Configuration Guide for Cisco NCS 1004, IOS XR Release 25.x.x

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Configuration Guide for Cisco NCS 1004, IOS XR Release 25.x.x

Loopback

Updated: July 31, 2026

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This section explains the loopback features supported on Cisco NCS 1004 controllers and describes the supported cards and their capabilities.

A loopback feature is a diagnostic mechanism that

  • enables you to direct traffic back to its source on specific controller types,

  • helps you identify and troubleshoot connection problems, and

  • can only be configured when the controller is in maintenance mode.

Feature history

Table 1. Feature History

Feature Name

Release Information

Description

Configuration Alarms for Loopback

 Cisco IOS XR Release 7.8.1

A configuration alarm is now triggered whenever there is a change in the loopback configuration. This alarm helps in improving loopback status monitoring.

You can now view the alarm details such as, the configuration time and date, description, severity, and location using the show alarms brief system active command.

You can configure the loopback on the CoherentDSP, FC, OTU, and Ethernet controllers to identify connection problems. The loopback can be configured only in the maintenance mode. Use the controller controller-type and the secondary-admin-state maintenance commands to place the controllers in the maintenance mode.

From Release 7.8.1, loopback configuration alarm details for each controller are triggered whenever there is a change in the loopback configuration. Details such as, location of the controller, severity, configuration date and time, and description are available in the output of the show alarms brief system active and show alarms brief history commands.

Note
Internal and line loopbacks are supported on the FC, OTU, and Ethernet controllers whereas only internal loopbacks are supported on the CoherentDSP controllers.

Configure loopback on the 1.2T and 1.2TL card

Set up a loopback mode for troubleshooting or validation on the 1.2T or 1.2TL line card controllers.

Before you begin

Place the controller in maintenance mode before configuring loopback.

Follow these steps to configure and verify loopback on the selected controller:

Procedure

1.

Run the configure controllercontrollertype Rack/Slot/Instance/Portsec-admin-state maintenance loopback [ line | internal ] to configuring Loopback on the 1.2T Card.

Example:

This example shows how a line loopback is configured on the Ethernet controller. 


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller HundredGigECtrlr 1/0/1/10 secondary-admin-state maintenance
RP/0/RP0/CPU0:ios(config)#commit
Fri Feb 22 19:49:46.504 UTC
RP/0/RP0/CPU0:ios(config)#exit
2.

Run the show controllers command to verify the line loopback configured on the controller.

Example:

This example shows how to verify a line loopback configured on the Ethernet controller. 


RP/0/RP0/CPU0:ios#show controller HundredGigECtrlr 0/1/0/10
Fri Feb 22 19:50:08.328 UTC
Operational data for interface HundredGigECtrlr0/1/0/10:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: Pending
      Total Duration: 0 hour(s) 30 minute(s)
      Remaining Duration: 0 hour(s) 30 minute(s) 0 second(s)
    Laser Squelch: Enabled

Phy:
    Media type: Not known
    Statistics:
        FEC:
            Corrected Codeword Count: 0
            Uncorrected Codeword Count: 0

Autonegotiation disabled.

Operational values:
    Speed: 100Gbps
    Duplex: Full Duplex
    Flowcontrol: None
    Loopback: None (or external)
    BER monitoring:
        Not supported
    Forward error correction: Standard (Reed-Solomon)
    Holdoff Time: 0ms
RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller HundredGigECtrlr 0/1/0/10 loopback line
RP/0/RP0/CPU0:ios(config)#commit
RP/0/RP0/CPU0:ios(config)#exit
RP/0/RP0/CPU0:ios#show controller HundredGigECtrlr 0/1/0/10
Fri Feb 22 20:01:00.521 UTC
Operational data for interface HundredGigECtrlr0/1/0/10:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: Pending
      Total Duration: 0 hour(s) 30 minute(s)
      Remaining Duration: 0 hour(s) 30 minute(s) 0 second(s)
    Laser Squelch: Enabled

Phy:
    Media type: Not known
    Statistics:
        FEC:
            Corrected Codeword Count: 0
            Uncorrected Codeword Count: 6

Autonegotiation disabled.

Operational values:
    Speed: 100Gbps
    Duplex: Full Duplex
    Flowcontrol: None
    Loopback: Line
    BER monitoring:
        Not supported
    Forward error correction: Standard (Reed-Solomon)
    Holdoff Time: 0ms

This example shows how to verify an internal loopback configured on the coherent DSP controller.


