Hierarchical OAM infrastructure for proactive control of SDN-based elastic optical networks

Elastic Optical Networks will drive a high degree of flexibility enabling dynamic configurable lightpaths provisioning and re- optimization due to next generation bandwidth variable transponders and switches. In order to guarantee quality of transmission (QoT), novel Operation Administration and Maintenance (OAM) solutions are necessary with respect to existing standard management protocols. For optical networks, scalable mechanisms providing fast and effective QoT alarm information, including localization and, possibly, forecasting critical events, are needed. The introduction of the Application Based Network Operation (ABNO) architecture is pushing towards a dedicated OAM Handler, in charge of collecting OAM information from the network, performing correlations and triggering control plane reaction. However, serious scalability issues may arise since a centralized element would have to elaborate a potentially huge amount of data. In this paper, a novel hierarchical OAM architecture is proposed, that enables multi- level OAM entities to provide OAM Handler with effective information, obtained by filtering several OAM messages at each layer, so that the overload of OAM Handler is avoided. Moreover, the NETCONF protocol, typically used for SDN- based node configuration purposes, is proposed and utilized as OAM protocol, in order to achieve high degree of convergence and limit the number of utilized protocols. The proposed OAM architecture is implemented and experimentally evaluated in a QoT degradation use case, showing that multi-level localization and local correlation of events allow aggregated, fast and scalable OAM information set provided to the OAM Handler.