Efficient channel scheduling algorithms in optical burst switched networks

Abstract

Abstract-Optical Burst Switching(OBS) is a promising paradigm for the next-generation Internet. In OBS, a key problem is to schedule bursts on wavelength channels whose bandwidth may become fragmented with the so-called void (or idle) intervals with both fast and bandwidth efficient algorithms so as to reduce burst loss. To date, only two scheduling algorithms, called Horizon and LAUC-VF, have been proposed, which trade off bandwidth efficiency for fast running time and vice versa, respectively.In this paper, we propose several novel algorithms for scheduling bursts in OBS networks with and without Fiber Delay Lines (FDLs). In networks without FDLs, our proposed Min-SV algorithm can schedule a burst successfully in O(logm) time, where m is the total number of void intervals, as long as there is a suitable void interval. Simulation results suggest that our algorithm achieves a loss rate which is at least as low as the best previously known algorithm LAUC-VF, but can run much faster. In fact, its speed can be almost the same as Horizon (which has a much higher loss rate). In networks with FDLs, our proposed Batching FDL algorithm considers a batch of FDLs simultaneously to find a suitable FDL to delay a burst which would otherwise be discarded due to contention, instead of considering the FDLs one by one. The average search time of this algorithm is therefore significantly reduced from that of the existing sequential search algorithms.

ARTEMIS: 40-gb/s all-optical self-routing node and network architecture employing asynchronous bit and packet-level optical signal processing

“…Since one wavelength is supported per link, specific channel scheduling algorithms [43], [52] are not required. However, in order to exploit the advantages of using timely network state information, a switching node must be capable of recording the periods when its outgoing links are reserved as a function of time, usually referred to as the "utilization profile" of the link [41].…”

Analysis of the processing and sojourn times of Burst Control Packets in Optical Burst Switches

“…With the information carried by the BCP, the node's scheduler attempts to find an available gap at which to allocate the forthcoming burst. If more than one suitable gap is found, then the Switch Control Unit (SCU) chooses one of them according to some scheduling algorithm (see Horizon [2], LAUC-VF [3], Min-SV [4] and MinVoids [5]). If all output wavelengths are occupied and no available gap is found, the data burst is then dropped.…”

Nonblocking WDM switches based on arrayed waveguide grating and limited wavelength conversion

“…Model 2 is particularly useful for asynchronous switching of optical bursts using JET (and void filling) [10], [11], as well as certain circuit-switching applications requiring specific QoS.…”