iSLIP调度算法研究及其实现

目前，为提高交换系统吞吐率，设计开发高性能网络交换机或路由器内部交换结构的技术已趋成熟．但易于在硬件中实现的、高效的队列调度算法仍然是一项值得研究的重要技术．文章首先讨论了对于输入缓冲采用FIF0队列交换系统，其吞吐率主要受HOL队首阻塞的影响．然后研究了iSLIP调度算法的基本原理、迭代仲裁步骤及它在硬件中的实现．针对硬件交换转发判决这一关键问题，给出了在输入队列交换机中采用虚拟输出队列的交换结构和多优先级调度算法的硬件实现方案．最后，对isLIP算法的性能进行了分析比较，证明isLIP算法的实现方案不仅实现简单，而且具有良好的特性．

Research of an iSLIP Scheduling Algorithm and its Implementation

Current technology development makes it feasible to build extremely high throughput switch and router, which explicit employs switching high-performance fabric. However, the research of scheduling algorithm with high efficiency and easiness is still a challenge. In this paper, we firstly discuss that the factor of throughput is affected mostly by HOL (head of line blocking), for input buffered with FIFO queues per input port. Then, we introduce the principle of iSLIP scheduling algorithm, step arbitration of iSLIP for one iteration and its implementation in hardware. We describe the implementation of a scheduling algorithm for configuring crossbar in input-queued switches that support virtual output queues and multiple priorities. In the end of paper, analysis and comparison of iSLIP algorithm performance are made, the results shows its easiness to be implemented and good performance.