Dynamic routing and assignment of wavelength algorithms in multifiber wavelength division multiplexing networks

This paper studies multihop optical networks in which nodes employ waveleng th routing switches that enable the establishment of wavelength division mu ltiplexed (WDM) channels, called lightpaths, between node pairs. In fact, m ost optical networks are multifiber networks. The problem of dynamical rout ing and assignment of wavelength (RAW) in such networks is studied in this paper. Two resource assignment strategies, PACK and SPREAD, are proposed. B y virtue of layered-graph, routing and assignment of wavelength subproblems can be considered simultaneously. These two strategies can be used to solv e the RAW problem in networks with even links as well as that in networks w ith uneven links. Simulation shows that layered-graph-based RAW algorithms perform better than the existing ones. It also shows that SPREAD with distr ibutive use of network resources can achieve better performance than PACK w ith collective use of resources in multifiber networks. The layered-graph-b ased algorithms can effectively deal with the failure of fiber/link and nod e. By making use of the special structure of layered-graph, we propose a sh ortest path algorithm, whose complexity is lower than that of the standard shortest path algorithm.