Zoning for hierarchical network optimization in software defined networks

Software defined networking (SDN) decouples control plane functionality from the data plane and features the presence of programmable dumb network devices, which have no or little intelligence and take control commands from a central controller at the control plane. The central controller is responsible for controlling data plane hardware and optimizing network operation. Centralized network optimization and control is impractical or infeasible when the network becomes too large in size or loading. Distributed network optimization comes into play under this circumstance. Fully distributed network optimization requires local intelligence at individual network elements, against the basic concept of SDN. In this paper we consider SDN-friendly zone-based distributed network optimization and studies the integral network zoning problem, that is, how to group network elements into zones such as to minimize the overhead of distributed network optimization. We give a mathematical formulation of the problem and show that it is NP complete. We then present three heuristic solutions and evaluate their performance through simulation.