输入缓冲交换机的缓冲管理方案研究

Study of Buffer Management of Input-Buffered Switches

交换机中设置缓存的目的是暂时保存由于资源冲突而无法立即被交换到输出链路的数据包/信元,缓存的组织和管理方式对交换机的性能具有直接的影响。文章通过模拟实验比较了常用于共享存储器交换机和输出缓冲交换机的缓存管理方案对具有有限容量输入缓冲交换机性能的影响。实验结果显示:交换机性能指标,如吞吐率、延迟、丢包率等对缓冲存在相互矛盾的要求,需要进行折衷、平衡。

The VOQ switch can forward traffic at line rate without internal speedup while eliminating HOL blocking in single FIFO queueing switches, so it has recently received increasing attention of many designers and is considered as the best solution for high performance switches. The function of buffers in switches is to store the packets or cells temporarily which can not be forwarded to the output links due to resource contention. The fashion of buffer organization and management has direct influence on switches performance. In this paper, we compared effects of various buffer management schemes on the performance of input buffered switches with finite buffer capacity by simulations. The results show that the performance indexes, such as throughput, delay, packet lost ratio, have inconsistent requirements for buffer with each other and tradeoff is necessary in resource management.