SDN link fault network convergence method based on sub-topology network

The invention discloses an SDN link fault network convergence method based on a sub-topology network, and the method comprises the steps: planning a sub-topology network embedded in a network topology through employing the remaining link bandwidth of a current network after an SDN controller obtains network global information and a fault, wherein the sub-topology network is composed of a plurality of hub nodes and paths among the hub nodes, and non-hub node enters and exits the sub-topology network through the attached hub nodes. According to the method, the sub-topology network used for fault convergence is established, synchronous convergence operation of multiple flows is supported, the network topology size of the operation is reduced, the number of added and deleted flow tables is effectively reduced, meanwhile, the quality of a transfer path can be guaranteed, and the convergence time is shortened. The link fault recovery method is provided under the condition that the advantages of the SDN and the sub-