Research On Agile Flow Forwarding Of SDN/Openflow Networks

Software-Defined Networking (SDN) is a radical innovative computer networking architecture, which redesigns the computer network in a clean-slate way and is the biggest technological advance over the past few decades. SDN decouples network intelligence from network forwarding devices, and the network is divided into two planes:the control plane and data plane. All the networking intelligence is logically centralized in the control plane, while data plane is only responsible for packets switching and forwarding according to instructions of the control plane. Moreover, SDN could be directly programmable, we could totally control behaviors of all the network forwarding devices through programming on a logically centralized equipment.OpenFlow is the original implementation of SDN networks, and has already been the de facto standard approach to realize SDN, gained a wide support from the networking industry and academia. But in the original OpenFlow networks, flow forwarding is based on Iayer2to Iayer4header information of packets, which is similar to the way on the traditional TCP/IP networks. Application awareness capability is absent from the OpenFlow network. As a result. Quality of Service (QoS) can not be guaranteed in the OpenFlow network.We add this capability in the standard OpenFlow networks, so the network could differentiate flows of diverse applications based on flows features other than packets’header information, and further obtain flows’requirements, such as bandwidth, delay, jitter, etc. We take advantage of programmability and dynamic forwarding to make real-time agile forwarding decisions for applications flows which are QoS sensitive, which is based on the global network view selecting a light-loaded link rather than resource reservation, so as to improve their QoS and network intelligence, as well as to balance links’loads.In our paper, we firstly introduce SDN and OpenFlow networks. We also discuss working principles, characteristics, benefits and deficiencies of packets forwarding both in the traditional TCP/IP networks and SDN networks. Secondly, we discuss the state-of-art studies and proposals on SDN networks, and how we build our SDN testbed. After that, we give our proposals on how to forward flows agilely in the SDN networks based on OpenFlow protocol, describe the whole system and detail each parts of the system. Finally, we make a conclusion on our paper, and point out the accomplishments and existing problems. We also show directions of the further research.