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LED Activity

When the system boots, it runs a series of tests for each module installed in the system, and the LEDs display various configurations. See Table 12 and Table 13 to understand normal and abnormal LED activity.

Note: When you reboot the system after installing a new version of the software, the line modules appear to boot twice.

Table 12: Normal Activity of Functional Status LEDs During Booting

OK	FAIL	ONLINE	Status Process
off	off	off	1. Module is in the power-up restart state; the FAIL LED stays on briefly.
off	on	off	2. Module is initializing, and diagnostic tests are running; the FAIL LED stays on briefly.
on	off	off	3. Module passed the diagnostics; the system boots.
on	off	on	4. Module is now up and running.

If the system detects an error during booting, the FAIL LED lights. Some failure conditions can cause the module not to boot. In this case, the LEDs might all be off. The system then resets the module.

If the operational software detects an error, the FAIL LED lights. Some errors can cause a module reset. Crash information is displayed at the console on the next reboot.

Table 13: Troubleshooting Abnormal LED Activity on Modules

Diagnostic Signs	Possible Problems	Actions
POWER A (PA) LED is not lit POWER B (PB) LED is not lit	System is not receiving power from Power A. System is not receiving power from Power B.	Make sure Power A and Power B terminal connections are securely attached. Verify that power switches are on. Make sure connections to power sources are securely attached. If system still does not operate, contact the Juniper Networks Technical Assistance Center.
FAIL LED lights	The line module and IOA are incompatible. A hardware failure, such as a failed module.	Make sure that the line modules and IOAs are compatible; replace if necessary. If you replaced the IOA only, issue the reload slot slot_number command. If you replaced the line module or if there was a hardware failure, the system is supposed to automatically reset the module. If the condition persists, contact the Juniper Networks Technical Assistance Center.
FAN OK LED does not light FAN FAIL LED lights	Fan is not working properly or has slowed down. Fan needs replacement.	Contact the Juniper Networks Technical Assistance Center; the system must be serviced. Note: In the fan tray for the E320 router, four of the eight fans turn on immediately upon initial power-up and the other four fans turn on after a delay of 10 seconds.
LINK LED is not lit	Ethernet connection is down.	Make sure that Ethernet cables are properly connected to both the Ethernet port and the appropriate network device. If the condition persists, contact the Juniper Networks Technical Assistance Center.
ALM LED is red	System does not recognize a port connection. Cabling is not connected properly. Cable is faulty. Clocking problem exists.	Make sure that all cables are firmly plugged into the ports and the attached network device. Verify that cables are clean. Test for faulty cables. Verify clock source and configuration. Reset the system. NOTE: Problem is corrected when normal LED activity occurs.
ALM LED is yellow	Far end receive failure (FERF) exists.	Correct FERF problem. Reset the system. NOTE: Problem is corrected when normal LED activity occurs.
PA, FO, and LK LEDs on SRP module are on, but are off on LM and SFM module	Thermal protection mode has been enabled. System temperature is too high. Vents are blocked. Fans are not operating.	Look at your console for a message indicating the problem. If you have the system log set to a severity of WARNING or higher, a Warning message indicates the failure. Issue the show environment command to display the temperatures. If the temperature is too high, power down the system. Regulate temperature. Reset the system.

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