Minimal monitor activation and fault localization in optical networks

The scheme for efficient, accurate and scalable monitoring and localizing faults is necessary for transparent optical networks. Optical transparency makes the monitoring and localization process difficult in the optical layer as failures in physical layer propagate and subsequently generate multiple alarms throughout the network. Moreover, failures in physical layer could be detected and located in optical layer before they are propagated to the upper layer. So, a fast and scalable monitoring and fault localization scheme are required to offer a secure and resilient network. In this paper we propose a fault management scheme that handles multiple failures in the optical network using wavelength-division multiplexing (WDM) technology. It consists of a two-phase scheme, namely (a) fault detection which detects faults by raising alarms of the monitoring devices and (b) fault localization that subsequently localizes these faults by invoking an algorithm. The latter phase obtains a set of potential faulty nodes (links). Next, we locate the exact position of faulty node (link) by transmitting the signal through it. We demonstrate the performance of this proposed scheme on a 28-node EuroNet.