Traffic-aware compatible controller deployment

Multi-controller architecture(flat or hierarchical) has been proposed for Software Defined Networking(SDN). The placement of these controllers is needed to be considered, as which influences the optimization of network. To optimize network by placing controllers, we develop our controller placement framework to solve this issue, which is compatible for both flat and hierarchical control plane. Our algorithm is evaluated at some topologies and the simulation results show that: in networks with varied traffic, (1) load balance between controllers(domains) is maintained well and (2) fewer inter-domain flows are generated, which helps to eliminate the impact of control state inconsistency.