Cisco NCS 1020 Optical Applications Configuration Guide, IOS XR Release 24.3.x

Overview of Automatic Power Control

On a fiber, the power level may vary between channels. Over long distances and multiple amplifications, these differences in power levels can result in deterioration of the quality of some channels. Automatic Power Control (APC) corrects the power level differences and ensures that power for different channels is according to the target power profile for the spectrum. APC compensates for the degradation of the network over time. APC is enabled if automatic link bring up is enabled.

APC is a network-level feature that is distributed among different nodes. An APC domain is a set of nodes that is controlled by the same instance of APC at the network level. An APC domain identifies a portion of the network that can be independently regulated. The source OLT node acts as the APC Manager or Domain Manager for all the nodes in the path. The subsequent nodes in the path act as APC agent nodes. The manager node enables APC on agent nodes, monitors DISCREPANCY and initiates regulation if correction is required. To avoid large power fluctuations, APC adjusts power levels incrementally. APC performs power correction in steps of +/-0.8dB. This is applied to each iteration until the optimal power level is reached.

You can use APC as a span level application by using span-mode APC.

APC is direction-specific. You can enable APC for each direction at the transmitting OLT node. The source node enables and controls different parameters in all ILA nodes on the path and the far-end OLT ingress EDFA.

The following table lists the parameters that APC configures and controls in different nodes.


Node	Parameters
Transmitting OLT	EDFA Gain EDFA Tilt VOA Attenuation WSS Attenuation
ILA	EDFA Gain EDFA Tilt VOA Attenuation DGE Attenuation
Receiving OLT	EDFA Gain EDFA Tilt WSS Attenuation

When you enable APC, APC controls these parameters. APC overrides any manual configuration. When you disable APC, user configuration is applied.

APC divides the C band spectrum into 32 equal parts. APC uses 33 frequencies across the C band to divide the band. We call these 33 frequencies, setpoints. Each setpoint is 150 GHz apart from the adjacent setpoints. You can configure a power profile across the spectrum using these setpoints. You can configure the target PSD for each OLT and ILA node on a link.

APC applies amplification and attenuation as required at channel level and composite signal level to ensure that the channels are at the target power level. You can configure the target power spectral densities for 33 points across the band. If you enable link tuner, link tuner sets the target PSDs for APC on all nodes in the path.

APC performs the following functions:

APC monitors the current PSD against the target PSD for each channel (ASE and user channel) and changes the amplifier parameters including VOA, WSS, and DGE to achieve the target PSD.
APC detects optical network changes on the path and alters the amplifier parameters on the nearest nodes to compensate for the changes. APC performs these alterations in multiple steps.
APC collects measurements from other link nodes at the transmitting OLT to precisely locate optical network changes.

APC regulation begins as soon as it discovers any part of the topology. At a transmitting OLT, it starts power correction at the OLT and subsequent ILA nodes even if the complete OLT-OLT link has not been discovered.

Note

If the input slice power of a channel is below psd-min and APC is unable to bring the channel above psd-min even after setting the WSS attenuation to 0dB, APC declares the channel as failed.
After APC regulation, all channel powers must be above psd-min (-24-dBm default) and at least one channel should be within 0.5 dB of psd-min.

View APC Status and Information

Use the show olc apc command to view APC status.

The following sample is an output of show olc apc command when APC is in Centralized mode.

RP/0/RP0/CPU0:OLT1#show olc apc

Controller      : Ots0/0/0/0
APC Status      : WORKING

Node RID        : 10.1.1.1
Internal State  : IDLE

Node RID        : 10.99.1.2
Internal State  : IDLE

Node RID        : 10.99.2.2
Internal State  : IDLE

Node RID        : 10.99.4.1
Internal State  : IDLE

Node RID        : 10.1.1.5
Internal State  : DISCREPANCY

The following sample is an output of show olc apc command when APC is in span-mode.

