Hybrid SDN architecture to integrate with legacy control and management plane: An experiences-based study

The application of SDN and OpenFlow in a production network will face the challenges of integration with legacy routers and legacy control and management protocols. Our contribution is to preserve distributed basic functions in legacy network devices and improve central control on complex functions with OpenFlow. This paper describes a refactoring process of an intra-AS source address validation from a traditional network application to an OpenFlow-based one. It shows practical solutions about introducing OpenFlow into a commercial router by fireware updating without device hardware modification, extending OpenFlow for routing notification and packets sampling to integrate with legacy control protocols, extending an OpenFlow controller to receive and forward routing status and packets sampling messages for external control.