Controller Cluster-Based Interconnecting for Multi-domain SDN Networks

In order to exchange information and have a coordinated control for software defined network (SDN), this paper proposes a controller cluster-based interconnecting framework based on load balancing, which can be implemented through two levels of controller coordination, i.e., inter-cluster and intra-cluster interconnection. Specifically, inter-cluster interconnection is implemented by migrating the controller of a cluster with the lightest load to another cluster with plenty of cross-domain flow tables. When a switch receives the most amount of flow tables, intra-cluster interconnection can switch its primary and secondary controller within a cluster. This framework alleviates the load pressure of controller while being able to exchange control information between different SDN controller domains, and it improves quality of service of SDN controllers as well.