Monitoring-cycle based fault detection and localization in mesh all-optical networks

The fault detection and localization (FDL) problem for mesh all-optical networks (AON) is the vital part of the survivability of such networks. This thesis proposes and verifies a novel FDL approach based on monitoring-cycles (m-cycles), which are defined as cycles in an AON with the assigned network monitors and supervisory channels. An m-cycle based fault localization algorithm is developed together with a group of newly defined evaluation metrics: the fault localization degree, wavelength overhead, and cost reduction. Three m-cycle construction algorithms are developed and evaluated: the heuristic depth first searching, the shortest-path Eulerian matching, and the heuristic spanning-tree algorithms. The results obtained by applying these algorithms to some typical networks show that the m-cycle based FDL approach is effective and cost-efficient for mesh AONs.; It is also proven in this thesis that the complete fault localization is achievable if and only if an AON contains neither degree-2 nor extended degree-2 chains. Furthermore, it is proven that the spanning-tree based m-cycle construction algorithm can produce an m-cycle set to implement the complete fault localization.; To minimize the wavelength overhead and localization degree, and to consider the limitation of lightpath length in real AONs, the m-cycle construction is formulated as a variant version of constrained cycle-cover problem. A novel branch-and-bound (B&B) based two-phase algorithm is then developed to solve such problems. The analysis of the B&B algorithm shows that feasible solutions are guaranteed and near-optimal solutions are achievable. The good performance of the algorithm is shown in simulation results obtained from typical network examples both in the real world and randomly generated.; Finally, the implementation of m-cycle based FDL approaches is discussed based on the simple network management protocol (SNMP), together with the transmission of alarms and notification in control channels within the control plane of an AON.