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Optimal Model for Link Failure Foresight Controller Placement in SDN

Since the control plane and data plane of SDN are separated, the controller placement problem (CPP) is an important issue in SDN. For a given controller placement scheme, if a link fails, the control path between the switch and the controller may change, which may cause drastic fluctuations in the control latency. In order to avoid sharp increases in control latency caused by the link failure, we propose a mathematical model for link failure foresight controller placement (LFFCPP) in this paper. The objective of LFFCPP model is to minimize the control latency fluctuation in the case of a link failure. We test the performance of LFFCPP with and without link failure. Simulation results show that LFFCPP performs better than K-center and CRP in the case of a link failure, and closes to K-center in link failure free case. This proves the validity of the LFFCPP model.