混合缓存型异步光分组交换的一种改进FF-VF算法

光纤延迟线（FDL）是异步光分组交换（OPS）采用的时域冲突解决方案，通过计算其分组丢失率（PLR）发现，在业务负载高，特别是业务负载大于0．7时，PLR性能较差。研究以FDL作为主要的常规缓存、以电存储器作为辅助缓存的光电混合缓存结构，并用改进的首选即中的填空（IFF-VF）算法调度冲突的分组，达到改善可变长OPS的PLR目的。分析和仿真结果表明，光电混合缓存和IFF-VF算法能改善可变长OPS在负载较高时的PLR性能，并减少FDL的数目。

An Improved First-Fit-Void-Filling Algorithm in Asynchronous Optical Packet Switching with Hybrid Buffering

Buffering with fiber delay line(FDL) has emerged as the current time-domain content solution for variable length optical packet switching(OPS).By calculating the packet loss ratio(PLR) of OPS with FDL buffering,we find the PLR degrade in variable length switching when the traffic load is high(i.e.,the traffic load is larger than 0.7).Then,we study the hybrid buffer structure which consists of the conventional FDL buffer as the prime buffer and a shared electronic buffer as the supplementary buffer.We put forward an improved first fit void filling(IFF-VF) algorithm for the hybrid buffer structure to improve the PLR.The results of the analysis and the simulation experiments showed the use of hybrid buffer together with the IFF-VF algorithm can greatly improve the variable length optical switch performance in terms of PLR and decrease the FDL number when the traffic load is high.