Research On Controller Placement Algorithms Based On Reliability Optimization In SDN

In the traditional network, the tight coupling between the controlling panel and the switching panel has brought out lots of issues in the aspects of cost, intelligence, manageability and flexibility, the old network framework could not bear the demands from the company, operation business as well as the common internet user nowadays. In recent years, the rising network architecture Software Defined Network (SDN) becomes the typical one which can realize the programmable network. It can solve the old network architecture problems and becomes the hot issues in the information industry. As there are more and more Software Defined Network frameworks deployed in the large-scale network topology, the deployment schemes in the single-controller mode cannot meet the actual demands, Distributed deployment schemes in the multi-controller mode, which separates different controllers into different control fields, is an efficient way to the scalability of the control panel.In this scheme, how to locate the controller and which switches one specific control:field can manage, that is the controller placement problems, need to be seriously considered for the given network topology. When considering the placement schemes of the controllers, the reliability of the communication between the controller and switches is a significant, factor. Therefore, it is of great significance to study the controller placement schemes for optimizing the network reliability. Based on the target of optimizing the average reliability of the network, this paper considers the shortest path as well as the multi-path between the controller and switch, and raises up two model for controller placement respectively. When considering the single path scenario, this article comes up with the clustering-based and greedy-based controller location algorithms, which respectively can achieve the global and local reliability optimization. Afterwards, the two algorithms are extended to the multi-path scenario. And a concept of Reliability Factor"(RF) to approximate the actual reliability is also proposed in this article which can help optimize the reliability of the network accompanied with the two algorithms. Finally, this article evaluates the two controller placement algorithms over the Internet Topology Zoo and OS3E, comparing with the random algorithms to validate their performance.