波长转换器和光纤延迟线在WDM光分组交换中的结构设计和性能研究

介绍了两种新颖的光分组交换结构——MOD1和MOD2,用于解决分组冲突问题.其特点在于,MOD1共享了一组非简并的延迟线,而MOD2则是共享了一组简并的延迟线和波长转换器.研究表明,对于非突发业务,两种结构都只需要少量的延迟线即可获得理想的性能.此时,MOD1比MOD2更加能降低系统体积和成本.而对于突发业务,如果MOD1所共享的延迟线数量和MOD2所共享的延迟线和转换器的总数量相等,MOD2的分组丢弃率要远远低于MOD1.随着业务突发程度的增加,MOD2中的转换器数量也需要增加才能维持给定的分组丢弃率,但即使业务突发程度很高,MOD2在体积、成本和性能等三方面均可取得较理想的折衷.

Wavelength Converter and Fiber Delay-line Sharing in WDM Optical Packet Switches: Dimensioning and Performance Issues

Two novel switch models: MOD1 and MOD2, which employ nondegenerate fiber delay lines (FDLs) and degenerate FDLs plus wavelength converters shared among the input lines, respectively, are presented to resolve contention. For non bursty traffic, a very small number of FDLs is sufficient to obtain a reasonable packet loss probability for both models, and in this case, MOD1 is more cost effective than MOD2. While for bursty traffic, given that the total number of FDLs used for MOD1 equals to those of the FDLs and converters used for MOD2, MOD2 performs much better than MOD1 even if no converter is used. With the increase of the average burst length, the number of converters required by MOD2 needs to be increased so as to maintain a reasonable packet loss probability. However, even for the traffic with high degree of burstiness, MOD2 is still a cost effective and robust solution.