Software-Defined Networks with Satellite Controllers

Control architectures for Software-Defined Networks are characterized by moving previously distributed network state and control functions to a centralized controller instance, leaving network nodes as simple forwarding elements. While functions like path calculation are expected to benefit from the global network view, maintaining detailed network state far from the corresponding infrastructure increases data exchange between controller and network elements, thereby burdening the control network and increasing response times. In this paper the concept of satellite controllers for Software Defined Networks is introduced, which allow to delegate functions with only local or limited scope to the forwarding elements, while maintaining open programmability in line with the SDN paradigm.