Multi-metric Routing Protocol for Multi-radio Wireless Mesh Networks

Wireless Mesh Networks (WMNs) are emerging as low-cost technology to build broadband access networks. With the demand for the real-time multimedia applications like voice over IP and video on demand, providing better quality of service (QoS) in WMNs has become as important research issue. To address this, many cross layer routing metrics are proposed in the literature. But the usage of single link quality metric for different types of traffic within the network is insufficient to guarantee fine grained QoS. Towards this, we propose a multi-metric routing protocol which finds the optimal path based on two routing metrics depending on the type of traffic. We use two metrics namely Metric for Interference, Load and Delay (MILD) and Contention Aware Transmission Time (CATT) for TCP and CBR traffic respectively. MILD is throughput optimizing routing metric where as CATT is delay sensitive metric suitable for multimedia traffic. We implemented these metrics in well-known proactive routing protocol Optimized Link State Routing (OLSR) in ns-2.34. The results indicate that the multi-metric protocol perform better in terms of throughput and average end-to-end delay compared to single metric.