Control of open and disaggregated transport networks using the Open Network Operating System (ONOS) [Invited]

Use of disaggregated equipment in optical transport networks is emerging as an attractive solution to bring flexibility and break vendor lock-in dependencies. The disaggregation process requires standard protocols and interfaces between the control plane and network equipment. NETCONF has been selected as the standard protocol, and multiple initiatives are currently working on the definition of standard models for each type of data plane device. Different levels of disaggregation of the data plane are under evaluation, and it is still not clear up to which level it will be useful to disaggregate the data plane. The disaggregation of optical networks yielded the development of several controllers based on software-defined networking concepts, providing an environment for creating and deploying networking application on optical networks. Among them, the Open Network Operating System (ONOS) controller features the most active community with the recent establishment of the Open and Disaggregated Transport Network (ODTN) working group, specifically focused on the introduction of required functionality to control and monitor disaggregated transport networks. This paper reports on the state-of-the-art, potentials, and limitations of the ONOS controller applied to disaggregated optical networks with specific focus on the ongoing activities within the ODTN working group. Then, the paper describes a set of experiments performed on a setup including both emulated and real optical devices controlled with ONOS. The performed experiments consider both the establishment of a connectivity service and the recovery of the connectivity in case of failure on the data plane.