An effective dynamic reconfiguration algorithm for IP over WDM networks

WDM (Wavelength Division Multiplexing) technology can provide multiple wavelengths on a fiber. IP directly over WDM (or IP over WDM) has become the hot topic of industry. A promising approach for building an IP over WDM network is that a logical network consisting of the wavelength channels (lightpaths) is built on the physical WDM network. Then, IP traffic is carried on the logical topology, by utilizing the MPLS (Multiple Protocol Label Switching) or GMPLS (Generalized MPLS). When the traffic demand pattern changes in the IP layer, the network performance may become poor. In order to improve the network. performance, the virtual topology can be reconfigured to suit the changing traffic patterns. In this paper, dynamic slowly-adaptation scheme (e.g. tearing down a lightpath that is lightly loaded or setting up a new lightpath when congestion occurs) is adopted. How to select the source and the destination nodes of the new lightpath to be added and the underutilized lightpath to be deleted if it is necessary to do so is our key issue. Four selection ways are developed. These ways are evaluated through detail simulations and various performances are investigated.