RP/0/RP0/CPU0:ios#show olc apc

Controller      : Ots0/0/0/0
APC Status      : MANUAL

APC Status is the status of APC in the complete path. The following table lists and describes the APC Statuses.


APC Status	Description
BLOCKED	APC moves to BLOCKED state if: there is an event in the network which resulted in topology failure an amplifier safety event like APR or OSRI has been triggered in the network APC is locally disabled on agent node
PAUSED	APC is paused using the apc-pause command.
IDLE	APC regulation has been completed successfully. All the channels in the network have achieved the target PSD provided by Link-tuner or configured by user
WORKING	APC detected a DISCREPANCY between current and target PSD. APC regulation is in progress to converge the power to target PSD.
DISABLED	APC is disabled.
PARTIAL-TOPOLOGY NODE-BLOCKED	APC has limited visibility. APC manager does not have visibility to the full OLT-OLT topology. APC manager tries to correct the power levels on the agent nodes that are reachable and after the regulation is complete, APC moves to BLOCKED state.
Manual

Internal State is the state of APC on each individual node. The following table lists and describes the internal states.


APC Internal State	Description
DISCREPANCY	The APC manager flags an agent node which needs correction when there is a discrepancy between target PSD and current PSD. This state is temporary and lasts until APC starts power correction and goes into CORRECTING state.
CORRECTING	APC correction is in progress on the node
OOR	APC-OUT-OF-RANGE condition is raised on an agent node when APC fails to regulate and achieve the target PSD power level because the requested gain or attenuation setpoint cannot be set due to one of the following conditions: Amplifier gain is exhausted in the current gain range. WSS range (0-25dB) is exhausted for a single or multiple channels. DGE range (0-3dB) is exhausted for a single or multiple channels. Spanloss increased and amplifier gain is insufficient to achieve target PSD
IDLE	APC regulation has been completed successfully. All the channels in the network have achieved the target PSD provided by Link-tuner or configured by user
BLOCKED	APC is unable to perform for the following reasons: OSRI has shut down the amplifier: AMPLI-SHUT APC is disabled locally on the node: USER-DISABLED Gain Estimation is in progress: GAIN-ESTIMATION-IN-PROGRESS Amplifier auto power reduction is enabled: AMPLI-APR-ENABLED Amplifier is shut because of loss of input power: AMPLI-SHUT An event in the network resulted in topology failure.

The following sample is an output of show olc apc command when OSRI has shut down an amplifier in the link.

RP/0/RP0/CPU0:ios#sh olc apc
Thu Jul  7 13:21:05.807 UTC

Controller      : Ots0/0/0/0
APC Status      : BLOCKED

Node RID        : 10.1.1.1
Internal State  : IDLE

Node RID        : 10.1.1.2
Internal State  : BLOCKED
Blocked Reason  : [ AMPLI-SHUT ]

Node RID        : 10.1.1.3
Internal State  : DISCREPANCY

Node RID        : 10.1.1.4
Internal State  : DISCREPANCY

Node RID        : 10.1.1.5
Internal State  : DISCREPANCY

The following sample is an output of show olc apc command when APC is disabled locally on a node.

RP/0/RP0/CPU0:ios#sh olc apc
Thu Jul  7 13:22:44.145 UTC

Controller      : Ots0/0/0/0
APC Status      : BLOCKED

Node RID        : 10.1.1.1
Internal State  : IDLE

Node RID        : 10.1.1.2
Internal State  : BLOCKED
Blocked Reason  : [ USER-DISABLED ]

Node RID        : 10.1.1.3
Internal State  : DISCREPANCY

Node RID        : 10.1.1.4
Internal State  : DISCREPANCY

Node RID        : 10.1.1.5
Internal State  : DISCREPANCY

The following sample is an output of show olc apc command when Gain Estimation is in progress on a node.

