The NCS 1010 OLT and ILA nodes have an in-built bidirectional Optical Time Domain Reflectometer (OTDR) functionality that can run in line with DWDM channels. The OTDR captures real-time measurements of loss and back reflection of the fiber pair linked to the TX and RX ports.

Note	For the OLT device, the OTDR port can switch between LINE-TX and LINE-RX ports, whereas in the ILA device, the OTDR port can switch among LINE-1-TX, LINE-1-RX, LINE-2-TX, and LINE-2-RX ports.

You can use this feature to check the fiber quality during system installation (before traffic is active), especially in case RAMAN is used. It can also be used to monitor the fiber during the system operation (live traffic) and to check the fiber if cable cut and repair events.

You can view the OTDR measurement result in the SOR file that is exported from NCS 1010.

You can determine the following characteristics using OTDR:

• The attenuation (dB) of the whole fiber link and the attenuation of separate sections of fiber.

• The distance and magnitude of insertion loss, reflection loss.

• Fiber events such as concentrated loss events (with value and position), reflection events (with value and position), events at the end of the fiber, and discontinuities or defects on the fiber including loss events.

The NCS 1010 device uses the default values for OTDR scan parameters before the OTDR configuration.

You can configure the OTDR on the OTS controller. Use the following commands to configure the various OTDR parameters:

configure

controller ots R/S/I/P

otdr scan-mode expert

otdr rx auto reflectance-threshold value

otdr rx auto splice-loss-threshold value

otdr rx auto excess-reflection-threshold value

otdr rx auto back-scattering value

otdr rx auto refractive-index value

otdr tx auto reflectance-threshold value

otdr tx auto raman-setpoint value

otdr tx auto excess-reflection-threshold value

otdr tx auto splice-loss-threshold value

otdr tx auto back-scattering value

otdr tx auto refractive-index value

otdr rx expert pulse-width value

otdr rx expert capture-end value

otdr rx expert capture-start value

otdr rx expert scan duration value

otdr tx expert pulse-width value

otdr tx expert capture-end value

otdr tx expert capture-start value

otdr tx expert scan duration value

otdr tx expert scan duration value

Example:

RP/0/RP0/CPU0:ios#config
RP/0/RP0/CPU0:ios(config)#controller ots 0/0/0/0
RP/0/RP0/CPU0:ios(config-Ots)#otdr rx auto reflectance-threshold -50
RP/0/RP0/CPU0:ios(config-Ots)#otdr rx auto splice-loss-threshold 200
RP/0/RP0/CPU0:ios(config-Ots)#otdr rx expert pulse-width 6000
RP/0/RP0/CPU0:ios(config-Ots)#otdr tx auto reflectance-threshold -50
RP/0/RP0/CPU0:ios(config-Ots)#otdr tx auto splice-loss-threshold 200
RP/0/RP0/CPU0:ios(config-Ots)#otdr scan-mode expert
RP/0/RP0/CPU0:ios(config-Ots)#otdr scan-mode expert
RP/0/RP0/CPU0:ios(config-Ots)#commit

RP/0/RP0/CPU0:ios#config
RP/0/RP0/CPU0:ios(config)#controller ots 0/0/0/0
RP/0/RP0/CPU0:ios(config-Ots)#otdr rx auto reflectance-threshold -50
RP/0/RP0/CPU0:ios(config-Ots)#otdr rx auto splice-loss-threshold 200
RP/0/RP0/CPU0:ios(config-Ots)#otdr rx expert pulse-width 6000
RP/0/RP0/CPU0:ios(config-Ots)#otdr tx auto reflectance-threshold -50
RP/0/RP0/CPU0:ios(config-Ots)#otdr tx auto splice-loss-threshold 200
RP/0/RP0/CPU0:ios(config-Ots)#otdr scan-mode expert
RP/0/RP0/CPU0:ios(config-Ots)#otdr scan-mode expert
RP/0/RP0/CPU0:ios(config-Ots)#commit

NCS 1010 software does not support automatic start of OTDR scan. You have to start the OTDR scan manually using the otdr-start controller ots R/S/I/P direction command to perform the following procedures:

1. Identify the defect after the fiber has been cut.

2. Check the fiber quality after correcting the fiber defect.

3. Initiate an OTDR scan at the time of installation.

Example:

