ATM网中ABR业务的缓存性能

Buffer Performance of ABR Service in ATM Networks

ＡＢＲ（ＡｖａｉｌａｂｌｅＢｉｔＲａｔｅ）业务是ＡＴＭ网为了充分利用网络的剩余带宽而提供的一种新型数据业务。ＡＢＲ业务采用反馈式流量控制，因而交换结点的缓存成了关系业务服务质量的关键问题。本文通过对一个简单ＡＢＲ流量控制模型的分析得出：适当地设置交换结点的缓存大小和门限值，可以保证该结点处无信元丢失，同时保证输出线路容量得到充分利用。对一个复杂模型的模拟结果表明，本文提出的缓存大小和门限值的设置方法是行之有效的。

ABR(Available Bit Rate) is a new service category provided by ATM network which intends to use the bandwidth dynamically available while maintaining the QoS of the service at the same time. Since ratebased feedback flow control is employed by ABR,buffering becomes an issue that needs intensive study. In this paper, a simple ABR flow control model is studied and it is concluded that the goals of zero cell loss and full utilization of link capacity can be achieved by choosing an appropriate buffersize and threshold of a switch buffer. And this is supported by our simulation results of a more complex network.