RP/0/RP0/CPU0:ios#show controllers coherentDSP  0/0/0/0
Fri Mar 13 22:00:20.951 UTC

Port                                            : CoherentDSP 0/0/0/0
Controller State                                : Up
Inherited Secondary State                       : Normal
Configured Secondary State                      : Maintenance
Derived State                                   : Maintenance
Loopback mode                                   : Internal
BER Thresholds                                  : SF = 1.0E-5  SD = 1.0E-7
Performance Monitoring                          : Enable
Bandwidth                                       : 200.0Gb/s

Alarm Information:
LOS = 0 LOF = 1 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0        SF_BER = 0
SD_BER = 0      BDI = 3 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0
Detected Alarms                                 : None

Bit Error Rate Information
PREFEC  BER                                     : 0.00E+00
POSTFEC BER                                     : 0.00E+00
Q-Factor                                        : 16.70 dB

Q-Margin                                        : 0.99dB

TTI :
        Remote hostname                         : ios
        Remote interface                        : CoherentDSP 0/0/0/0
        Remote IP addr                          : 0.0.0.0

FEC mode                                        : Soft-Decision 27

AINS Soak                                       : None
AINS Timer                                      : 0h, 0m
AINS remaining time                             : 0 seconds

Loopback is configured on the controller.

Configure loopback on the OTN-XP card

Enable loopback testing on OTN-XP card controllers to support diagnostics and troubleshooting.

From Release 7.2.1, OTN-XP card supports loopback on the OTU2, OTU2e, OTU4, 10GE, and CoherentDSP controllers.

From Release 7.3.2, OTN-XP card supports loopback on the 100GE and 400GE controllers.

From Release 7.5.2, OTN-XP card supports loopback on the 16G FC and 32G FC controllers.

The CoherentDSP controller supports both line and internal.

Follow these steps to configure loopback on OTN-XP card controllers:

Procedure

1.

Run the configure controllercontroller type Rack/Slot/Instance/Port/Lane number sec-admin-state maintenance loopback[ line | internal ] to configure the loopback on the controllers.

The range of Lane number is 1–4.

Note

From Release 7.10.1, OTN-XP card supports loopback on STM64 and OC192 controllers. You must use no sec-admin-state command instead of sec-admin-state normal.

Example:

This example shows how an internal loopback is configured on the 10GE controller. 


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller tenGigECtrlr 0/0/0/5/2
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback internal 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#commit

This example shows how a line loopback is configured on the OTU2e controller.


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller otu2e 0/0/0/11/3 
RP/0/RP0/CPU0:ios(config-otu2e)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-otu2e)#loopback line
RP/0/RP0/CPU0:ios(config-otu2e)#commit
Thu Apr 23 10:55:19.319 UTC
RP/0/RP0/CPU0:ios(config-otu2e)#end
This example shows how an internal loopback is configured on the OTU2 controller. 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller otu2 0/0/0/5/1
RP/0/RP0/CPU0:ios(config-otu2)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-otu2)#loopback internal
RP/0/RP0/CPU0:ios(config-otu2)#commit
Thu Apr 23 11:01:00.562 UTC
RP/0/RP0/CPU0:ios(config-otu2)#end
This example shows how an internal loopback is configured on the OTU4 controller. 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller otu4 0/0/0/0
RP/0/RP0/CPU0:ios(config-otu4)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-otu4)#loopback internal 
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Apr 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end

Example:

This example shows how an internal loopback is configured on the 16G FC controller.


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller SixteenGigFibreChanCtrlr 0/2/0/1/1
RP/0/RP0/CPU0:ios(config-SixteenGigFibreChanCtrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-SixteenGigFibreChanCtrlr)#loopback internal 
RP/0/RP0/CPU0:ios(config-SixteenGigFibreChanCtrlr)#commit
Thu Apr 11 10:05:21.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end

This example shows how an internal loopback is configured on the 32G FC controller.


