Virtual fiber configuration method for dynamic lightpath establishment in large-scaled WDM networks

Abstract

Recently, progress has been made in the Gen- eralized Multi-Protocol Label Switching (GMPLS) and Au- tomatic Switched Optical Networks (ASON) standardizations. These technologies realize construction of large-scaled optical networks, interconnection between single-domain Wavelength Division Multiplexing (WDM) networks, and direct commu- nication over multi-domain WDM networks. Meanwhile, it is known that the topology of the Internet exhibits the power-law attribute. Since the topology of the Internet, which is constructed by interconnecting ASs, exhibits the power- law, there is a possibility that large-scale WDM networks, which are constructed by interconnecting WDM networks, will also exhibit the power-law attribute. One of the structural properties of a topology that adheres to the power-law is that most nodes have just a few links, although some have a tremendous number of them. Another property is that the average distance between nodes is smaller than in a mesh-like network. A natural question is how such a structural property performs in WDM networks. In this paper, we first investigate the property of the power- law attribute of physical topologies for WDM networks. We compare the performances of WDM networks with mesh-like and power-law topologies, and show that links connected to high-degree nodes are bottlenecks in power-law topologies. To relax this, we introduce a concept of virtual fiber which consists of two or more fibers and propose its configuration method to utilize wavelength resources more effectively. We compare performances of power-law networks with and without our method by computer simulations. The results show that our method reduces the blocking probabilities by more than one order of magnitude.