Wireless Mesh Networks (WMNs) are vulnerable to various security threats because of their special infrastructure and communication mode,wherein insider attacks are the most challenging issue.To address this problem and protect innocent users from malicious attacks,it is important to encourage cooperation and deter malicious behaviors.Reputation systems constitute a major category of techniques used for managing trust in distributed networks,and they are effective in characterizing and quantifying a nodes behavior for WMNs.However,conventional layered reputation mechanisms ignore several key factors of reputation in other layers;therefore,they cannot provide optimal performance and accurate malicious node identification and isolation for WMNs.In this paper,we propose a novel dynamic reputation mechanism,SLCRM,which couples reputation systems with a cross-layer design and node-security-rating classification techniques to dynamically detect and restrict insider attacks.Simulation results show that in terms of network throughput,packet delivery ratio,malicious nodes identification,and success rates,SLCRM implements security protection against insider attacks in a more dynamic,effective,and efficient manner than the subjective logic and uncertainty-based reputation model and the familiarity-based reputation model.