Practical crossbar scheduling algorithms for CIOQ switches such as PIM and ¢ -SLIP, can perform poorly under extreme traffic conditions, frequently failing to be workconserving. The common practice of evaluating crossbar scheduling algorithms according to the packet delay under random admissible traffic tends to obscure significant differences that affect the robustness of different algorithms when exposed to extreme conditions. On the other hand, algorithms such as LOOFA with provably good worst-case performance, don’t lend themselves readily to high performance implementation. We advocate evaluating crossbar scheduling algorithms using targeted stress tests which seek to probe the performance boundaries of competing alternatives. Appropriately designed stress tests can reveal key differences among algorithms and can provide the insight needed to spur the development of better solutions. In this paper, we introduce the use of stress testing for crossbar scheduling and use it to...
Prashanth Pappu, Jonathan S. Turner