Exploiting Telemetry in Multi-Layer Networks

Next generation networks are evolving towards multi-layer scenario, where packet and optical domains are coupled to provide high dynamicity and high throughput. Regarding the optical domain, the white-box concept (i.e., the disaggregated network approach) is promising to break the vendor lock-in for optical transmission solutions. At the packet domain, since standard OpenFlow-based SDN techniques showed limited functionalities (i.e., missing stateful capabilities pipelining), novel P4-based solutions are emerging as candidate framework, envisaging the dynamicity of the traffic and the hardware programmability paradigm. In this scenario, the telemetry functionality is becoming a promising solution for network monitoring, where data is efficiently streamed from network devices. In fact, in order to meet the service SLA requirements, next generation networks will leverage on advanced monitoring features, based on streaming techniques, allowing the control/management system to detect link failures and avoid traffic congestion. In this paper, we propose an experimental validation of a telemetry-based monitoring system in a multi-layer network. For the optical domain, we rely on an open-source implementation of an OpenConfig NETCONF agent enhanced with telemetry, in order to enable the sample data streaming of a number of key transmission parameters. For the packet layer, we exploit the P4 in-band telemetry, providing information on the end-to-end experienced latency and interfaces throughput. The monitoring system, enhanced with a proper GUI based on Grafana, is able to request the streaming of one or more selected parameter(s), on demand and with proper granularity, from different network domains. The implemented telemetry-based monitoring system has been experimentally validated over a multi-layer network encompassing EON and two P4 aggregation switches, highlighting the main functionalities and the effectiveness of the proposed solution.