RP/0/RP0/CPU0:ios#sh olc apc
Tue Jun 7 11:43:10.801 UTC

Controller : Ots0/0/0/0
APC Status : BLOCKED

Node RID : 10.1.1.1
Internal State : DISCREPANCY

Node RID : 10.1.1.2
Internal State : DISCREPANCY

Node RID : 10.1.1.3
Internal State : BLOCKED
Blocked Reason : [ GAIN-ESTIMATION-IN-PROGRESS ]

The following sample is an output of show olc apc command when amplifier auto power reduction is enabled on a node.

RP/0/RP0/CPU0:ios#sh olc apc
Thu Jul  7 13:21:49.530 UTC

Controller      : Ots0/0/0/0
APC Status      : BLOCKED

Node RID        : 10.1.1.1
Internal State  : IDLE

Node RID        : 10.1.1.2
Internal State  : BLOCKED
Blocked Reason  : [ AMPLI-APR-ENABLED ]

Node RID        : 10.1.1.3
Internal State  : DISCREPANCY

Node RID        : 10.1.1.4
Internal State  : DISCREPANCY

Node RID        : 10.1.1.5
Internal State  : DISCREPANCY

You can view the local status of APC on each node using the show olc apc-local command. This command shows if APC is enabled or disabled on the node.

The following sample is an output of show olc apc-local command when APC is in centralized mode.

RP/0/RP0/CPU0:ios#show olc apc-local
Mon Apr 11 06:59:14.679 UTC

Controller : Ots0/0/0/0

TX Status : ENABLED
RX Status : ENABLED

The following sample is an output of show olc apc-local command when APC is in spam mode.

RP/0/RP0/CPU0:SOLN-OLT-1#show olc apc-local 
Tue Jun 11 10:57:00.797 IST

Controller :  Ots0/0/0/0

Tx Status : SPAN-MODE
Rx Status : SPAN-MODE

You can view the target PSDs configured for all setpoints using the show olc apc-local target-psd-profile command. The output shows the source of the PSD configuration also. The target PSD source can be Link Tuner or Configuration.

The following sample is an output of show olc apc-local target-psd-profile command.

RP/0/RP0/CPU0:ios#show olc apc-local target-psd-profile
Tue Apr 26 10:19:24.910 UTC
Controller          : Ots0/0/0/0
Target PSD source   : Configuration
-------------------------------------------------------------------------------
Setpoint                Frequency                        Target PSD
                          (THz)                        (dBm/12.5 GHz)
-------------------------------------------------------------------------------
01                    191.337494                           15.0
02                    191.488678                           15.0
03                    191.639847                           -4.1
04                    191.791016                           -4.1
05                    191.942184                           -4.1
06                    192.093353                           -4.1
07                    192.244537                           -4.1
08                    192.395706                           -4.1
09                    192.546875                           -4.1
10                    192.698044                           -4.1
11                    192.849213                           -4.1
12                    193.000397                           -4.1
13                    193.151566                           -4.1
14                    193.302734                           -4.1
15                    193.453903                           -4.1
16                    193.605072                           -4.1
17                    193.756256                           -4.1
18                    193.907425                           -4.1
19                    194.058594                           -4.1
20                    194.209763                           -4.1
21                    194.360931                           -4.1
22                    194.512115                           -4.1
23                    194.663284                           -4.1
24                    194.814453                           -4.1
25                    194.965622                           -4.1
26                    195.116791                           -4.1
27                    195.267975                           -4.1
28                    195.419144                           -4.1
29                    195.570312                           -4.1
30                    195.721481                           -4.1
31                    195.872650                           -4.1
32                    196.023834                           -4.1
33                    196.175003                           -4.1

You can view the detailed information about APC on each node using the show olc apc-local regulation-info command. This command provides the following information:

Controller
APC Domain Manager
Internal Status
Minimum PSD
Last correction timestamp
Gain range
Amplifier and attenuation parameters: Configured and current values and available ranges
Detailed information on the channels

The following details are available:
- Center frequency of each channel
- Channel width
- Channel ID
- Channel Source (ASE or user channel)
- Slice number of the center frequency of the channel in the WSS
- PSD of the channel at the input of the amplifier
- Target PSD for the channel
- Current PSD of the channel
- Discrepancy between current and target PSD
- The configured attenuation on the WSS (OLT) or DGE (ILA) for the channel

You can view the APC information for only the Tx or Rx direction using the tx|rx keyword with the show olc apc-local regulation-info controller ots R/S/I/P command.

