Abstract

In this thesis, we are particularly interested in studying the impact of network element failure(s) on network survivability. Namely, we propose and analyze a series of models and schemes to protect and restore the affected services in the networks, thus achieve a better survivability in optical networks. In additions to an introduction of optical networks and a survey of the related work, this thesis first focuses on the problem of fast recovery in Chapter 3. By using the framework of Offset-Time restoration, a novel model based on time-driven scheduling is proposed. It substantially shortens the restoration time and can be applied in both single-link failure and dual-link failure scenarios. Next, capacity reprovisioning, as a simple and efficient mechanism to protect a network against multiple failures, is investigated and a new reprovisioning scheme is proposed in Chapter 4. Finally, the application of capacity reprovisioning in traffic grooming is considered. Two frameworks, i.e., lightpath level reprovisioning and connection level reprovisioning, are proposed in Chapter 5 to improve the survivability of optical networks with grooming capability.