Improving the Fault-Tolerance for Controllers' Negotiation Model under Multi-domain SDN Environments

In multi-domain SDN environments, the controllers need to exchange information frequently. In real situation, both controllers and transmission media may be faulty simultaneously. All this faulty components may cause that fault-free controllers getting the wrong information, and the network cannot work well. Hence, in this paper, a fault-tolerance negotiation mechanism has been proposed. Based on the mechanism, all fault-free controllers can efficiently and robustly to get a common score about the information which are needed to be shared by at most four rounds of score exchange phases. Moreover, the time complexity and the space complexity of generating the correct score are O(n
³
) and O(n
³
) respectively, where n presents the number of total controllers.