Architectures and algorithms for fault management in optical WDM networks

With the maturing of wavelength-division multiplexing (WDM) technology, one single strand of fiber can provide tremendous bandwidth (potentially a few tens of terabits per second) by multiplexing many non-overlapping wavelength channels. In a wavelength-routed WDM network, with the relatively high frequency of network failures, and the tremendous traffic loss a failure may cause, fault management becomes a critical concern in network design and its real-time operation. This dissertation investigates architectures and algorithms for survivable optical networks.; The dissertation first presents a broad overview of the fault-management mechanisms involved in deploying a survivable optical mesh network. Different parameters are presented which can measure the quality of service (QoS) provided by a WDM mesh network to upper protocol layers, such as service availability, service reliability, restoration time, and service restorability. It reviews the concepts, the factors that affect them, and how to improve them.; Next, the dissertation investigates the problem of using optimal path pair as the routes for the primary and backup paths in a WDM network with and without wavelength-conversion capability. It proves that the problem is NP-complete in wavelength-continuous networks.; In order to satisfy a connection's service-availability requirement in a cost-effective manner, we need a systematic mechanism to select a proper protection scheme for each connection request. Connection availability is proposed to use as a metric to provide differentiated protection services. A mathematical model is developed to analyze the availabilities of connections with different protection modes. Integer linear program (ILP) and heuristic approaches are studied to provision the connections cost effectively while satisfying the connections' availability requirements.; To combat the effect of multiple concurrent failures, new backups can be reprovisioned after one failure such that the next potential failure can be handled effectively and efficiently. Backup reprovisioning approaches are proposed and studied under a novel network model.; Optical burst switching (OBS) is a promising technique for supporting high-capacity, bursty data traffic over optical WDM networks. The fault-management issues in an OBS network are studied. A pre-planned global rerouting scheme is proposed to balance network load and a novel fault-tolerant node architecture is proposed to quickly restore the bursts on a failed link.