The following sample is an output of show olc apc-local regulation-info command.

RP/0/RP0/CPU0:ios#show olc apc-local regulation-info controller ots 0/0/0/0 tx
Wed Jul  6 05:01:45.177 UTC
Controller            : Ots0/0/0/0
Domain Manager        : 10.1.1.1
Internal Status       : OOR
Direction            : TX
PSD Minumum          : -24.0 (dBm/12.5 GHz)
Gain Range           : Normal
Last Correction      : 2022-07-06 05:01:28

  Device Parameters                 Min   Max  Configuration Operational
===========================================================================
  Egress Ampli Gain (dB)           :15.4  29.4 19.5          19.5 
  Egress Ampli Tilt (dB)           :-5.0  3.1  -2.2          -2.2 
  TX Ampli Power (dBm)             : -    22.4  -            21.4
  TX VOA Attenuation (dB)          :0.0   20.0 0.0           0.0
  Egress WSS/DGE Attenuation (dB)  :0.0   25.0  -             - 


Channel Center Channel Channel Channel Spectrum   Ampli-Input      Target       Current    Discrepancy Channel Slice
  Frequency     Width    ID    Source  Slice Num      PSD           PSD           PSD                   Attn Config
    (THz)       (GHz)                            (dBm/12.5 GHz)(dBm/12.5 GHz)(dBm/12.5 GHz)    (dB)        (dB)
====================================================================================================================
 191.375000    75.00     1      OCh       13          -23.2         -4.6          -4.9         0.2        7.1
 191.449997    75.00     -      ASE       37          -23.0         -4.6          -4.7         0.1        9.2
 191.524994    75.00     -      ASE       61          -23.1         -4.6          -4.7         0.1        9.3
 191.600006    75.00     4      OCh       85          -23.1         -4.5          -4.7         0.1        8.0
 191.675003    75.00     -      ASE       109         -23.0         -4.5          -4.5         0.0        9.1
 191.750000    75.00     6      OCh       133         -23.0         -4.4          -4.6         0.1        8.0
 191.824997    75.00     -      ASE       157         -23.1         -4.4          -4.6         0.1        9.3
 191.899994    75.00     8      OCh       181         -23.0         -4.4          -4.4         0.0        8.0
 191.975006    75.00     -      ASE       205         -23.0         -4.3          -4.5         0.1        9.1
 192.050003    75.00     10     OCh       229         -23.0         -4.3          -4.5         0.1        8.2
 192.125000    75.00     -      ASE       253         -22.9         -4.3          -4.3         0.0        9.0
 192.199997    75.00     12     OCh       277         -22.8         -4.2          -4.3         0.0        8.3
 192.274994    75.00     -      ASE       301         -22.9         -4.2          -4.4         0.1        9.0
 192.350006    75.00     14     OCh       325         -22.6         -4.2          -4.2         0.0        8.3
 192.425003    75.00     -      ASE       349         -22.8         -4.2          -4.3         0.1        8.7
 192.500000    75.00     16     OCh       373         -22.4         -4.1          -3.9         -0.2       8.1
 192.574997    75.00     -      ASE       397         -22.7         -4.1          -4.2         0.1        8.6
 192.649994    75.00     18     OCh       421         -22.6         -4.1          -4.2         0.1        8.1
 192.725006    75.00     -      ASE       445         -22.7         -4.0          -4.2         0.1        8.6
 192.800003    75.00     20     OCh       469         -22.7         -4.0          -4.1         0.1        7.9
 192.875000    75.00     -      ASE       493         -22.6         -4.0          -4.0         0.0        8.4
 192.949997    75.00     22     OCh       517         -22.6         -3.9          -4.1         0.1        7.6
 193.024994    75.00     -      ASE       541         -22.5         -3.9          -4.0         0.1        8.2
 193.100006    75.00     24     OCh       565         -22.7         -3.8          -4.0         0.1        7.5
 193.175003    75.00     -      ASE       589         -22.7         -3.8          -4.0         0.1        8.2
 193.250000    75.00     26     OCh       613         -22.5         -3.8          -3.9         0.1        7.2
