Research On SDN In Wireless Local Area Roaming Networks

With the rapid development of smart phones and mobile devices, the innovation of WLAN (Wireless Local Area Network) has attracted much attention, because of the confronted challenges of high handoff frequency, access complexity and network solidification. Meanwhile, a new form of network structure, i.e. software-defined network (SDN), has been emerging. Within the SDN architecture, the control and data planes are decoupled, management is centralized, and application-oriented programmability is enabled.This thesis first describes the fundamental theory, the key techniques and the main application scenarios of WLAN and SDN. After that, we analyze the current research status and trends on the combination of SDN and WLAN.In this thesis, the main topic is to design an SDN-based roaming WLAN in layer2and3. Specifically, in the layer2roaming network, we convert conventional802.11frames into Ethernet frame and use OpenFlow to control the flows at a very granular level, so that we can realise layer2seamless roaming with insensibility of STA. Moreover, we develop a physical platform and test the performance of our proposed architecture.Furthermore, in the layer3roaming network, we use OpenFlow to build dynamically programmed VLAN network and optimize the Inter-VLANs communication mechanism. Therefore, the new network can improve its latency and throughput. We also build a virtual network via Mininet and verify our proposal.In the end, this thesis points out the future works of this topic, as well as the potential research and application areas of the combination of SDN and WLAN.