Research On Key Technologies Of North-Facing Controller In SDN

With the development of Internet technology, especially driven by data centers, cloud computing and mobile Internet technology, the needs of users have become more complex, business have been updated more frequently, and the traditional Internet architecture has become increasingly unsuitable for the needs. The concept of SDN (Software-Defined Networking) is based on separating control plane from forwarding plane of the network devices and constructing a unified control plane instead. Undoubtedly, SDN has become a key technology of solving existing problems and building the next generation of Internet technology. Controller, as the core component of SDN, is a bridge between the application layer and the data forwarding layer. The implementation methods and improvement of the controller have a significant impact on the development of SDN technology. OpenFlow is the standard protocol for the controller to support in the south bound. Unlikely, there is no unified conclusion for the implementation of north-facing support technology in the controller. So, following the path of industry and academic research, I mainly finished the following work in the paper:Firstly, through the study of the logical structure of SDN, the underlying OpenFlow switches specification and OpenFlow protocol, a full picture of the entire SDN network architecture has been drawn.Secondly, I studied and analyzed the architecture, functional modules and the internal implementation of a SDN controller, combined with the open-source controller named Floodlight. The work helped lay a solid foundation for the further realization of north-facing technological innovation in the controller.Thirdly, through the analysis of needs from the application layer and the restrictions of north-bound interface implemented by REST API in the current controllers, I proposed OpenNML(Open Network Model-driven Language), which is a business modeling language specifically defined for SDN, as the north-facing support technology solution in the controller.Fourthly, under the guidance of the previous research results, I did secondary development on the Floodlight controller, designing and implementing a SDN controller based on OpenNML language. The controller is different from the current controllers, which provide specific API to meet specific business needs, but provides a versatile and flexible way for users of different application scenarios to build the business model in a unified way. The work will promote the north-facing standardization process of SDN controller. Finally, I designed a prototype system and conducted experiments to verify the functions of the controller instance named Prislight.The result shows that the controller has feasibility and practical applicability.