Converter-Aware Wavelength Assignment in WDM Networks with Limited-Range Conversion Capability

Quang-Dzung HO  Man-Seop LEE  

IEICE TRANSACTIONS on Communications   Vol.E89-B   No.2   pp.436-445
Publication Date: 2006/02/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.2.436
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Switching for Communications
lightpath,  wavelength assignment algorithm,  wavelength conversion,  RWA,  WDM,  

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In wavelength-routed optical networks, wavelength converters are considered as one of the most critical network resources because they can significantly reduce the blocking probability, but still remain quite expensive. Unfortunately, previous wavelength assignment algorithms have seldom considered their presence. Therefore, in this paper, we propose a novel dynamic algorithm that can minimize the number of wavelength translations. Our algorithm establishes lightpaths by connecting a minimum number of wavelength-continuous segments. We mathematically prove the correctness of our algorithm. Then, we carry out extensive performance evaluations over three typical topologies with full-range or limited-range converters to compare our proposed algorithm with first-fit and most-used algorithms. The simulations show that, to obtain similar blocking performance, our algorithm requires much fewer converters, or the same number of converters but with smaller conversion ranges. From another perspective, with the same conversion capacity, our algorithm can significantly improve the blocking performance. Our algorithm is also scalable due to its polynomial time complexity and insignificant local signaling overhead.