In a software⁃defined network, a powerful central controller provides a flexible platform for defining network traffic through the use of software. When SDN is used in a large⁃scale network, the logical central controller comprises multiple physical servers, and multiple controllers must act as one to provide transparent control logic to network applications and devices. The challenge is to minimize the cost of network state distribution. To this end, we propose Distributed ZTE Elastic Network Intelligent Controller (D⁃ZENIC), a network⁃control platform that supports distributed deployment and linear scale⁃out. A dedicated component in the D⁃ZENIC controller provides a global view of the network topology as well as the distribution of host information. The evaluation shows that balance complexity with scalability, the network state distribution needs to be strictly classified.
software defined network; OpenFlow; distributed system; scalability; ZENIC