Cisco NCS 1010 Optical Applications Configuration Guide, IOS XR Release 26.x.x

PDF

Cisco NCS 1010 Optical Applications Configuration Guide, IOS XR Release 26.x.x

Baseline threshold

Updated: September 19, 2026

Want to summarize with AI?

Log in

This section explains how the system compares measured receive signal span loss with stored turn-up values and raises an alarm when configured deviation limits are exceeded.

Table 1. Feature History

Feature Name

Release Information

Description

Span Loss Baseline Deviation Monitoring

 Cisco IOS XR Release 26.1.1

You can now configure minimum and maximum deviation values to monitor the measured Rx signal span loss against the baselined value. The valid range is defined as baselined span loss − minimum deviation (lower limit) and baselined span loss + maximum deviation (upper limit). If the measured Rx span loss falls outside this calculated range, a SPAN-LOSS-BASELINE-DEVIATION-OUT-OF-RANGE alarm is raised.

Commands added:

  • max-baseline-deviation

  • min-baseline-deviation

After network turn-up, ALC saves the Rx and Tx span loss values on all nodes as a baseline. These values are then compared with the user-configured minimum and maximum threshold values.

The system subtracts the configured min-baseline-deviation value from the baselined span loss to determine the lower threshold, and adds the max-baseline-deviation value to determine the upper threshold.

If the measured Rx signal span loss falls outside the configured range, the SPAN-LOSS-BASELINE-DEVIATION-OUT-OF-RANGE alarm is raised. The range is defined by:

  • Lower limit = baselined span loss − min-baseline-deviation

  • Upper limit = baselined span loss + max-baseline-deviation

For example, if the baselined span loss is 20 dB, the minimum deviation is 1 dB, and the maximum deviation is 3 dB:

  • Lower limit = 20 − 1 = 19 dB

  • Upper limit = 20 + 3 = 23 dB

The alarm is raised only if the measured span loss drops below 19 dB or exceeds 23 dB.

Threshold hysteresis

The hysteresis value for alarms is used to prevent frequent toggling when the threshold parameter fluctuates around the threshold value. The hysteresis value for the SPAN-LOSS-BASELINE-DEVIATION-OUT-OF-RANGE alarm is 0.5 dBm.

Configure baseline threshold

Use this task to configure the minimum and maximum threshold values for baseline span loss.

Procedure

  1. Use the optical-line-control command to select the controller on which the baseline threshold must be configured.

    Example:

    
RP/0/RP0/CPU0:ios#configure 
RP/0/RP0/CPU0:ios(config)#optical-line-control 
RP/0/RP0/CPU0:ios(config-olc)#controller ots 0/0/0/0

  2. Use the span-loss min-baseline-deviation command to configure the minimum and maximum baseline span loss threshold values.

    Example:

    
RP/0/RP0/CPU0:ios(config-olc-ots)#span-loss min-baseline-deviation 200
RP/0/RP0/CPU0:ios(config-olc-ots)#span-loss max-baseline-deviation 300

  3. Commit the changes and exit all the configuration modes.

    Example:

    
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
RP/0/RP0/CPU0:ios(config-olc)#exit
RP/0/RP0/CPU0:ios(config)#exit

  4. Use the show running-config optical-line-control controller Ots command to verify the configured values.

    The entries in bold display the configured minimum and maximum threshold values for baseline span loss.

    Example:

    RP/0/RP0/CPU0:NCS1020_P1D_04#show running-config optical-line-control controller Ots 0/0/0/0
Mon Sep  9 12:48:52.008 IST
optical-line-control
 controller Ots0/0/0/0
  psd 1 -64
  psd 2 -63
  ...
  psd-min -226
  apc manual
  otdr    
   auto-scan enable
  !       
  raman-tuning disable
  gain-estimator manual
  fiber-type SMF
  span-loss max-baseline-deviation 35
  span-loss min-baseline-deviation 0
  span-loss payload-osc-max-deviation 100
  span-loss payload-osc-min-deviation 80
  link-tuner spectrum-density 93
  link-tuner manual
  apc-span-mode RX
  apc-span-mode TX
  span-length 1005
  connector-loss rx 0.5
  connector-loss tx 0.5
  apc-span-loss-correction-threshold RX 5
  apc-span-loss-correction-threshold TX 5

Baseline threshold values are configured on the nodes.