OFMon: OpenFlow monitoring system in ONOS controllers

Since the concept of Software Defined Networking (SDN) was suggested, many SDN controllers have been proposed. In an early design of SDN controller, single SDN controller should manage a large-scale network. Although the SDN controller has innumerous advantages in the large-scale network, early SDN controllers have suffered from a bottleneck problem in the control plane. To mitigate the bottleneck problem, a concept of distributed SDN controller has been recently proposed such as Open Network Operating System (ONOS). Even if ONOS provides a way to distribute the control plane workload to resolve the bottleneck problem, it has still problems to determine when and how to distribute the control plane workload due to the lack of performance assessment which ONOS provides. In this paper, we propose OFMon to monitor all OpenFlow messages between ONOS controllers and OpenFlow switches. To the best of our knowledge, OFMon is the first OpenFlow monitoring system in ONOS. To evaluate the performance of OFMon in terms of CPU and memory usage, we conduct experiments within a well-controlled environment. As a result, OFMon requires more CPU usage at the maximum of 4% and memory usage up to 6%.