Segmentation-based nonpreemptive channel scheduling algorithms for optical burst-switched networks

Abstract

One of the key components in the design of optical burst-switched nodes is the development of channel scheduling algorithms that can efficiently handle data burst contentions. Traditional scheduling techniques use approaches such as wavelength conversion and buffering to resolve burst contention. In this paper, we propose nonpreemptive scheduling algorithms that use burst segmentation to resolve burst contentions. We propose two segmentation-based scheduling algorithms, namely, nonpreemptive minimum overlapping channel (NP-MOC) and NP-MOC with void filling (NP-MOC-VF), which can significantly reduce the loss experienced in an optical burst-switched network. We further reduce packet loss by combining burst segmentation and fiber delay lines (FDLs) to resolve contentions during channel scheduling. We propose two types of scheduling algorithms that are classified based on the placement of the FDL buffers in the optical burst-switched node. These algorithms are referred to as delay-first or segment-first algorithms. The scheduling algorithms with burst segmentation and FDLs are investigated through extensive simulations. The simulation results show that the proposed algorithms can effectively reduce the packet-loss probability compared to existing scheduling techniques. The delay-first algorithms are suitable for applications that have higher delay tolerance and strict loss constraints, while the segment-first algorithms are suitable for applications with higher loss tolerance and strict delay constraints.