Chassis-Application Monitoring
Chassis-application health monitoring is always enabled. The Firepower 4100/9300 chassis supervisor checks the threat defense application periodically (every second). If the threat defense device is up and cannot communicate with the Firepower 4100/9300 chassis supervisor for 3 seconds, the threat defense device generates a syslog message and leaves the cluster.
If the Firepower 4100/9300 chassis supervisor cannot communicate with the application after 45 seconds, it reloads the threat defense device. If the threat defense device cannot communicate with the supervisor, it removes itself from the cluster.