An Enhanced Message Distribution Mechanism for Northbound Interfaces in the SDN Environment

Software-Defined Network (SDN), which is recommended as a new generation of the network, a substitute for TCP/IP network, has the characteristics of separation of data plane and control plane. Although the separation of the control plane brings a high degree of freedom and simple operation and maintenance, it also increases the cost of north–south communication. There are many additional modules for SDN to modify and enhance the basic functions of SDN. This paper proposes a message queue-based northbound communication mechanism, which pre-categorizes messages from the data plane and accurately pushes them to the apps potentially interested. This mechanism improves the efficiency of northbound communication and apps’ execution. Furthermore, it supports both OpenFlow and the protocol-independent southbound interface, and it has strong compatibility. Experiments have proved that this mechanism can reduce the control-response latency by up to 41% when compared with the normal controller northbound communication system, and it also improves the network situation of the data plane, such as real-time bandwidth.