SDN is a new network paradigm which has been deployed in many network scenarios. As the development of SDN, the scale of SDN is extending. However, due to the the limit scalability of centralized control plane, scale of SDN is restricted. Existing solutions can be separated into two main classes: deploying distributed controllers and synchronizing states via East-West interface. However, due to the private design of interface of distributed controller, they can not coexist with each other.Moreover, the existing East-West interfaces are not efficient for network environment with insufficient link capabilities like Ad-Hoc network.To solve this problem, the Open eXchange Protocol (OXP) is proposed. OXP is an efficient protocol for scaling SDN, which supports heterogeneous controllers to cooperate with each other. OXP provides Network abstract mechanism to reduce the cost of information synchronization significantly. Also, OXP provides two working modes:simple and advanced models and two information exchanging modes:compressed and normal models to meet diverse networks' requirements.Particularly, the compressed mode, which reduces the cost of communication significantly, is designed for networks with insufficient link capabilities like Ad Hoc network. |