Understanding Status LEDs to Troubleshoot

Module LEDs can show you the immediate status of a module and alert you to a problem with the module or one of its ports. It is helpful to familiarize yourself with LED activity so that you can easily detect and correct a module-related problem with minimal or no system downtime.

LED Activity During Booting

When the system boots, it runs a series of tests for each module installed in the system, and the LEDs display various configurations. Refer to the tables in this section to understand normal and abnormal LED activity. For troubleshooting information, see Table 10-4.

LED Identification

The system's modules have two sets of status LEDs. The top set indicates generic router and module status. The bottom set indicates module-specific status, such as port status (line modules) or fan status (SRP module).

The number against the port status LED on a line module corresponds to the number of the port on the I/O module. Some line modules have more port status LEDs than the number of ports on the I/O module. In these cases, only the LEDs for the corresponding ports on the I/O modules are active.

For example, an OCx/STMx line module can pair with either an OC3-4 or an OC12/STM4 I/O module. Consequently, the line module has four port status LEDs for OC3/STM1 operation. However, only the top set of port status LEDs are active during OC12/STM4 operation.

Table 10-2 shows the functions of the module and port status LEDs.

Table 10-2 LED identification and activity descriptions 

LED Location	LED Label	LED Indicator	LED Color	OFF to ON	ON to OFF
All modules	OK	Module status	Green	Self-test passed	Failure detected
	FAIL	Module status	Red	Failure detected	Diagnostic test running
	ONLINE	Module status	Green	Module online	Module offine
All modules	REDUNDANT	Redundancy	Green	See Redundancy Status later in this chapter. Note: The REDUNDANT LED on the cOCx/STMx, FE-8, GE/FE, HSSI, OCx/STMx, and X.21/V.35 line modules is nonfunctional.
SRP module	POWER A OK	Power	Green	Power online on source A	Power off
	POWER B OK	Power	Green	Power online on source B	Power off
	FAN OK	Fan	Green	Fan online	Fan failure
	FAN FAIL	Fan	Red	Fan failure	Fan online
	LINK	Ethernet	Green	Ethernet link up	Ethernet link down
	ACTIVITY	Ethernet	Green	Blinks when Ethernet traffic on link	No Ethernet traffic on link
Ethernet line modules	LINK	Ethernet	Green	Ethernet link up	Ethernet link down
	ACTIVITY	Ethernet	Green	Blinks when Ethernet traffic on link	No Ethernet traffic on link
HSSI line module	SYNC	Port status	Green	If the port is configured as DTE, the LED lights when both the DCE and the clock source are available. If the port is configured as DCE, the LED lights when the DTE is available.	If the port is configured as DTE, the LED goes out when either the DCE or the clock source becomes unavailable. If the port is configured as DCE, the LED goes out when the DTE becomes unavailable.
	YEL ALM	Note: This LED is not functional on the HSSI line module.
	RED ALM	Port status	Red	If the port is configured as DTE, the LED lights when either the DCE or the clock source becomes unavailable. If the port is configured as DCE, the LED lights when the DTE becomes unavailable.	If the port is configured as DTE, the LE goes out when both the DCE and the clock source are available. If the port is configured as DCE, the LED goes out when the DTE is available.
X.21/V.35 line module	ACTIVE	Port status	Green	Port configured	Port not configured
	LOOPBK	Port status	Yellow	Port in local loopback or remote loopback, depending on the type of connection. (See)	Port not in loopback
	ERROR	Port status	Red	Port is enabled or comes online	Port is disabled or goes offline
	V.35	Port status	Green	V.35 cable connected	V.35 cable disconnected
	X.21	Port status	Green	X.21 cable connected	X.21 cable disconnected
	DCE	Port status	Green	DCE cable connected	DCE cable disconnected
	DTE	Port status	Green	DTE cable connected	DTE cable disconnected
Other line modules	SYNC	Port status	Green	In frame	Not in frame
	YEL ALM	Port status	Yellow	Far end receive failure (FERF) exists	No FERF present
	RED ALM	Port status	Red	Loss of sync/frame	In frame

The following figures show a representative module for each of the three variations:

• SRP module (Figure 10-1)
• Ethernet line module (Figure 10-2)
• Other line modules (Figure 10-3)