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller ThirtyTwoGigFibreChanCtrlr 0/1/0/6/4
RP/0/RP0/CPU0:ios(config-ThirtyTwoGigFibreChanCtrlr)#loopback internal

RP/0/RP0/CPU0:ios(config-ThirtyTwoGigFibreChanCtrlr)#commit

Sat Apr  9 22:50:11.666 UTC
RP/0/RP0/CPU0:ios(config-ThirtyTwoGigFibreChanCtrlr)#end

Example:

This example shows how the client internal loopback is configured in the 4X100G MXP on 100GE controller.

This example shows how the client internal loopback is configured on the 100GE controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller HundredGigECtrlr 0/2/0/1 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback internal 
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end
This example shows how the client line loopback is configured on the 100GE controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller HundredGigECtrlr 0/2/0/1 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback line    
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end
This example shows how the trunk internal is configured on the coherentDSP controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller coherentDSP 0/2/0/11
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback internal 
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end
This example shows how the trunk line is configured on the coherentDSP controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller coherentDSP 0/2/0/11 
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback line    
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end

This example shows how the client internal loopback is configured in 400G-TXP on 400GE controller.

This example shows how the client internal loopback is configured on the 400GE controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller FourHundredGigECtrlr 0/2/0/10 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback internal 
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end
This example shows how the client line loopback is configured on the 100GE controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller FourHundredGigECtrlr 0/2/0/10 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback line    
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end
This example shows how the trunk internal is configured on the coherentDSP controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller coherentDSP 0/2/0/10
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback internal 
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end
This example shows how the trunk line is configured on the coherentDSP controller: 

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller coherentDSP 0/2/0/10 
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback line    
RP/0/RP0/CPU0:ios(config-otu4)#commit
Thu Sep 23 11:05:22.429 UTC
RP/0/RP0/CPU0:ios(config-otu4)#end
2.

Run the show controllers command to verify the line loopback configured on the controllers.

Example:

This example shows how to verify an internal loopback configured on the 10GE controller. 

RP/0/RP0/CPU0:ios#show controllers tenGigECtrlr 0/0/0/5/2
Thu Apr 23 10:47:48.020 UTC
Operational data for interface TenGigECtrlr0/0/0/5/2:
State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    Laser Squelch: Disabled
Phy:
    Media type: Not known
Autonegotiation disabled.
Operational values:
    Speed: 10Gbps
    Duplex: Full Duplex
    Flowcontrol: None
    Loopback: Internal
    Inter-packet gap: standard (12)
    BER monitoring:
        Not supported
    Holdoff Time: 0ms
This example shows how to verify a line loopback configured on the OTU2e controller. 

RP/0/RP0/CPU0:ios#show controllers otu2e 0/0/0/11/3 
Thu Apr 23 10:55:28.014 UTC

Port                                            : OTU2E 0/0/0/11/3
Controller State                                : Up
Inherited Secondary State                       : Normal
Configured Secondary State                      : Maintenance
Derived State                                   : Maintenance
Loopback mode                                   : Line
BER Thresholds                                  : SF = 1.0E-5  SD = 1.0E-7
Performance Monitoring                          : Enable
Bandwidth                                       : 10.0Gb/s

Alarm Information:
LOS = 0 LOF = 1 LOM = 0
OOF = 1 OOM = 1 AIS = 0
IAE = 0 BIAE = 0        SF_BER = 0
SD_BER = 0      BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0     
Detected Alarms                                 : None

Bit Error Rate Information
PREFEC  BER                                     : 0.00E+00 
POSTFEC BER                                     : 0.00E+00 

TTI :
        Remote hostname                         : ios
        Remote interface                        : OTU2E 0/0/0/11/3
        Remote IP addr                          : 0.0.0.0

FEC mode                                        : STANDARD

AINS Soak                                       : None
AINS Timer                                      : 0h, 0m
AINS remaining time                             : 0 seconds
This example shows how to verify an internal loopback configured on the OTU2 controller. 

