A Novel Hybrid Routing Forwarding Algorithm in SDN Enabled Wireless Mesh Networks

As an essential part of next generation Internet, Wireless Mesh Networks (WMNs) have attracted much research attention due to its potential advantages including low up-front cost, ease of deployment, enhanced capacity and service coverage. However, the inherit features of wireless multi-hop networks have put forward a severe challenge for traffic engineering problem. Conventional traffic engineering techniques either locally manipulate network traffic or adopt unreliable best-effort delivery mechanism. Software Defined Networking (SDN) is a new networking paradigm that separates the network control plane from the packet forwarding plane and provides applications with an abstracted centralized view of the distributed network state. A logically centralized controller that has a global network view is responsible for all the control decisions and it communicates with the network-wide distributed forwarding elements via standardized interfaces. Considering the current price of SDN equipments and deployment cost, this paper proposes an idea that gradually increases the number of SDN forwarding element in the networks. In other words, partly deployment of the SDN forwarding element in the networks can achieve fast forwarding traffic. On this basis, a new traffic engineering algorithms named Hybrid Routing Forwarding Algorithm (HRFA) which is based on SDN forwarding and OSPF (Open Shortest Path First) protocol is designed. This hybrid routing scheme divides the network nodes into conventional nodes and SDN forwarding elements (SDN-FE), and chooses effective forwarding strategies for different network elements, which will improve the overall performance of the networks. In order to verify the performance of the proposed algorithms, a number of simulation experiments are carried out in the NS-2 simulation platform. The results show that compared with the traditional routing forwarding method, HRFA can well increase the normalized throughput, and reduce the delay and packet loss.