A Real-Time Hardware-Based Scheduler For Next-Generation Optical Burst Switches

Optical burst switching (OBS) is a promising technique for next-generation optical switching networks. In traditional OBS, an entire burst is discarded when all output wavelengths are engaged at the arrival instant of the burst. A critical design issue in OBS is how to reduce burst dropping probability as a result of slow scheduling reservation or resources contention. This paper proposes a hardware-based slotted wavelength assignment pipeline (SWAP) scheduler which integrates the merits of both low computational complexity and low burst dropping probability. The key idea is to maintain all scheduled data bursts and void intervals within a scheduling time window in binary vectors. Scheduling of incoming data bursts is performed using fast hardware operations without the need to search lookup tables for void intervals on output wavelength channels. The design has been verified using Verilog HDL simulation models. The performance has been evaluated for 1 Tbps switch using Poisson traffic arrivals.