RP/0/RP0/CPU0:ios#show controllers otU2 0/0/0/5/1
Thu Apr 23 11:01:04.126 UTC

Port                                            : OTU2 0/0/0/5/1
Controller State                                : Up
Inherited Secondary State                       : Normal
Configured Secondary State                      : Maintenance
Derived State                                   : Maintenance
Loopback mode                                   : Internal
BER Thresholds                                  : SF = 1.0E-5  SD = 1.0E-7
Performance Monitoring                          : Enable
Bandwidth                                       : 10.0Gb/s

Alarm Information:
LOS = 0 LOF = 0 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0        SF_BER = 0
SD_BER = 0      BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0     
Detected Alarms                                 : None

Bit Error Rate Information
PREFEC  BER                                     : 0.00E+00 
POSTFEC BER                                     : 0.00E+00 

TTI :
        Remote hostname                         : SM-TRC SAPI-SECSM-TRC DA
        Remote IP addr                          : 209.165.200.229

FEC mode                                        : STANDARD

AINS Soak                                       : None
AINS Timer                                      : 0h, 0m
AINS remaining time                             : 0 seconds
This example shows how to verify an internal loopback configured on the OTU4 controller. 

RP/0/RP0/CPU0:ios#show controllers otu4 0/0/0/0
Thu Apr 23 11:05:30.281 UTC

Port                                            : OTU4 0/0/0/0
Controller State                                : Up
Inherited Secondary State                       : Normal
Configured Secondary State                      : Maintenance
Derived State                                   : Maintenance
Loopback mode                                   : Internal
BER Thresholds                                  : SF = 1.0E-5  SD = 1.0E-7
Performance Monitoring                          : Enable
Bandwidth                                       : 100.0Gb/s

Alarm Information:
LOS = 1 LOF = 0 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0        SF_BER = 0
SD_BER = 0      BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0     
Detected Alarms                                 : None 

Bit Error Rate Information
PREFEC  BER                                     : 0.00E+00 
POSTFEC BER                                     : 0.00E+00 

TTI :
        Remote hostname                         : ios
        Remote interface                        : OTU4 0/0/0/0
        Remote IP addr                          : 0.0.0.0

FEC mode                                        : STANDARD

AINS Soak                                       : None
AINS Timer                                      : 0h, 0m
AINS remaining time                             : 0 seconds

Example:

This example shows how to verify the internal loopback configured on the 16G FC controller: 

RP/0/RP0/CPU0:ios#show controller SixteenGigFibreChanCtrlr 0/1/0/0/2

Sat Apr  9 22:50:38.930 UTC

Operational data for Fibre Channel controller SixteenGigFibreChanCtrlr0/1/0/0/2

State:
	Admin State           : Up
	Operational state     : Up
	LED state             : Green On
	Secondary admin state : Maintenance
	AINS Soak             : None
	    Total Duration    : 0 hour(s) 0 minute(s)
	    Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
	Laser Squelch         : Disabled

Performance Monitoring is enabled

Operational values:
	Speed                    : 16 Gbps
	Loopback                 : Internal
	BER monitoring:
	    Not supported
	Hold-off Time            : 0 ms
	Forward Error Correction : Not Configured
RP/0/RP0/CPU0:ios#

This example shows how to verify the internal loopback configured on the 32G FC controller:

RP/0/RP0/CPU0:ios#show controller ThirtyTwoGigFibreChanCtrlr 0/1/0/6/4

Sat Apr  9 22:50:39.082 UTC

Operational data for Fibre Channel controller ThirtyTwoGigFibreChanCtrlr0/1/0/6/4

State:
	Admin State           : Up
	Operational state     : Up
	LED state             : Green On
	Secondary admin state : Maintenance
	AINS Soak             : None
	    Total Duration    : 0 hour(s) 0 minute(s)
	    Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
	Laser Squelch         : Disabled

Performance Monitoring is enabled

Operational values:
	Speed                    : 32 Gbps
	Loopback                 : Internal
	BER monitoring:
	    Not supported
	Hold-off Time            : 0 ms
	Forward Error Correction : Standard(Reed Solomon)
RP/0/RP0/CPU0:ios#

Loopback is configured on the OTN-XP card controller. The loopback mode is displayed in the Loopback mode field of the show controllers command output.

Configure loopback on CoherentDSP controllers in inverse muxponder configuration

Enable and verify internal loopback on both trunk ports of the CoherentDSP controllers in inverse muxponder mode to ensure proper configuration and troubleshooting capability.

You can configure loopback on the coherentDSP controllers in the inverse muxponder configuration.

Note
You must configure loopback on both trunk ports 12 and 13, otherwise traffic goes down.

Follow these steps to configure and verify internal loopback on both trunk ports:

Procedure

1.

