一种新的高性能ATM共享存储交换单元

A New High-Performance Shared-Memory Switching Element

ＡＴＭ交换单元中，可选用三种基本排队策略一输入排队、输出排队和共享存贮排队。根据平均信元时延、吞吐量和信元丢失概率性能，最佳的排队策略是并享存储排队。由于传统的共享存储交换单元必须缓冲经过交换单元的所有信元，因此交换单元的吞吐量和信元丢失概率性能仍不理想，特别是对于大规模交换单元情况更是如此。本文提出了一种新的高性能共享存储交换单元，称为阻塞信元共享存储（ＢＣＳＭ）交换单元。顾名思义，ＢＣＳＭ仅仅缓冲交换单元输入端口的阻塞信元，而不必缓冲经过交换单元的所有信元。均匀业务下的分析结果证明，ＢＣＳＭ交换单元比一般共享存贮交换单元具有更好的性能。

Three kinds of basic queueing policy-input, output and shared-memory queueing can be selected for ATMswitching elements. According to performances of the msc cell delay, throughput and cell loss proboility, the best qUeueing policy is the shared -- memory qUeueing.Because traditonal shared-memory switching elementS have to buffer all cells Passing troughthem, their Performances Of the mean cell delay and cell loss probability ramain unsatisfactory, especially for large size switchingelements. This paper p￣s a new high -- airforce switching element with a new shared-memory queueing policy, which iscalled blocked -- cells shared -- memory qUeueing (BCSM). As the name m￣, instead of buffering all cells through it, the BCSMswitching element only bibers the blocked cells at its input POrts. Theoretic analyses results Under the un￣ ￣c model PrOVethat BCSM switching elementS have better performances than shed-memory switching elements.