Multi-Controller Deployment Algorithm in Hierarchical Architecture for SDWAN

A software-defined network (SDN) is a new paradigm that separates control and forwarding. With the growth of SDN deployment scale, the centralized control plane becomes a bottleneck restricting the expansion of SDN networks. To avoid the problem of limited processing power in the wide area network (WAN), we focus on the multi-controller deployment in hierarchical architecture for software-defined WAN (SDWAN). The hierarchical architecture divides the control plane into multiple levels. The root controller has a global view. The domain controller is only responsible for the control in local networks. In this paper, we use the improved Louvain algorithm to discover the hierarchical community structure. Considering the load balancing and request delay in each partition and reliability of the control plane, we formulate the modeling and propose a hierarchical multi-controller deployment algorithm for the scalability of the SDWAN. The simulation results show that compared with the traditional algorithms, the proposed algorithm not only reduces the average request delay to a certain extent and effectively improves the performance of load balancing in each partition, but also efficiently enhances the reliability of the control plane in the SDWAN and achieves the good effect on the execution efficiency.