Juniper Networks M10, M5 Juniper Networks Technical Assistance Center, Troubleshoot the Fan Tray

Troubleshoot Packet Forwarding Engine Components

Juniper Networks Technical Assistance Center

If you need assistance during troubleshooting, you can contact the Juniper Networks Technical Assistance Center (JTAC) by e-mail or telephone. See “How to Request Support” on page xix.

Troubleshoot the Fan Tray

The fan tray installed along one side of the chassis houses four fans that draw room air into the chassis to maintain an acceptable operating temperature for the Routing Engine, PICs, FEB, and other components. For a graphic depiction of the airflow, see Figure 10.

For the fan tray to function properly, the clearance around the chassis must be sufficient for unobstructed airflow. See “Clearance Requirements for Airflow and Hardware Maintenance” on page 40.

Temperature sensors on the components detect temperatures above the acceptable range. Fan failure or an excessive temperature condition triggers the red alarm LED on the craft interface. If the temperature passes the acceptable maximum, the Routing Engine shuts down the router by turning off the power supplies.

To troubleshoot the fan tray, follow these guidelines:

•Check the status of the fans in the fan tray by issuing the show chassis environment command. The output includes an entry for each fan, as shown in this example:

user@host> show chassis environment

Class Item	Status	Measurement
...
Fans Left Fan 1	OK	Spinning at normal speed
Left Fan 2	OK	Spinning at normal speed
Left Fan 3	OK	Spinning at normal speed
Left Fan 4	OK	Spinning at normal speed
...

For further description of the output from the command, see the JUNOS Internet Software Operational Mode Command Reference: Protocols, Class of Service, Chassis, and Management.

•If the fan tray fails, determine whether you can distinguish individual blades in a fan—this is not possible when the fans are rotating at normal speed.

Troubleshoot Packet Forwarding Engine Components

The following sections describe how to troubleshoot the FEB and PICs:

•

•

Troubleshoot the FEB on page 125

Troubleshoot PICs on page 125

124M5 and M10 Internet Routers Hardware Guide