Evaluating and comparing the performance of using multiple controllers in software defined networks

In Software Defined Networks (SDN) the control plane is removed to a separate device called the controller. The controller is the most important and main part in SDN architecture and large SDN networks may consist of multiple controllers or controller domains that distribute the network management between them. Because of the controller importance, it has been given a proper attention and many studies have been made to compare, test, and evaluate the performance of the controllers. This paper aims to evaluate and compare the performance of different SDN controllers which are Open Network Operating System (ONOS), OpenDaylight, POX and Ryu, using Two performance tests; the first test includes connecting two controllers of each of the four controllers to linear topology with different number of switches; and the other test includes connecting different number of controllers of each of the four controllers to linear topology with fixed number of switches. Then for these tests, the performance in terms of some Quality of Service (QoS) parameters such as average Round-Trip Time (RTT), throughput, and jitter are measured between the two end hosts in each network. After the evaluation of the performance has been completed, it had been seen that the controllers showed different behaviors, and that POX controller showed more stable and good performance results than other controllers.