| Software Defined Network(SDN) is an original kind of network architecture in recent years. The control plane decouples from data plane and its programming interface is open and software-defined,which greatly improves the flexibility of business deployment and network control and optimizes the resource utilization.The southbound interface between control layer and forward layer is one of the most important components in SDN architecture. The control layer obtains all the characteristics and schedules the network resource from data plane, by which means bringing down the complexity of the management in network architecture design.Currently, the most famous southbound interface protocol is the OpenFlow. As an open protocol, OpenFlow is expected to break through the interface barriers of the traditional network equipment manufacturers of equipment capacity, and solve the problem of sending required flow table to the data plane layer.However, OpenFlow is designed to meet the requirements of some network instead of characteristics of other network at the earliest.Extending OpenFlow to realize convergence among the different networks is necessary to meet the challenge in converged network.This paper aims to do some research about SDN southbound interface and OpenFlow extension. The main work we have done is as below.(1) Combined with OpenFlow technology, we establish an OpenFlow extension model, which studies the port attributes and flow match fields extension. Besides, OpenFlow extension messages structure is abstracted based on experimenter and flow match message.Then application examples are talked about to discuss the necessity of software defined optical network(SDON).(2) According to the OpenFlow extension model, scheme of software defined optical networks based on OpenFlow agent is proposed and implemented. OpenFlow protocol extension for optical network is realized on southbound interface and concrete researches on extending details are illustrated.(3) Based on our experimental platform, functional verification and analysis of the scheme and implementation are evaluated. |
