Software Defined Networking (SDN) separates the tightly coupled network control and data forwarding functions. During the past years, it has been applied in all kinds of intra-domain networks, such as enterprise networks, data centers and content provider networks. However, it is a big challenge to extend SDN to inter-domain networks. In this paper, we extend the advantage of SDN to an inter-domain network federation to improve the Internet routing flexibility. To achieve this goal, we propose a Multi-dimension Link Vector network view exchange mechanism (MLV) to exchange the fine-grained inter-domain routing information and enable programmable inter-domain routing. MLV can support flexible inter-domain routing control by exchanging multiple fields of the IP header. Based on MLV, innovations in inter-domain routing can be deployed as applications over SDN controllers. In order to validate the MLV design, we analyzed its performance with BGP-derived Internet AS topology. Finally, we implemented a prototype of MLV and tested it on an internationally collaborative inter-domain SDN testbed.

The decoupled architecture and the fine-grained flow-control feature limit the scalability of a flow-based software-defined network (SDN). In order to address this problem, some studies construct a flat control plane architecture; others build a hierarchical control plane architecture to improve the scalability of an SDN. However, the two kinds of structure still have unresolved issues: A flat control plane structure cannot solve the superlinear computational complexity growth of the control plane when the SDN scales to a large size, and the centralized abstracted hierarchical control plane structure brings a path stretch problem. To address these two issues, we propose Orion, a hybrid hierarchical control plane for large-scale networks. Orion can effectively reduce the computational complexity of an SDN control plane by several orders of magnitude. We also design an abstracted hierarchical routing method to solve the path stretch problem. Furthermore, we propose a hierarchical fast reroute method to illustrate how to achieve fast rerouting in the proposed hybrid hierarchical control plane. Orion is implemented to verify the feasibility of the hybrid hierarchical approach. Finally, we verify the effectiveness of Orion from both the theoretical and experimental aspects.

The decoupled architecture and the fine-grained flow control feature of SDN limit the scalability of SDN network. In order to address this problem, some studies construct the flat control plane architecture, other studies build the hierarchical control plane architecture to improve the scalability of SDN. However, the two kinds of structure still have unresolved issues: the flat control plane structure can not solve the super-linear computational complexity growth of the control plane when SDN network scales to large size, the centralized abstracted hierarchical control plane structure brings path stretch problem. To address the two issues, we propose Orion, a hybrid hierarchical control plane for large-scale networks. Orion can effectively reduce the computational complexity growth of SDN control plane from super-linear to linear. Meanwhile, we design an abstracted hierarchical routing method to solve the path stretch problem. Further, Orion is implemented to verify the feasibility of the hybrid hierarchical approach. Finally, we verify the effectiveness of Orion both from the theoretical and experimental aspects.