# Monitoring Temperatures of Modules

You can view the temperature of each module by issuing the show environment all and show environment table commands. In addition, the system generates detailed log messages if the temperature of a module is outside normal operating limits.

For example, if the temperature of any forwarding controller exceeds 212°F (100°C), a message appears on the console and the event is added to the system log. If you receive this message, report it to your customer service representative.

If the temperature of any module exceeds the upper temperature limit, the system immediately goes into thermal protection mode. After the system has entered thermal protection mode, you must resolve the cause of the high temperature quickly.

Table 13: Troubleshooting High-Temperature Conditions

Cause of High Operating Temperature | Symptoms | Resolution
--- | --- | ---
Air vents to system are blocked | Space around system does not meet specifications. (See System Specifications.) | Increase space around system.
Ambient temperature exceeds specifications | Ambient temperature exceeds specifications. (See System Specifications.) | Provide extra cooling or heating in the room where the system is located.
One or more cooling fans have failed | FAN OK LED (FO) on SRP module is not illuminated. FAN FAIL LED (FF) on SRP module is illuminated. | Replace fan tray. (See Maintaining the Router.)
A module fails | FAIL LED on module is illuminated. | Replace module. (See Installing Modules.)

When you have resolved the cause of the high temperature, the system automatically resumes operation. For example, if the system entered thermal protection mode and you replaced the fan tray, a chassis reboot is not required. The system automatically restores power to the LM and SFM modules.