Chapter 6 Deploying Wireless Networks for FortiOS 5.0 : Wireless Mesh : Configuring a meshed WiFi network : Viewing the status of the mesh network
  
Viewing the status of the mesh network
Go to WiFi Controller > Managed Access Points > Managed FortiAP to view the list of APs. The Connected Via field shows Mesh for mesh-connected units and lists the IP address to which they connect.
In the FortiAP CLI, you can check the main ip field in the output from the command
cw_diag -c mesh