| Optical-fiber technologies employing wavelength-division multiplexing (WDM) are currently being researched and commercially deployed to satisfy our increasing bandwidth requirements because, by using WDM technologies, an optical fiber can support multiple non-overlapping wavelength channels, each of which typically operates at the data rate of 10 Gbps or 40 Gbps. In such a network, the failure of a network element, e.g., a fiber, can cause the failure of several wavelength channels, thereby leading to large data and revenue loss. The development of fault-management software, projected to grow significantly in the years ahead, is a top priority for both carriers and vendors. This dissertation investigates the performance and design issues of survivable optical networks against failures.; This dissertation first explores the problem of dynamic shared-path protection, which is desirably resource efficient because of backup sharing. It proves the NP-completeness of the problem, develops a heuristic to compute a feasible solution with high probability, and designs another heuristic to optimize resource consumption for a given solution.; As protection-switching time, resource efficiency, and scalability are primary concerns of a protection scheme, this dissertation proceeds to propose sub-path protection, which achieves high scalability and fast recovery time for a modest sacrifice in resource utilization.; While the transmission rate of a wavelength channel is high (typically STS-192 or STS-768), the bandwidth requirement of a typical connection request can vary from the full wavelength capacity down to STS-1 or lower. Different low-speed connections may request different bandwidth granularities as well as different protection schemes (dedicated, shared, or no protection). How to efficiently groom such low-speed connections while satisfying their protection requirements is investigated next. Both protect ion-at-lightpath level and protection-at-connection level are examined and evaluated.; Next-generation SONET/SDH technologies enable network operators to provide integrated data and voice services over their legacy SONET/SDH infrastructure to generate new revenue. An important open research problem on data over SONET/SDH (DoS) is survivability: SONET automatic protection switching is too resource inefficient for data services, and the protection mechanisms of data networks are too slow for mission-critical applications. This dissertation proposes two approaches for provisioning survivable DoS connections. The approaches exploit the tradeoff between resource overbuild and fault-recovery time while utilizing the inverse-multiplexing capability of virtual concatenation to increase backup sharing. |
