Abstract: Current research on controller deployment in software-defined network(SDN) mainly focuses on latency optimal of the controlling messages routing. The betweenness centrality was introduced as a factor to the controller deployment problem and the importance of betweenness centrality in controller deployment location was analyzed. Then a multi-factor node ranking scheme(MFRS) was proposed, the betweenness and the reliability are chosen for the node ranking factors. The nodes are layered and the controlling weight of each node was calculated according to the connecting relations of the nodes in different layers. The location of the controller was determined finally. Simulation shows that the hops of the controlling messages routing under MFRS is less than under the latency aware shortest path scheme, and the reliability of MFRS is higher than it of the latency aware shortest path scheme.

Key words: software-defined network, controller deployment location, betweenness centrality, multi-factor node ranking