 193.324997    75.00     -      ASE       637         -22.6         -3.8          -4.0         0.2        8.1
 193.399994    75.00     28     OCh       661         -22.7         -3.7          -3.9         0.1        7.2
 193.475006    75.00     -      ASE       685         -22.5         -3.7          -3.8         0.1        8.0
 193.550003    75.00     30     OCh       709         -22.7         -3.7          -3.8         0.1        7.0
 193.625000    75.00     -      ASE       733         -22.7         -3.6          -3.8         0.1        8.1
 193.699997    75.00     32     OCh       757         -22.7         -3.6          -3.7         0.1        6.7
 193.774994    75.00     -      ASE       781         -22.7         -3.5          -3.7         0.1        8.2
 193.850006    75.00     34     OCh       805         -22.7         -3.5          -3.7         0.1        6.6
 193.925003    75.00     -      ASE       829         -22.7         -3.5          -3.6         0.1        8.1
 194.000000    75.00     36     OCh       853         -22.8         -3.5          -3.7         0.2        6.6
 194.074997    75.00     -      ASE       877         -22.8         -3.4          -3.6         0.1        8.3
 194.149994    75.00     38     OCh       901         -22.7         -3.4          -3.5         0.1        10.9
 194.225006    75.00     -      ASE       925         -22.8         -3.3          -3.5         0.1        8.2
 194.300003    75.00     40     OCh       949         -22.9         -3.3          -3.5         0.1        7.1
 194.375000    75.00     -      ASE       973         -22.8         -3.3          -3.4         0.1        8.4
 194.449997    75.00     42     OCh       997         -22.9         -3.2          -3.5         0.2        7.3
 194.524994    75.00     -      ASE       1021        -22.9         -3.2          -3.4         0.1        8.4
 194.600006    75.00     44     OCh       1045        -22.8         -3.2          -3.3         0.1        7.2
 194.675003    75.00     -      ASE       1069        -22.8         -3.2          -3.3         0.1        8.4
 194.750000    75.00     46     OCh       1093        -22.9         -3.1          -3.4         0.2        7.3
 194.824997    75.00     -      ASE       1117        -22.8         -3.1          -3.2         0.1        8.2
 194.899994    75.00     48     OCh       1141        -22.8         -3.0          -3.3         0.2        6.9
 194.975006    75.00     -      ASE       1165        -22.9         -3.0          -3.2         0.1        8.3
 195.050003    75.00     50     OCh       1189        -22.8         -3.0          -3.1         0.1        6.6
 195.125000    75.00     -      ASE       1213        -22.9         -3.0          -3.1         0.1        8.3
 195.199997    75.00     52     OCh       1237        -22.9         -2.9          -3.1         0.1        6.3
 195.274994    75.00     -      ASE       1261        -23.0         -2.9          -3.0         0.1        8.1
 195.350006    75.00     54     OCh       1285        -23.1         -2.8          -3.0         0.1        6.4
 195.425003    75.00     -      ASE       1309        -23.2         -2.8          -3.0         0.1        8.3
 195.500000    75.00     56     OCh       1333        -23.1         -2.8          -2.9         0.1        6.2
 195.574997    75.00     -      ASE       1357        -23.4         -2.8          -3.0         0.2        8.2
 195.649994    75.00     58     OCh       1381        -23.4         -2.7          -2.9         0.1        6.4
 195.725006    75.00     -      ASE       1405        -23.4         -2.7          -2.8         0.1        8.5
 195.800003    75.00     60     OCh       1429        -23.6         -2.7          -2.8         0.1        6.6
 195.875000    75.00     -      ASE       1453        -23.7         -2.6          -2.9         0.2        8.7
 195.949997    75.00     62     OCh       1477        -23.7         -2.6          -2.8         0.2        6.9
 196.024994    75.00     -      ASE       1501        -23.6         -2.5          -2.7         0.1        9.0
 196.100006    75.00     64     OCh       1525        -23.7         -2.5          -2.7         0.1        7.1


