A Study on Flexible, Reliable, and Scalable Wavelength-Routed Optical Networks

Reconfiguration of logical topologies with minimum traffic disruptions in reliable WDM-based mesh networks, " Photonic Net-Virtual fiber configuration for dynamic light-path establishment in large-scaled optical networks, " Photonic Network Communi-Proposal of procedures to reconfigure logical topologies in reliable WDM-based mesh networks, " in Proceedings of SPIE Asia-Virtual fiber configuration method for dynamic lightpath establishment in large-scaled WDM networks, " in Proceedings of Management of logical topologies for dynamically changing traffic in reliable IP over WDM networks, " Technical Report of Performance analysis of soft-state signaling protocols in wavelength-routed networks, " Technical Report of IEICE (PN2005-46),. ii. Preface The volume of the Internet traffic has been increasing rapidly due to the growth of the population of Internet users and the popularization of online applications and services that require high bandwidth, such as voice chat, video streaming, P2P file sharing, and grid computing. To accommodate the Internet traffic, the capacity of backbone networks has been enhanced by WDM (Wavelength Division Multiplexing). WDM is the technology that multiplexes and carries signals of different optical wavelengths in a single optical fiber. Although WDM resolves the shortage of the fiber capacity, the nodes connected to the WDM-capable fiber become the bottlenecks because those nodes must convert received signals between the optical format and the electric format and process the signals at the speed of light. Therefore, WDM-based networks are extended to wavelength-routed networks by installing optical switches in the nodes. Wavelength-routed network is based on the circuit-switching paradigm; nodes are connected with dedicated virtual circuits called lightpaths. By configuring lightpaths, a logical topology is constructed over a wavelength-routed network. A wavelength-routed network consists of data plane and control plane. Lightpaths are established on the data plane including optical switches and fibers while those light-paths are managed in the control plane. There are two standard control architectures for wavelength-routed networks, GMPLS (Generalized Multi-Protocol Label Switching) and ASON (Automatically Switched Optical Network). These architectures have been being designed so as to interconnect multiple wavelength-routed networks. The progress of the standardizations of these architectures grows the scale of wavelength-routed networks. As a result, large-scaled wavelength-routed networks are comprised. Due to this enlargement, the volume of the traffic carried over the networks increases. The probability that a network. v. failure occurs gets higher because of the increase of the number of network components. In addition, the amount of the information for managing networks also increases. Hence, flexibility, reliability, and …