Juniper Networks M5 - Manual (Page 144)

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
124 M5 and M10 Internet Routers Hardware Guide