In Software Defined Networking (SDN), the network management is logically centralized but physically distributed among the controllers to improve the scalability compared with a completely centralized model. As an alternative to managing the network state in SDN in a distributed way, this work proposes a distributed protocol called SDN Resource Discovery Protocol (SDN-RDP). This protocol divides and distributes the network management among the controllers.
In essence, each controller discovers a portion of the network topology creating a minimum-latency tree rooted at each controller, thus creating the control layer. Through the delay-constrained shortest paths, henceforth called control channels, the controllers collect network state information from nodes, and decide and distribute the forwarding decisions to them. This process is asynchronous since there is no global initialization process to activate the execution of the protocol, and knowledge about the network is not required. Simulation results show that the proposed protocol works efficiently on large networks in terms of time and load.