Research On Survivable Protection Algorithms In WDM Mesh Optical Networks

As communication services explosively increase all over the world, WDM (Wavelength Division Multiplexing) mesh optical networks, with enormous data and services transmission capabilities, have become the most promising communication backbone network infrastructures currently and in the future. In these backbone networks, any failure of network components (fiber links or nodes) may lead to large amounts of service connection interruptions and severe network blocking, cause vast economic loss to both users and operators. Therefore, survivable protection technologies for optical networks are always the research focus of optical communication field. Considering dynamic service environment in WDM mesh optical networks, the author in this dissertation studies survivable protection issues on the following aspects:survivable protection against double-link failures, survivable protection against double-node failures, survivable protection for translucent optical networks, and survivable protection for energy-efficient optical networks.In order to facilitate the readers to comprehend the research work of this dissertation, in Chapter1, the author introduces the relevant technologies and developments survey of WDM optical networks, next puts forward the optical network survivability issues and introduces survivable protection technologies and their development route.In Chapter2, the author studies survivable protection technologies for double-link failures. For backup resource sharing issue, the concept of "resource contention" is proposed for the first time, which extends traditional resource sharing strategy from a "static" issue to a "dynamic" issue. The resource contention mechanism increases the network resource sharing potential, and impoves the network resource utilization and blocking probability performance. According to the research, a survivable protection algorithm is proposed for double-link failures, i.e., Resource Contention based Shared Path Protection (RCSPP). In Chapter3, the author studies survivable protection technologies for double-node failures. Aiming at the function defect of traditional protection technologies for double-node failures, the author proposes a node-disjoint based survivable protection algorithm, named Shared Path and Segment Protection (SPSP). SPSP provides primary backup path by segment protection method, which can control the average recovery time of service; provides second backup path by path protection method, which can guarantee the reliability of service recovery; and solves the "Trap" problem, which can reduce the service blocking probability. For surviving double-node failures, SPSP can achieve visible flexibility and scalability with respect to traditional protection technologies.In Chapter4, the author studies survivable protection technologies for translucent optical networks. For optimizing resource utilization under transmission impairment constraint, the author, for the first time, proposes a sharing constraint relaxation strategy for both regenerator and wavelength resources, which can expand the network resource sharing capacity and improve network resource efficiency. Based on this relaxation strategy, a survivable protection algorithm is proposed for translucent optical networks, i.e., Impairment aware Sharing constraint Relaxed Path Protection (ISRPP). In Chapter5, the author studies survivable protection technologies for energy-efficient optical networks. In order to solve the contradiction between power efficiency and resource efficiency for network energy saving, the author proposes a power-aware energy saving strategy. By using fiber cost in the process of both sevice connection establishment and releasement, this strategy separates the working paths and backup paths by different fibers as far as possible, which can enhance the network resource efficiency and reduce the network resource cost for energy saving. Based on this strategy, a survivable protection algorithm is proposed for energy-efficient optical networks, i.e., Power Aware Shared Path Protection (PASPP).In order to validate and evaluate the performance of survivable protection algorithms proposed in this dissertation, the author develops the corresponding simulation platform software, which is presented in chapter6with overall framework, module structure, and partial pseudo codes. In chapter7, the author concludes the dissertation and looks to the future research work.