光纤延迟线和可调谐波长转换器在光分组交换网络竞争解决结构中的性能分析

研究了光分组交换网络中的两种竞争解决方案.结合课题研究的进展,基于突发和非突发业务,对这两种竞争处理结构进行了深入分析,得出了几点重要结论,首先,在竞争处理上,对于非突发业务,光纤延迟线比可调谐波长转换器有效;而对于突发业务而言,可调谐波长转换器比光纤延迟线有效.其次,在突发业务下反馈式光纤延迟线结构（FFA）是一种较为理想的竞争解决结构,但对非突发业务而言,反馈式光纤延迟线和可调谐波长转换器结构（FFTA）在成本上和结构尺寸上比FFA要有效的多.随着平均突发长度的增加,FFTA中的可调谐波长转换器数目也要增加才能获得合理的分组丢失率。但无论是针对突发业务还是非突发业务,FFTA都是一种成本有效的竞争解决结构.

Performance Analysis of Fiber Delay Lines and Tunable Wavelength Converters for Contention Resolution in Optical Packet Switched Networks

In this paper, two contention resolution schemes have been studied, namely, feedback-based fiber delay lines (FDLs) Architecture (FFA) and feedback-based combined sharing of FDLs and tunable wavelength converters (TWCs) architecture (FFTA), for non-bursty traffic and bursty traffic on the basis of our optical packet switched test-bed. It is demonstrated that for non-bursty traffic, FDL is a preferable choice than TWC while TWC is a preferable one than FDL for non-bursty traffic to resolve contention in optical packet switching networks. Numeric results confirm that FFA is sufficient to obtain a reasonable packet loss probability (PLP) for non-bursty traffic, while for bursty traffic, FFTA, performs much better given that the total number of FDLs and TWCs used equals to those of FDLs used in FFA. With the increase of the average burst length, the number of TWCs in FFTA will gradually increase so as to obtain a reasonable PLP. However, even for the traffic with high degree of burstness, FFTA is still a cost effective and robust solution.