A Hierarchical K-Means Algorithm for Controller Placement in SDN-Based WAN Architecture

As a novel network architecture, Software Defined Networking (SDN) has been drawing more and more attention. SDN decouples the controller logic from the data plane and it enables the network programmability. Generally in the local area networks (LANs), single controller is sufficient to control the whole network. However the scale of wide area networks (WANs) is always large. Taking into account the latency and reliability, it is necessary to deploy multiple controllers in WANs. Controller placement problem is one of the most important issues in SDN with multiple controllers. In this paper, we propose an algorithm based hierarchical K-means algorithm to solve controller placement problem. In addition, we partition the large network into several single controller SDN domains by our algorithm. To evaluate the effective of our algorithm, we do the experiments in the Internet2 OS3E topology. Experimental results show the partition by our algorithm is more balanced than the optimized K-means algorithm.