Performance of the asynchronous optical packet switch scheduling with hybrid queue buffering

Buffering with fiber delay lines (FDLs) has emerged as the current time-domain content solution for asynchronous optical packet switching (OPS). By calculating packet loss ratio (PLR) of OPS with FDL buffering, we find the PLR degradation in asynchronous 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 fiber delay line (FDL) buffer as the prime buffer and a shared electronic buffer as the supplementary buffer. We put forward an improved first fit void filling algorithm for the hybrid buffer structure to improve the PLR. The results of the analysis and the simulation experiments show the use of FDL buffer together with the electronic buffer can greatly improve the optical switch performance in terms of PLR and decrease the FDL number when the asynchronous traffic load is high.