iRGRR/PM：一种新的高速crossbar分组调度策略

iRGRR(iterative Request-Grant-based Round-Robin)算法是一种输入排队crossbar调度算法，具有硬件易实现、可扩展性强、性能优良等优点。在此基础上，该文提出一种新的高速crossbar分组调度策略iRGRR/PM(iRGRR with Packet Mode)，可以更好地支持IP分组的调度，能够被应用于高速、大容量的路由器中。与iRGRR算法相比，iRGRR/PM简化了分组输出重组模块的设计，并且提高了crossbar的带宽资源利用率。文中简单分析了两种算法间的分组时延关系，并进行了详尽的仿真研究。结果表明：在相同条件下，iRGRR/PM算法具有更高的吞吐量，尤其在非均匀业务流下能获得接近100%的吞吐量；调度长分组时，iRGRR/PM算法具有更好的时延性能。

iRGRR/PM: A New Packet Scheduling Scheme for High-Speed Crossbars

iRGRR(iterative Request-Grant-based Round-Robin) is a scheduling algorithm for input-queued crossbars, which has many good features, such as simple, scalability and fine performance. This paper proposes a new packet scheduling scheme based on iRGRR, called iRGRR/PM (iRGRR with Packet Mode), for high-speed crossbars. iRGRR/PM algorithm is appropriate to schedule IP packet, and can be used in routers with high-speed and large capacity. Compared to iRGRR, iRGRR/PM not only simplifies the design of packet output reassembly module, but also improves the bandwidth utilization of crossbar. The relation of packet delay between two algorithms is briefly analyzed, and simulation studies is done in detail. The results show that iRGRR/PM achieves higher throughput under the same circumstances, especially, reaches 100% throughput under nonuniform traffics. In addition, iRGRR/PM provides better performance of delay for larger packets.