Optics and Hardware Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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Optics and Hardware Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

Types of OLS alarms and their troubleshooting procedures

Updated: June 16, 2026

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This topic explains the main optical line system (OLS) alarm types that the QDD OLS pluggable reports and links to the troubleshooting procedure for each alarm.

This table summarizes the main OLS (Optical Line System) alarm types and provides brief descriptions of each, along with the associated troubleshooting procedure:

Table 1. Summary of OLS alarms and troubleshooting procedures
Alarm Type	Description	Troubleshooting Procedure
RX LOS (Loss of Signal)	Indicates that the receiver is not detecting any input optical signal.	Rx LOS troubleshooting
RX Power Fail Low	Receiver optical power is below the expected operational threshold.	RX Power Fail Low troubleshooting
TX Power Fail Low	Transmitter optical output power is lower than the required specification.	TX Power Fail Low troubleshooting
Egress Amplifier Gain Low	Amplifier output gain is below the configured minimum.	Egress Amplifier Gain Low troubleshooting
Egress Amplifier Gain High	Amplifier output gain exceeds the allowable maximum, potentially causing distortion.	Egress Amplifier Gain High troubleshooting
Egress Auto Laser Shut	System automatically shuts the laser to prevent damage or ensure safety due to detected fault.	Egress Auto Laser Shut troubleshooting
Egress Auto Power Red	System detects reduced power and triggers automatic power reduction or shutdown for protection.	Egress Auto Power Red troubleshooting

Clear the RX-LOS-P alarm

Resolve the RX-LOS-P loss of signal alarm reported on the controller.

The RX-LOS-P alarm is raised when there is loss of signal.

Default Severity: Critical

Logical Object: Controller

Follow these steps to clear the RX-LOS-P alarm:

Procedure

	1.	Verify the transmission (TX) at the peer end.
	2.	Check the fiber connections.

The RX-LOS-P alarm is cleared if the signal is restored to normal.

What to do next

If the alarm does not clear, go to the Cisco Technical Support Website for additional troubleshooting assistance or contact Cisco TAC at 1 800 553-2447.

Clear the RX-POWER-FAIL-LOW alarm

Resolve the RX-POWER-FAIL-LOW alarm reported on the controller.

The RX-POWER-FAIL-LOW alarm is raised when the RX power is below the configured low threshold values.

Default Severity: Minor (MN), Non-Service-Affecting (NSA)

Logical Object: Controller

Follow these steps to clear the RX-POWER-FAIL-LOW alarm:

Procedure

	1.	Verify the transmission (TX) at the peer end.
	2.	Check the fiber connections.
	3.	Increase the peer end gain or transmit-power value to obtain the RX power above the threshold.

The RX-POWER-FAIL-LOW alarm is cleared if the RX power is increased above the threshold value.

What to do next

If the alarm does not clear, go to the Cisco Technical Support Website for additional troubleshooting assistance or contact Cisco TAC at 1 800 553-2447.

Clear the TX-POWER-FAIL-LOW alarm

Resolve the TX-POWER-FAIL-LOW alarm reported on the controller.

The TX-POWER-FAIL-LOW alarm is raised when the TX power is below the configured low threshold values.

Default Severity: Critical

Logical Object: Controller

Follow these steps to clear the TX-POWER-FAIL-LOW alarm:

Procedure

Increase the gain or power configuration value to obtain the TX power above the threshold.

The TX-POWER-FAIL-LOW alarm is cleared if the TX power is increased above the threshold value.

What to do next

If the alarm does not clear, go to the Cisco Technical Support Website for additional troubleshooting assistance or contact Cisco TAC at 1 800 553-2447.

Clear the EGRESS-AMPLI-GAIN-LOW alarm

Resolve the EGRESS-AMPLI-GAIN-LOW alarm reported on the controller.

The EGRESS-AMPLI-GAIN-LOW alarm is raised when the actual gain of the OLS pluggable is lower than the configured gain value.

Default Severity: Minor (MN), Non-Service-Affecting (NSA)

Logical Object: Controller

Follow these steps to clear the EGRESS-AMPLI-GAIN-LOW alarm:

Procedure

Configure the gain value within the optimum range.

The EGRESS-AMPLI-GAIN-LOW alarm is cleared when the gain value is set within the optimum range.

What to do next

If the alarm does not clear, go to the Cisco Technical Support Website for additional troubleshooting assistance or contact Cisco TAC at 1 800 553-2447.

Clear the EGRESS-AMPLI-GAIN-HIGH alarm

Resolve the EGRESS-AMPLI-GAIN-HIGH alarm reported on the controller.

The EGRESS-AMPLI-GAIN-HIGH alarm is raised when the actual gain of the OLS pluggable is higher than the configured gain value.

Default Severity: Minor (MN), Non-Service-Affecting (NSA)

Logical Object: Controller

Follow these steps to clear the EGRESS-AMPLI-GAIN-HIGH alarm:

Procedure

Verify the RX and TX values and adjust the gain within the optimum working range.

The EGRESS-AMPLI-GAIN-HIGH alarm is cleared when the gain value is set within the optimum range.

What to do next

If the alarm does not clear, go to the Cisco Technical Support Website for additional troubleshooting assistance or contact Cisco TAC at 1 800 553-2447.

Clear the EGRESS-AUTO-LASER-SHUT alarm

Resolve the EGRESS-AUTO-LASER-SHUT alarm reported on the controller.

The EGRESS-AUTO-LASER-SHUT alarm is raised when there is loss of signal (LOS) on the OTS line side (subport 1).

Default Severity: Not-Alarmed

Logical Object: Controller

Follow these steps to clear the EGRESS-AUTO-LASER-SHUT alarm:

Procedure

	1.	Verify the fiber connections on the line side of the OLS pluggable.
	2.	Verify the gain or power on the line side of the peer end.

The EGRESS-AUTO-LASER-SHUT alarm is cleared when there is no loss of signal on the OTS line side (subport 1).

What to do next

If the alarm does not clear, go to the Cisco Technical Support Website for additional troubleshooting assistance or contact Cisco TAC at 1 800 553-2447.

Clear the EGRESS-AUTO-POW-RED alarm

Resolve the EGRESS-AUTO-POW-RED alarm reported on the controller.

The EGRESS-AUTO-POW-RED alarm is raised when there is loss of signal (LOS) on the OTS line side (subport 1).

Default Severity: Not-Alarmed

Logical Object: Controller

Follow these steps to clear the EGRESS-AUTO-POW-RED alarm:

Procedure

	1.	Verify the fiber connections on the line side of the OLS pluggable.
	2.	Verify the gain or power on the line side of the peer end.

The EGRESS-AUTO-POW-RED alarm is cleared when there is lno oss of signal (LOS) on the OTS line side (subport 1).

What to do next

If the alarm does not clear, go to the Cisco Technical Support Website for additional troubleshooting assistance or contact Cisco TAC at 1 800 553-2447.

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