Service Differentiation Scheme Using Two Horizons for Horizon Based OBS Networks

Takashi KODAMA  Koji KAMAKURA  Ken'ichiro YASHIRO  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.6   pp.1374-1380
Publication Date: 2007/06/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.6.1374
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Fiber-Optic Transmission for Communications
optical burst switching (OBS),  extra offset time,  service differentiation,  horizon,  multi-hop network,  

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We propose a service differentiation scheme for optical burst switching (OBS) with the scheduling algorithm Horizon. In the proposed scheme, in addition to the latest horizon used in the conventional Horizon, we introduce the second latest horizon and use them for reservation preemption. Burst priority order is perfectly guaranteed according to the burst class information informed by its control packet if the arrival time of the burst is later than the second latest horizon and earlier than the latest horizon. Since the extra offset time is no longer needed for service differentiation, the burst blocking probability and the data latency will be reduced. We assume a multi-hop network with ring topology where bursts traverse five intermediate nodes, and evaluate the performance in terms of the end-to-end and hop-by-hop burst blocking probabilities. Simulation results show that the proposed scheme can achieve service differentiation with smaller blocking probability than the extra-offset-time-based scheme with Horizon. Furthermore, we show that the proposed scheme preserves service differentiation even in multi-hop environments.