Efficient Switch Migration for Controller Load Balancing in Software Defined Networking : (Invited Paper)

The number of multi-controller datacenters is in- creasing with the increasing size of software-defined networking (SDN) datacenters. The performance of an SDN datacenter depends largely on the delay of response from the controller. The delay of response depends on the controller load and the distance from the SDN switch. The load of a controller depends on the number of requests it receives from the switches it controls. Therefore, a good switch-controller assignment is very important for load balancing the controller and the performance of an SDN datacenter. In this paper, we consider multiple controllers and formulate problems for initial and incremental load balancing. The initial assignment process is executed at the beginning of the network deployment. After initial deployment, the incremental assignment process is executed periodically. The incremental process migrates some of the switches to another controller to improve the performance of the network. We propose greedy and clustering-based solutions for initial switch-controller assignment. We also propose a greedy solution for incremental assignment. Our proposed solutions are evaluated using both synthetic and real datasets, and the parameters are driven by experiments at a data center.