OpenConfig and OpenROADM Automation of Operational Modes in Disaggregated Optical Networks

Abstract

OpenConfig and OpenROADM are emerging as the most relevant initiatives to support partial disaggregation, in which the optical line system is provided by a single vendor while transponders can be provided, in pairs, by different vendors. This way, vendor lock-in is eliminated at the transponder level, without significantly impacting the transmission performance. Although the above initiatives have defined YANG models reaching a good level of maturity, there are still open issues that prevent the full deployment of vendor-neutral partially disaggregated solutions. Among these, the candidate transmission modes in a transponder, including proprietary solutions, are exposed in the YANG models as opaque attributes called Operational (OP) Modes, thus limiting the awareness and the effectiveness of the SDN controller in the selection of the most appropriate transmission mode. In this work, we focus on the open issues related to the configuration and adaptation of transmission parameters. In particular, we focus on the OpenConfig concept of OP Mode enabling the abstraction of transmission complexity but currently preventing an SDN controller to manage transponders in a fully vendor-neutral way. This work first estimates, through a simulative study, the network performance benefit that is achievable by optimizing the OP mode selection. Then, a telemetry-based automated solution is proposed, designed and implemented to enhance the OP mode concept in case of both provisioning and adaptation scenarios (e.g., upon failure), also considering the impact in the tributary/client network. In particular, the following components have been designed and implemented: (i) software agent for OpenConfig transponders; (ii) software agent for OpenROADM line systems, (iii) an automatic telemetryassisted monitoring handler; and (iv) SDN control procedures implemented in the ONOS Controller. The proposed components and comprehensive solution have been evaluated in a network testbed encompassing multi-vendor network elements, successfully demonstrating a full vendor-neutral partially disaggregated provisioning and recovery operations.

Experimental Demonstration of Extended 5G Digital Fronthaul Over a Partially-Disaggregated WDM/SDM Network

“…This value is well below the 90 min specified by the 5G infrastructure public private partnership [34]. Also, the results obtained are in the order of those found in [35], [36] (also excluding eventual offline DSP) which are based on Open-Config/OpenROADM interfaces. Please note that fronthaul is a service whose requirements are quite stable over time and network reconfiguration is not frequent.…”

Coordinating Pluggable Transceiver Control in SONiC-based Disaggregated Packet-Optical Networks

“…In large metro networks, a single controller with visibility on both packet and optical resources is hardly implementable due to scalability issues. Two controllers are then typically considered: an Optical SDN Controller (OptC) in charge of the the disaggregated optical transport network (e.g., adopting ODTN solutions for the support of OpenROADM and OpenConfig models [4]) and a Packet Controller (PckC) supporting Layer 2-7 configurations. Traditionally, each SDN controller has full visibility on all components and software modules of every controlled network element.…”

“…The latter is designed for full disaggregation where both transponders and reconfigurable optical add drop multiplexers (ROADMs) are controlled in a vendor neutral way. Both define YANG models for NETCONF-based SDN agent implementations [4]. Considerable work on disaggregation is also ongoing in the telecom infra-project (TIP) and in the Open Disaggregated Transport Network (ODTN) initiatives [5].…”

“…For example, a single packet switch can provide both intra-data center (DC) traffic aggregation and, thanks to coherent pluggables, effective DC-to-DC interconnection. However, controlling packet-optical solutions requires a complete operating system that is much more complex than traditional NETCONF/YANG software agents employed in standalone transponders [4,5]. SONiC (Software for Open Networking in the Cloud) is an open-source network operating system already deployed in production intra-DC networks and it is also considered a strong candidate to control packet-optical nodes although some operational extensions are needed to fill the existing architectural gaps.…”

A Scalable Telemetry Framework for Zero Touch Optical Network Management

“…The work in [32] exploits a telemetry-based workflow to assign the proper transmission operational modes to transponders (including proprietary modes not disclosed explicitly to the SDN controller) during connection provisioning in partial disaggregation. The work evaluates also the impact of the proposed telemetry workflow in a multi-layer network upon soft failure recovery, affecting both the optical and the packet switched layer.…”