RP/0/RP0/CPU0:ios#otdr-start controller ots 0/0/0/0 rx 
Wed Feb  9 05:49:39.178 UTC
OTS OTDR Scan Started at RX
RP/0/RP0/CPU0:ios#

The Raman tuning application locks the OTDR scan at both fiber ends before the tuning starts, and releases the lock after the tuning completes. Therefore, when you try to start the OTDR scan when Raman tuning is running, your request gets rejected. The following example explains the OTDR start request rejection. The OTDR scan request that has been rejected already does not run automatically after the lock is released, so you have to create a new request to start the OTDR again.

RP/0/RP0/CPU0:ios#otdr-start controller ots 0/0/0/0 rx
Tue Feb 28 10:25:43.379 UTC
OTDR Scan cannot be started as it is locked by Another Entity/Application.
RP/0/RP0/CPU0:ios#

RP/0/RP0/CPU0:ios#otdr-start controller ots 0/0/0/0 tx
Tue Feb 28 10:25:53.379 UTC
OTDR Scan cannot be started as it is locked by Another Entity/Application.
RP/0/RP0/CPU0:ios#

To stop the OTDR scan function, use the following otdr-stop controller ots R/S/I/P direction command:

Example:

RP/0/RP0/CPU0:ios#otdr-stop controller ots 0/0/0/0 rx 
Wed Feb  9 06:03:37.406 UTC
OTS OTDR Scan Stopped at RX
RP/0/RP0/CPU0:ios#

You can use the show controllers ots R/S/I/P otdr-info direction command to view the OTDR scan events and the location of the SOR file.

The SOR file contains the fiber trace details such as the distance, reflectance, loss, and fiber attenuation measurements. You can export the SOR file.

Note	To transfer the SOR file from the source to the destination, use the following command: scp username@device-ip:filename_with_source_location destination-location Example: scp test@192.168.0.1:/harddisk:/otdr/ios_OTDR_Ots0_0_0_0_RX_20230301-101927.sor /users/test/

OTDR can detect typical fiber events such as loss due to fiber splicing, patch panel, and coupler connections, single and multiple loss events, single and multiple reflective events, fiber pinch, and fiber cut.

The following is the sample to display the OTDR scan information in the RX direction.

RP/0/RP0/CPU0:ios#show controllers ots 0/0/0/0 otdr-info rx 
Wed Feb  9 05:55:19.791 UTC
       Scan Direction: RX
       Scan Status: Data Ready 
       SOR file: /harddisk:/otdr/IOS_NCS1010_OTDR_Ots0_0_0_0_RX_20220209-055045.sor
       Total Events detected: 11 
       Scan Timestamp: Wed Feb  9 05:50:45 2022 UTC
       Event Type Legend:  NR:Non-Reflective  R:Reflective  FE:Fiber-End  ER:Excess-Reflection
      Event#  | Detected Event(s) | Location(km) | Accuracy(m) | Magnitude(dB)| Attenuation/km(dB)
      1       | R                 | 50.4709      | 52.47       | -39.87       |  0.18            
      2       | NR                | 50.4709      | 52.47       | 1.17         |  0.18            
      3       | R                 | 100.9261     | 102.92      | -37.73       |  0.21            
      4       | NR                | 100.9261     | 102.92      | 1.01         |  0.21            
      5       | R                 | 105.9500     | 107.94      | -38.52       |  0.24            
      6       | NR                | 105.9500     | 107.94      | 0.85         |  0.24            
      7       | R                 | 112.7458     | 114.74      | -40.56       |  0.00             
      8       | NR                | 112.7458     | 114.74      | 1.48         |  0.00            
      9       | NR                | 117.9873     | 119.98      | 0.66         |  -0.02           
      10      | R FE              | 120.1206     | 122.12      | -35.55       |  0.00            
      11      | NR FE             | 120.1206     | 122.12      | 21.65        |  0.00            
 

Note	After the FPD upgrade of the line card, the results of previous OTDR scans may not be available using the CLI command show controllers ots Rack/Slot/Instance/Port otdr-info direction. However, you can get the results of previous OTDR scans in the form of .SOR files that are stored in the hard disk.