Figure 10-1 SRP module LEDs

Note: The primary SRP module illuminates the REDUNDANT LED only when the SRP module detects that there is a secondary or standby SRP module online. The standby SRP module monitors an activity signal from the primary SRP module to determine its state; it does not shadow the operations of the primary SRP module. If the standby SRP module detects that the primary SRP module is not active, it reboots the system and takes control. (ERX-7xx/14xx models only)

Figure 10-2 FE2 module LEDs

Figure 10-3 E3 and T3 module LEDs

LED Activity During Booting

When the system boots, it runs diagnostic tests, and the module status LEDs display various configurations. Observe the scenario presented in Table 10-3 to verify that the system has booted properly.

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

Table 10-3 Normal activity of functional status LEDS during booting 

OK	FAIL	ONLINE	Status Process
off	on	off	1    Module is in the power-up restart state; the FAIL LED stays on briefly.
off	off	off	2    Module is initializing, and diagnostic tests are running.
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 turns on. Some failure conditions may cause the board not to boot. In this case, the LEDs may all be off. The system should then reset the board.

If the operational software detects an error, the FAIL LED turns on. Some errors may cause a board reset. Crash information can be displayed from the console and is printed to the screen on the next reboot.

Abnormal LED Activity

See Table 10-4 to diagnose and correct problems.

Table 10-4 Troubleshooting abnormal LED activity on modules 

Diagnostic Signs	Possible Problems	Actions
POWER A OK is not lit POWER B OK is not lit	System is not receiving power from Power A. System is not receiving power from Power B.	1    Check Power A and Power B terminal connections. 2    Verify that power switches are on. 3    Check connections to power sources. 4    If system still does not operate, contact Juniper Networks Customer Service.
FAIL LED lights	The line module and I/O module are incompatible. A hardware failure, such as a failed module.	1    Check that the line and I/O modules are compatible; replace if necessary. 2    If you replaced the I/O module only, issue the reload slot slot_number command. 3    If you replaced the line module or if there was a hardware failure, the system should automatically reset the module. 4    If condition persists, contact Juniper Networks Customer Service.
FAN OK does not light FAN FAIL LED lights	Fan is not working properly or has slowed down. Fan needs replacement.	Contact Juniper Networks Customer Service; the system must be serviced.
LINK LED is not lit	Ethernet connection is down.	1    Check that Ethernet cables are properly connected to both the Ethernet port and the appropriate network device. 2    Contact Juniper Networks Customer Service.
RED ALM	System does not recognize a port connection. Cabling is not connected properly. Cable is faulty. Clocking problem exists.	1    Check that all cables are firmly plugged into the ports and the attached network device. 2    Verify that cables are clean. 3    Test for faulty cables. 4    Verify clock source and configuration. 5    Reset system. Note: Problem is corrected when normal LED activity is observed.
YEL ALM Note: This LED is not functional on the HSSI line module.	Far end receive failure (FERF) exists.	1    Correct FERF problem. 2    Reset system. Note: Problem is corrected when normal LED activity is observed.
System will not boot. Module(s) held offline. FAIL LED lights.	A slot group is overloaded.	1    Issue the show version command to display board status. 2    Review section on proper slot group configuration in Chapter 5, Installing Modules. 3    Reconfigure system with correct slot group configuration. 4    Reset system.
None	System temperature is too high. Vents are blocked. Fans are not operating.	1    Check 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 indicating the failure is displayed. 2    Issue the show environment command to display the temperatures. If the temperature is too high, power down the system. 3    Regulate temperature. 4    Reset system.

Redundancy Status

You can determine the redundancy state of line modules by examining the online and redundant status LEDs (ERX-7xx/14xx models only). See Table 10-5.

Note: The REDUNDANT LED on the cOCx/STMx, FE-8, GE/FE, HSSI, and OCx/STMx modules is nonfunctional.

Table 10-5 Redundancy status of a line module 

ONLINE LED	REDUNDANT LED	State of the Line Module
Off	Off	Module is booting or is an inactive primary line module.
On	Off	Module is active, but no standby module is available.
Off	On	Module is in standby state.
On	On	Module is active, and a standby module is available.