一种多环ATM交换结构

A multi ring ATM switch fabric

提出一种新型ＡＴＭ交换结构——偏转环（ＤｅｆｌｅｃｔｉｏｎＲｉｎｇ，ＤＲ）；ＤＲ是一种没有输入缓存、无须内部加速的串行多环ＡＴＭ交换结构．它克服了传统环形交换的两个缺点：“饿死”问题和内部加速．“饿死”会导致网络吞吐率的降低，而内部加速限制了网络容量的增长．但在ＤＲ中，一个信元可能会经过多次循环才能到达正确的输出端口，会导致信元到达序列与输出序列不一致的问题；为此，提出一种窗口序列重整算法以保证信元序列的一致．最后，用计算机仿真对ＤＲ进行了性能分析，得到一些有用的结论．

This paper proposes a new packet switching architecture: Deflection ring (DR), which is a tandem multi ring switch based on the deflection routing algorithm without input buffers and internal speed up. It also overcomes the traditional token or slot based rings drawbacks of input buffers and internal speed up. Switching with input buffers will suffer from the starvation problem and decrease the network throughput while internal speed up will limit the growth of switching size. Since a packet may arrive at the destination through several recycle times, the out of sequence phenomenon appears in DR. In this paper, packet sequence integrity is guaranteed by using the packet resequence algorithm. Finally, an analysis of packet loss probability by computer simulation is also presented.