Low interruption ratio link fault recovery scheme for data plane in software-defined networks

Link backup is an important factor in the fault tolerance of SDN. The current research directions are proactive schemes and reactive schemes. The proactive schemes deploy the backup flow rules in the switches in advance and reserve the backup bandwidth. In reactive schemes, the controller calculates the backup path when a failure occurs. The proactive scheme easily causes the switch and link bandwidth resources to be exhausted, while the recovery time of the reactive scheme is too long. Moreover, none of the current methods considers the flow interruption rate. This article designs a set of efficient and low interruption rate link backup scheme. Our objective is to reduce the number of interrupted flows due to link failures. With this objective, we formalize the selection of the backup paths as an integer programming problem, and prove that it is NP-hard. Then we design a heuristic algorithm to solve it. We propose two algorithms to further optimize the calculated backup paths to reduce the need for backup flow rules and backup bandwidth. Simulations show that our method can effectively reduce the flow interruption rate after link failure recovery, and only needs less network resources.