Corybantic: towards the modular composition of SDN control programs

Software-Defined Networking (SDN) promises to enable vigorous innovation, through separation of the control plane from the data plane, and to enable novel forms of network management, through a controller that uses a global view to make globally-valid decisions. The design of SDN controllers creates novel challenges; much previous work has focused on making them scalable, reliable, and efficient. However, prior work has ignored the problem that multiple controller functions may be competing for resources (e.g., link bandwidth or switch table slots). Our Corybantic design supports modular composition of independent controller modules, which manage different aspects of the network while competing for resources. Each module tries to optimize one or more objective functions; we address the challenge of how to coordinate between these modules to maximize the overall value delivered by the controllers' decisions, while still achieving modularity.