Troubleshoot "Auto Ampli Control Disabled Alarm" in NCS1K

Introduction

This document describes how to troubleshoot the low transmit power from the amplifier by clearing the "Auto ampli control disabled" alarm. 

Troubleshoot "Auto Ampli Control Disabled Alarm" in NCS1K

You see low transmit power and low gain from the Erbium Doped Fiber Amplifier (EDFA) since the Auto Ampli control is disabled.

show controller ots 0/x/0/x:

Amplifier performance valuesAlarm on the node

The "Auto Ampli Control Disabled" alarm raises if the power level difference between two channels exceeds the delta value configured. 

In this case, the Delta value was 5dB but the difference between the channels was more than 5dB, 

show hw-module slot x channel-trail-view active :

channel power view
Here some channels receive power as -12.xx and channel no 21 receives power as -18.xx, so the difference is 6dB which is more than the Delta value.

When the difference is more than the delta value, the Amplifier control is disabled. You still see the output power but the gain regulation does not happen as per design.

To check the delta value:show controler ots 0/x/0/x

Sample Output:

controller State: Up
Transport Admin State: In Service
Port Type: Line

Laser State: On
 Optics Status::
         Alarm Status:

         -------------
         Detected Alarms:
                 AUTO-AMPLI-CTRL-DISABLED 
         Alarm Statistics:
         -----------------
         LOW-RX-PWR = 0      
         LOW-TX-PWR = 0  
         RX-LOS-P = 5         
         RX-LOC = 1          
         AMPLI-GAIN-DEG-LOW = 0         
         AMPLI-GAIN-DEG-HIGH = 0         
         AUTO-LASER-SHUT = 5         
         AUTO-POW-RED = 5         
         AUTO-AMPLI-CTRL-DISABLED = 5         
         AUTO-AMPLI-CFG-MISMATCH = 0         
         SWITCH-TO-PROTECT = 0         
         AUTO-AMPLI-CTRL-RUNNING = 2         
         Parameter Statistics:
         ---------------------
         TX Power = 3.80 dBm
         RX Power = -9.70 dBm
         Ampli Gain = 19.50 dB
         Ampli Tilt = 0.00
         Total TX Power = 4.09 dBm
         Total RX Power = -8.50 dBm
         Ampli Gain Range = Normal
         Ampli Safety Control mode = auto
         Osri = OFF
         TX Enable = Enabled
         RX Enable = Enabled
         RX Span Loss = N/A
         TX Span Loss = N/A
         Rx Low Threshold Current = -25.0 dBm
         Back Reflection = -27.30 dBm
         Configured Parameters:
         -------------
         Rx Low Threshold = -25.0 dBm
         Tx Low Threshold = -20.0 dBm
         Ampli Gain = 1.00 dB
         Ampli Tilt = 0.00
         Ampli Channel power = 3.00 dBm
         Channel Power Max Delta = 3.00 dBm
         Ampli Channel Psd = 31.250 nW/MHz
         Rx Low Threshold Psd = 0.099 nW/MHz
         Ampli Control mode = Automatic
         Ampli Safety Control mode = auto
         Osri = OFF
         TX Enable = Enabled
         RX Enable = Enabled

Here the delta value is 3dB and the difference between the channels was 6dB.

Permanent Solution:

Check the patchpanel for the channels that have less power.

Clean/replace the patch cords if required in order to improve the channel power.

Once the power becomes equal to or less than the delta value, the alarm clears and the output power gets regulated as required.

Workaround:

A temporary workaround is to increase the delta value with these configuration changes to restore the traffic:

config ter

controller ots 0/x/0/x

channel-power-max-delta 80 (change delta to 8)

Ensure to revert the configuration to the default delta value once the permanent solution gets implemented.