ATM网络中CBR业务排队性能分析

Queueing Analysis of CBR Traffic in ATM Networks

分析了ATM网络中CBR业务排队性能 ,给出了一种简单的计算信元丢失率和信元平均时延的表达式 .分析结果表明 ,一方面在较小的缓冲区容量下 ,即使CBR业务被分配的带宽大于等于其峰值速率 ,也还存在着较大的信元丢失 ;另一方面 ,当复用的CBR业务源数目很大时 ,只需要分配相对较小的缓冲区容量就可以满足十分低的信元丢失率要求 .该结果对于ATM设备中相应的缓冲区设计。

The problems of CBR (constant bit rate) traffic in ATM (Asynchronous Transfer Mode) networks are analyzed, and simple methods to calculate the cell loss ratio (CLR) and mean cell delay are derived. It is shown that on the one hand, even if a BW (bandwidth) equal to or larger than the Peak-Cell-Rate (PCR) is allocated for the CBR traffic, a large CLR may result in a small buffer system; on the other hand, with only a comparatively small buffer a very small CLR can be guaranteed when a large number of CBR sources are multiplexed. These results are important for the buffer design, BW allocation and connection admission control in ATM equipment.