Virtual topology reconfiguration for wide-area WDM networks

We propose several algorithms that reconfigure virtual topologies in wide area wavelength-routed optical networks. The reconfiguration algorithms attempt to keep the the network availability as much as possible during the reconfiguration process. For this purpose, a lightpath is taken as the minimum unit of reconfiguration, which is an all-optical wavelength-division multiplexed (WDM) channel. The proposed algorithms are evaluated by using an NFSNET-like network model with 16 nodes and 25 links. The results show that very simple algorithms provide very small computational complexity but poor performance, i.e., bad network availability, and that an efficient algorithm provides reasonable computational complexity and very good performance. More complex algorithms may improve performance somewhat further but have unrealistically large computational complexity.