Switch Port Allocation in WDM Networks with Hybrid Optical-Electronic Switching Nodes


IEICE TRANSACTIONS on Communications   Vol.E94-B   No.4   pp.928-939
Publication Date: 2011/04/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.928
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Fiber-Optic Transmission for Communications
WDM network,  electronic switch,  optical switch,  optical bypass,  traffic grooming,  

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We investigate the problem of switch port allocation in WDM networks that use the hybrid optical-electronic switching node architecture. The objective is to support given traffic demands while minimizing the number of electronic switch ports used, or equivalently minimizing the number of established lightpaths. We first formulate the problem as a mixed integer linear programming (MILP) problem. However, due to the high computational complexity of exact optimization, we develop a simulated annealing (SA) algorithm to get an approximate solution. Results from the SA algorithm demonstrate that, compared to the optical-electrical-optical (O-E-O) node architecture, a WDM network that employs the hybrid switching node architecture requires many fewer lightpaths. We also develop a lightpath assignment heuristic which requires much less computation time than the SA algorithm while maintaining close objective values. The lightpath assignment heuristic is used to investigate the switch port allocation behaviors. Simulation results show that nodes with high degrees or with small average node distances require large numbers of optical switch ports. Moreover, nodes with large amounts of terminate (originated/destined) traffic require large numbers of electronic switch ports. Since the lightpath assignment heuristic requires small computation time, it can be used in the network design process in which a large number of network scenarios must be considered.