The tree in the left hand frame of the Topology displays a list of network devices that are managed by FortiNAC, such as switches or routers. In addition to devices that provide network services, FortiNAC can manage pingable devices, such as alarm systems or printers. If FortiNAC cannot contact a device, a red box is displayed around the icon for the device and also around the icon for the Container used to group devices. The red icons in the Topology tree indicate that the device has not responded to periodic pings sent by FortiNAC. However, there are circumstances in which devices are in contact with FortiNAC but due to their configuration, they will not respond to a ping.
If you are using a directory server, it is communicating with FortiNAC via LDAP. The Topology may turn the directory icon red even though the two are communicating. To prevent this, enable ping on the directory server.
Devices that display in both the Host View and the Topology are managed by the Host View. The Host View does not use ping as a method to verify the connection between FortiNAC and the device. The Host View relies on the polling interval of the switch to which each device is connected to determine if the device is still connected and in contact with FortiNAC. In the Topology tree the icons for devices managed in Host View will turn red if the device has not had any activity on the port to which it is connected for some time. This would eventually cause the MAC address of the device to be removed from the forwarding table of the switch. Depending on the device, you may want to manage it only in the Topology. This prevents the icon from turning red indicating that contact with the device has been lost.
See Icons for status icon definitions.