EFW: a cross-layer metric for reliable routing in wireless mesh networks with selfish participants

Wireless mesh networks (WMNs) have emerged as a flexible and low-cost network infrastructure, where heterogeneous mesh routers managed by different users collaborate to extend network coverage. Several routing protocols have been proposed to improve the path delivery rate based on enhanced metrics that capture the quality of wireless links. However, these metrics do not take into account that some participants can exhibit selfish behavior by selectively dropping packets sent by other mesh routers in order to prioritize their own traffic and increase their network utilization. This paper proposes a novel routing metric to cope with the problem of selfish behavior (i.e., packet dropping) of mesh routers in a WMN and two further refinements that reduce the network overhead and improve security. Our solutions combine, in a crosslayer fashion, routing-layer observations of forwarding behavior with MAC-layer measures of wireless link quality to select the most reliable and high-performance path. We integrated the proposed metrics with a well-known routing protocol for wireless mesh networks, OLSR, and evaluated it using both the NS2 simulator and the real-life ORBIT wireless testbed. The results show that our cross-layer metric and its refinements accurately capture the paths reliability, even when a high percentage of network nodes misbehave, considerably increasing the WMN performance.