A High Speed Scheduler With a Novel Scheduling Algorithm for Optical Burst Switching Networks

In this paper, a Max-CU-VF (Maximum Channel Utilization with Void Filling) channel scheduling algorithm for OBS (Optical Burst Switching) is proposed, which chooses the feasible data channel with the maximum channel utilization as the optimal one. The channel utilization defined in Max-CU-VF is the total length of scheduled BDPs (Burst Data Packet) on a data channel in a limited observing time window. The scheduling time can be decreased due to the elimination of time consumed in searching procedure in comparison with the traditional schedulers based on LAUC-VF (Latest Available Unused Channel with Void Filling). The hardware processing scheme and the corresponding hardware architecture for Max-CU-VF are designed in detail. A 16-channel Max-CU-VF based scheduler is demonstrated on FPGA (Field Programmable Gate Array). A scheduling time of 12.5 ns per BCP (Burst Control Packet) is achieved on the real-time running Max-CU-VF based scheduler. The performance of the Max-CU-VF is also compared with LAUC-VF through NS2 simulation. The results show that the burst loss ratio and the average throughput of Max-CU-VF are close to those of LAUC-VF when the load is light, and the faster Max-CU-VF outperforms the slower LAUC-VF very much when the arrival rate of bursts is over the processing speed of LAUC-VF. Therefore, Max-CU-VF is more suitable for future high speed OBS networks.