Fairness issue and monitor-based algorithm in optical burst switching networks

Abstract

Optical burst switching (OBS) is a new paradigm proposed to efficiently support the ever-growing broadband traffic over WDM networks. In this paper, unfairness due to path length priority effect (PLPE) and burst length priority effect (BLPE) is identified in OBS networks. We propose three algorithms: M-PLPE, M-BLPE and M-PBLPE to alleviate unfairness due to PLPE, BLPE, and simultaneously PLPE and BLPE, respectively. These algorithms are all built upon a general fairness framework which we call the monitoring group drop probability (MGDP) framework for alleviating unfairness. In addition, we also propose an adaptive fairness searching algorithm, OFSA (Optimal Fairness Searching Algorithm), which can achieve optimal performance within a range of fairness objectives. Simulation results show that the new algorithms can achieve a desired fairness metric for both BLPE and PLPE, while minimizing the performance tradeoff. It is also demonstrated that the contributed fairness mechanisms actually improves throughput at high loads. In addition, none of algorithms require the specification of a fuzzy threshold. All thresholds used with the contributed algorithms are systematically updated using well thought out formulas with no fuzzy parameters required. © 2005 Elsevier B.V. All rights reserved.