A Group Scheduling Algorithm with Void Filling for Multi-Channel in OBS Networks

Abstract

The scheduling in OBS networks is an important operation in reducing the packet loss probability and exploiting the bandwidth of optical fibers. There are two main scheduling approaches: the online scheduling, in which a burst header packet (BHP) arriving at an OBS core node reserves immediately the needed resources for its following burst; and the group scheduling, in which the BHPs arriving in a timeslot schedule the resources for their corresponding bursts together. For the second approach, there were several proposals as OBS-GS, MWIS-OS and LGS, but all of them only consider the group scheduling on one data channel. A few other suggestions as GreedyOPT and LGS-MC consider the group scheduling for multi-channel in support of full wavelength converters. However, these group scheduling algorithms haves not really best exploited the bandwidth of data channels yet, and then have not reached an optimal solution. This article proposes a new group scheduling algorithm which is capable of mining the voids created between the bursts scheduled before on data channels, therefore, their bandwidth is exploited more efficiently.