ASE - Noise Loaded Channel
OCh - Optical Channel

Note

In the previous sample output, the channel source is ASE for channels that are empty and for channels that failed due to power level dropping below psd-min. For dropped channels, channel ID is present and the channel source is ASE. ASE or Noise loader fills noise across the spectrum with a spacing of 75 GHz for wherever optical cross connects are not present.
When APC is in span-mode, the apc regulation info output does not show the channel source on ILA nodes

Configure APC

If you enable link tuner, the link tuner sets the target PSDs for APC on all nodes in the path.

You can configure the target power spectral densities for 33 points across the band. The 33 PSD values divide the entire spectrum into 150-GHz steps. APC uses the corresponding PSD value if the channel frequency corresponds to a configured point. If the central frequency is not on a configured position, APC computes the target PSD for a channel by extrapolating from the two adjacent steps.

Use the following commands to set the target PSDs for single-band for each node on a C-band network.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

psd <1-33> value

commit

end

The following is a sample configuration that sets the psd to 15 dBm/12.5 GHz for the setpoints 1 and 2.

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
RP/0/RP0/CPU0:ios(config-olc-ots)#psd 1 150
RP/0/RP0/CPU0:ios(config-olc-ots)#psd 2 150
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Disable APC

To disable APC for a link, execute the following commands on the transmitting OLT node.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

apc disable

commit

end

The following is a sample configuration that disables APC.

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
RP/0/RP0/CPU0:ios(config-olc-ots)#apc disable
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Important

When you disable APC, NCS 1020 sets all setpoints to values in the configuration. If there is no configuration, NCS 1020 sets all setpoints to default values. Disabling APC is traffic impacting.

Enable Centralized APC

To enable APC for a link, execute the following commands on the transmitting OLT node.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

apc enable

commit

end

The following is a sample configuration that enables APC.

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
RP/0/RP0/CPU0:ios(config-olc-ots)#apc enable
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Pause CentralizedAPC

If you want to modify the network without APC compensating for the changes, you can pause APC. Use the following commands to pause APC.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

apc-pause

commit

end

The following is a sample configuration that pauses APC.

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
RP/0/RP0/CPU0:ios(config-olc-ots)#apc-pause
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Note

If you run the apc-pause command when APC is in idle state, APC remains in the idle state until APC detects changes in the network that requires power correction. APC changes the status to paused after it detects changes, but does not perform power correction.
Running the apc-pause command, does not pause channel startup.

Disable Centralized APC on an ILA Node

If you want to manually disable APC on a particular node. For example, consider a scenario where the headend OLT encounters a headless event. For any power correction required at agent nodes, APC manager is unavailable to initiate regulation. Also, you cannot perform any adjustments as APC is enabled and user-configuration of target-psd does not take effect. This command gives you an option to disable APC locally on an agent node to perform the parameter adjustments manually. Use the apc-local disable command to disable APC on an agent node.

Use the following commands to disable APC on an ILA node.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

apc-local [ RX | TX ] disable

commit

end

The following is a sample configuration that disables APC locally.

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
RP/0/RP0/CPU0:ios(config-olc-ots)#apc-local RX disable
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Configure Target Drop PSD

Link Tuner does not set the target PSD for drop ports. The default target PSD for drop ports is -8.0 dBm/12.5 GHz. The NCS 1020 applies drop PSD configuration for channels with cross connect configurations. Use the drop-psd command to set the desired drop-psd.

