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Junos temperature thresholds in SRX devices and the actions taken when it exceeds the threshold



Article ID: KB22153 KB Last Updated: 29 Dec 2011Version: 1.0
This article provides information about the Junos temperature thresholds and required actions, when these thresholds are exceeded.
  •  What does an SRX device do when it reaches a certain temperature?

  • Are there any specific actions that the device takes when it crosses a threshold?
If the temperature of a SRX device increases, it will take certain actions based on the threshold. It is designed to generate SNMP traps for high temperatures and when the temperature continues to rise and reaches a peak, it then automatically shuts down the device.

SRX is designed to automatically generate the SNMP traps when the thresholds are exceeded (However, there is an outstanding bug with this mechanism. This will be addressed in 10.4R9).  Once all the SNMP parameters are configured, the traps are generated at proper thresholds.

The following MIB needs to be configured on the SNMP tool, which is being used to query the temperature thresholds. Chassis MIB (jnx-chassis. mib)

This MIB has the following traps related to temperature:
Trap Name snmp = jnxOverTemperature
TrapOID =
System Logging Severity Level = Critical

Trap Name snmp = jnxTemperatureOK
TrapOID =
System Logging Severity Level = Alert

For more information, refer to the following link:


  • Overtemperature (jnxOverTemperature): This is sent when several fans fail or the room temperature significantly increases. The service impact of this trap depends on the temperature of the router.

    In general, the router increases the speed of the fans when any component exceeds a temperature of 55° C. The fans remain at the higher speed, until the temperature decreases below the threshold.

    In this case, there is no service impact. However, if the temperature exceeds 75° C, the router transmits a warning and automatically shuts down.

    This scenario creates a significant service impact because the shutdown affects additional routers and equipment. This trap is repeated every minute, until the temperature is brought down to normal. To determine the source of the overtemperature problem, you must physically inspect the router to determine whether any fans have failed in the router.

  • Temperature OK (jnxTemperatureOK): This is sent when a chassis component recovers from an overtemperature condition. For more information, refer to the following link:

The image below illustrates the output of show chassis temperature-thresholds:

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