Wavelength scheduling algorithms with delayed acceptance for optical burst switching networks

In typical Optical Burst Switching (OBS) networks a reservation request is either accepted or rejected as soon as it is presented to the employed wavelength scheduling algorithm. This paper proposes a class of wavelength scheduling algorithms that process a batch of data bursts together instead of processing them one by one. When a control burst with a reservation request arrives to a free batch scheduler, the scheduler waits for a small amount of time, called the acceptance delay, before deciding to accept or reject the reservation request. After the acceptance delay has passed, the scheduler processes all the reservation requests that have arrived during the acceptance delay period, then it accepts the requests that will maximize the utilization of the wavelength channels. We describe an optimal batch scheduler that serves as an upper bound on the performance of batch scheduling algorithms. Furthermore, we introduce two novel heuristic batch scheduling algorithms. Simulation results suggest that batch schedulers could decrease the blocking probability by 25% compared to the best previously known wavelength scheduling algorithm.