Resource efficient logical topology design for IP-over-WDM backbone networks

With the advancements in WDM technology to provide huge capacity and the Internet Protocol playing a dominant role in networking technology, IP-over-WDM network becomes a potential candidate for next generation networks. This article studies the problem of designing logical topologies for IP-over-WDM backbone networks. One important feature of IP-over-WDM networks is the reconfigurability when traffic demands change over time. If the network resource is not used efficiently, the reconfiguration can cause network disruption because no new wavelength channels (lightpaths) can be added before deleting some working channels. Moreover, more than one logical topology for different services or from different ISPs can be simultaneously implemented in an existing WDM network. Hence using resources efficiently is an important issue while designing logical topologies. In this article, we present a new approach to design logical topologies so that the network resource is used most efficiently while the network performance is guaranteed. The problem is formulated as an MILP problem. Since this MILP problem is NP-hard and can be applied for small networks only, a heuristic algorithm based on iterative optimization is proposed to solve the problem for real-size networks.