Use the following commands to set the desired drop-psd.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

drop-psd value

commit

end

The following is a sample configuration that sets the target PSD at drop ports to –25 dBm/12.5 GHz.


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
RP/0/RP0/CPU0:ios(config-olc-ots)#drop-psd -250
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
Tue Apr 26 09:50:12.055 UTC
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Configure Minimum PSD

If the PSD of a channel with minimum attenuation at the amplifier input on an OLT is less than the minimum PSD, APC marks the channel as failed and replaces the channel using ASE source. The default minimum PSD is –24 dBm/12.5 GHz. Use the psd-min command to set the desired minimum PSD.

Use the following commands to set the desired minimum PSD.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

psd-min value

commit

end

The following is a sample configuration that sets the minimum PSD to –25 dBm/12.5 GHz.


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
RP/0/RP0/CPU0:ios(config-olc-ots)#psd-min -250
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
Tue Apr 26 09:50:12.055 UTC
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Configure APC Alarm Hold-off Timer

You can configure an interval before APC-TARGET-PSD-NOT-MET alarm is raised after APC detects a discrepancy. The default value is 90 seconds. Use the following commands to configure the timer.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

apc-alarm-hold-off-timertime

commit

end

The following is a sample configuration that sets the APC alarm hold-off timer to 45 seconds.


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
RP/0/RP0/CPU0:ios(config-olc-ots)#apc-alarm-hold-off-timer 45
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
Tue Apr 26 09:50:12.055 UTC
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Configure APC Alarm Discrepancy Threshold

You can configure the discrepancy allowed before APC-TARGET-PSD-NOT-MET alarm is raised. The default value is 1dB. Use the following commands to configure the threshold.

configure

optical-line-control

controller ots Rack/Slot/Instance/Port

apc-alarm-discrepancy-threshold discrepancy

commit

end

The following is a sample configuration that sets the APC alarm discrepancy threshold to 1.5 dB.


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
RP/0/RP0/CPU0:ios(config-olc-ots)#apc-alarm-discrepancy-threshold 15
RP/0/RP0/CPU0:ios(config-olc-ots)#commit
Tue Apr 26 09:50:12.055 UTC
RP/0/RP0/CPU0:ios(config-olc-ots)#end

Switch Between APC Modes

Switch from Centralized APC to Span Mode APC

Configure APC in manual mode on OLT nodes.
Configure apc-span-mode on all nodes.
Initiate ALC and wait for ALC process to complete.

After ALC baseline is saved, APC switches to span mode.

Switch from Span Mode APC to Centralized APC

You can switch from span-mode APC to centralized APC in two different ways.

Commit replace
1. Reset all nodes to default configuration using the commit replace command.
2. Reload all nodes.
3. Configure the nodes with required configuration for link bring up.
4. Configure automatic link bringup or enable APC.
  
  APC starts regulation in centralized mode.
no configuration of optical applications
1. Remove the optical applications cobnfigurations using the no form of APC, Link Tuner, and Gain estimator.
2. Configure the nodes with required configuration for link bring up.
3. Configure automatic link bringup or enable APC.
  
  APC starts regulation in centralized mode.

Bias-Free Language

Book Title

Cisco NCS 1020 Optical Applications Configuration Guide, IOS XR Release 24.3.x

Chapter Title

Automatic Power Control

Results

Chapter: Automatic Power Control

Automatic Power Control

Overview of Automatic Power Control

View APC Status and Information

Configure APC

Disable APC

Enable Centralized APC

Pause CentralizedAPC

Disable Centralized APC on an ILA Node

Configure Target Drop PSD

Configure Minimum PSD

Configure APC Alarm Hold-off Timer

Configure APC Alarm Discrepancy Threshold

Switch Between APC Modes

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