Switch Migration Scheduling in Distributed SDN Controllers

Due to the dynamic nature of traffic, networks must rapidly adapt to changing conditions. This is especially true in the context of the control plane which must ensure continuous and seamless operation. Switch migration, the process of changing the controller associated with a switch, is an important tool in facilitating this goal. In this work, we study the problem of minimizing the overall time to migrate a set of switches. We examine the problem subject to constraints on controller resources and QoS groups. We show that the problem is NP-hard and provide heuristic algorithms for solving large instances in practice. Through extensive experiments, we demonstrate that the heuristics achieve performance close to optimal while reducing the running time by several orders of magnitude.