Architecture for SDN-Independent Gateway

SDN is a centralized network where one SDN controller manages the entire network. Due to the centralized nature of SDN, the broad DATA-Plane range cannot simultaneously send control messages to SDN OVS(Open vSwitch), the farthest from SDN-Controller. Therefore, SDN has a limited range of DATA PLANE depending on the performance of the SDN controller. To solve the problem of scalability, there is a way to extend the DATA-Plane range by connecting several existing SDN controllers to one SDN controller. The method of connecting several SDN controllers is called an SDN-cluster. In addition, ONOS(Open Network Operating System)-Atomix, a form in which SDN controllers share information by storing information of multiple SDN controllers in one server, is also proposed. In this paper, we propose Independent Gateway (IGW). IGW suggests that the SDN controller can operate independently, such as ONOS-ATOMIX, while the amount of control messages is less than SDN-clusters and ONOS-ATOMIX.