Efficient flow processing-aware controller placement in future wireless networks

Future wireless access networks include a broad variety of applications. Examples for these range from network applications meant to optimize the usage of resources, e.g. Coordinated Multi-Point (CoMP) transmission, over coordinating network mechanisms for Inter-Cell Interference Coordination (ICIC) to virtualized applications to gain flexibility and save hardware costs such as Virtual Network Functions (VNFs). Still, there is one common thread for all these functions: the necessity for data flow processing. Data flow processing imposes many requirements on network resources and a good allocation of the locations for data processing in a network is a challenging task and crucial for network performance. Hence, data flow processing is a significant point to be considered when searching for efficient control architectures for future wireless networks. We propose a flow processing-aware controller placement framework, which introduces data flow processing to the research domain of future wireless network control and enhances the classic Software-Defined Networking (SDN) view of reducing network control to just packet forwarding. We have developed an optimization problem and a heuristic algorithm that verify the practical feasibility of flow processing-aware controller placement. Our evaluations reveal that the heuristic algorithm performs close to optimal, while reducing the runtime by about four orders of magnitude compared to the optimization problem and thus providing acceptable runtime for real-world application.