A Scalable and Robust OpenFlow Channel for Software Defined Wireless Access Networks

In recent years, there has been an increasing number of Software Defined Wireless Access Network (SDWAN) proposals aiming to cope with the proliferation of mobile devices, as well as, the novel Quality of Service (QoS) demands. One of the most important issues in the SDWANs is to maintain a scalable and robust OpenFlow channel through which the network control and update information (i.e., OpenFlow traffic) are exchanged. However, the standard channel does not well support those characteristics nor does it properly conform to the SDWAN environment. This paper seeks to remedy these problems by analyzing the requirements of SDWAN's OpenFlow channel. We then propose a novel OpenFlow channel named mOpenFlow, which is not only compatible with the SDWANs but also evolved with the OpenFlow standard. The advantage of mOpenFlow is using multipath communication for conveying OpenFlow traffic. Hence, both the robustness and the achievable throughput of the OpenFlow channel is significantly enhanced (i.e., scalable). Combining with the compatibility requirement, the multipath TCP is adopted in the mOpenFlow's design. We extensively evaluate the channel's performance in SDWANs including emulated SDN devices and a real controller. The results show that mOpenFlow outperforms the standard channel both in terms of robustness and scalability.