers switching fabrics with distributed packet routing to achieve high scalability and low costs. The considered switching fabrics are based on a multistage structure with different re-circulation designs, where adjacent stages are interconnected according to the indirect n-cube connection style. They all compare favorably with an earlier multistage-based counterpart according to extensive simulation, in terms of performance measures of interest and hardware complexity. When queues are incorporated in the output ports of switching elements (SE’s), the total number of stages required in our proposed fabrics to reach a given performance level can be reduced substantially. The performance of those fabrics with output queues is evaluated under different “speedups” of the queues, where the speedup is the operating clock rate ratio of that at the SE core to that over external links. Our simulation reveals that a small speedup of 2 is adequate for buffered switching fabr...
Nian-Feng Tzeng, Ravi C. Batchu