Configuration Guide for Cisco NCS 1001, IOS XR Release 25.x.x

Configure OTDR in automatic mode

Updated: July 27, 2026

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Use this procedure to configure automatic mode OTDR parameters so the device can run training and measurement phases with default or customized scan values.

Configure automatic mode to have OTDR prepare measurement parameters and run scans through automated training and measurement phases.

Automatic mode provides default values for scan parameters. Adjust values only if the fiber span requires a different measurement behavior.

Procedure

	1.	Enter configuration mode. Example: `configure`
	2.	Use the hw-module location command to enter OTDR automatic mode configuration for the slot, port, and direction. Example: `hw-module location 0/RP0/CPU0 slot 3 otdr port 1 direction tx scan auto`
	3.	Configure automatic mode parameters. See OTDR automatic-mode parameters for parameter descriptions, ranges, and defaults. Example: `loss-sensitivity 5 loss-relative-threshold 10 reflection-sensitivity -300 reflection-relative-threshold 5 total-loss 300 periodic-scan minutes 40`
	4.	Commit the configuration and exit configuration mode. Example: `commit end`

OTDR automatic mode is configured for the selected port and direction.

OTDR automatic mode parameters

Use these values when configuring OTDR in automatic mode.

Table 1. OTDR automatic mode parameters
Parameter	Description	Range	Default
loss-sensitivity (in 0.1 dB)	Limit under which the loss is not considered a real loss.	4 to 50	6
loss-relative-threshold (in 0.1 dB)	Threshold to compare the OTDR loss value plus the relative loss threshold with the baseline value.	1 to 300	2
reflection-sensitivity (in 0.1 dB)	Limit under which the reflection is not considered a real reflection.	-400 to -140	-300
reflection-relative-threshold (in 0.1 dB)	Threshold to compare the OTDR reflection value plus the relative reflection threshold with the baseline value.	1 to 300	2
total-loss (in 0.1 dB)	Loss from the near-end OTDR port to the far-end OTDR port, including span loss and additional EDFA filter loss.	1 to 500	200
periodic scan (minutes)	Automatically starts OTDR scans and repeats the scan after the periodic scan time elapses.	30 to 600000	30

Note

From Release 7.5.1, the plus sign labels in positive range values are removed in the Cisco NCS 1001 CLI help description.

Start OTDR measurement in automatic mode

Start automatic measurement after the OTDR automatic mode parameters are configured.

The scan continues in the background after the command starts the action.

Procedure

Use the hw-module command to start the OTDR automatic mode scan.

hw-module slot slot-number otdr port port-number direction direction scan auto

Example:

hw-module slot 3 otdr port 1 direction tx scan auto

The system displays the message "Otdr action will continue in the background."

What to do next

To see the measurement status, use the show hw-module slot slot-number otdr status command.

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