Run the configure controllercontroller type Rack/Slot/Instance/Port/Lane number sec-admin-state maintenance loopback[ line | internal ]configure loopback on the coherentDSP controllers in the inverse muxponder configuration.

Example:

This example shows how loopback is configured on both the trunk ports.


RP/0/RP0/CPU0:ios#configure
Thu Sep 30 14:16:04.678 UTC
RP/0/RP0/CPU0:ios(config)#controller coherentDSP 0/2/0/12 
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback internal 
RP/0/RP0/CPU0:ios(config-CoDSP)#commit
Thu Sep 30 14:16:19.594 UTC
RP/0/RP0/CPU0:ios(config-CoDSP)#controller coherentDSP 0/2/0/13   
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback internal 
RP/0/RP0/CPU0:ios(config-CoDSP)#commit
Thu Sep 30 14:16:32.390 UTC
RP/0/RP0/CPU0:ios(config-CoDSP)#
2.

Run the show controllers command to verify the configuration.

Example:

This examples shows how to verify loopback configured on the OTN-XP card in the inverse muxponder configuration.


RP/0/RP0/CPU0:ios#show controllers coherentDSP 0/2/0/12 
Thu Sep 30 14:17:04.411 UTC
Port                                            : CoherentDSP 0/2/0/12
Controller State                                : Up
Inherited Secondary State                       : Normal
Configured Secondary State                      : Maintenance
Derived State                                   : Maintenance
Loopback mode                                   : Internal
BER Thresholds                                  : SF = 1.0E-5  SD = 1.0E-7
Performance Monitoring                          : Enable
Bandwidth                                       : 200.0Gb/s
Alarm Information:
LOS = 2 LOF = 0 LOM = 0
OOF = 1 OOM = 0 AIS = 1
IAE = 0 BIAE = 0        SF_BER = 0
SD_BER = 0      BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0     FLEXO_GIDM = 0
FLEXO-MM = 0    FLEXO-LOM = 0   FLEXO-RDI = 1
FLEXO-LOF = 0   
Detected Alarms                                 : None
Bit Error Rate Information
PREFEC  BER                                     : 2.46E-08 
POSTFEC BER                                     : 0.00E+00 
Q-Factor                                        : 14.60 dB 
Q-Margin                                        : 8.30dB 
TTI :
        Remote hostname                         : ios
        Remote interface                        : CoherentDSP 0/2/0/12
        Remote IP addr                          : 0.0.0.0
FEC mode                                        : O_FEC
Flexo-Mode                                      : Enable
Flexo Details:
        Tx GID                                  : 1
        TX IID                                  : 1, 2, 
        Rx GID                                  : 1
        RX IID                                  : 1, 2, 
Flexo Peers Information:
        Controller                              : CoherentDSP0_2_0_13 
        OTUCn rate                              : OTUC2
AINS Soak                                       : None
AINS Timer                                      : 0h, 0m
AINS remaining time                             : 0 seconds
RP/0/RP0/CPU0:ios#sh controllers coherentDSP 0/2/0/13 
Thu Sep 30 14:17:08.140 UTC
Port                                            : CoherentDSP 0/2/0/13
Controller State                                : Up
Inherited Secondary State                       : Normal
Configured Secondary State                      : Maintenance
Derived State                                   : Maintenance
Loopback mode                                   : Internal
BER Thresholds                                  : SF = 1.0E-5  SD = 1.0E-7
Performance Monitoring                          : Enable
Bandwidth                                       : 200.0Gb/s
Alarm Information:
LOS = 1 LOF = 0 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0        SF_BER = 0
SD_BER = 0      BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0     FLEXO_GIDM = 0
FLEXO-MM = 0    FLEXO-LOM = 0   FLEXO-RDI = 1
FLEXO-LOF = 0   
Detected Alarms                                 : None
Bit Error Rate Information
PREFEC  BER                                     : 0.00E+00 
POSTFEC BER                                     : 0.00E+00 
Q-Factor                                        : 15.70 dB 

Q-Margin                                        : 9.50dB 

TTI :
        Remote IP addr                          : 0.0.0.0
FEC mode                                        : O_FEC
Flexo-Mode                                      : Enable
Flexo Details:
        Tx GID                                  : 1
        TX IID                                  : 3, 4, 
        Rx GID                                  : 1
        RX IID                                  : 3, 4, 

Flexo Peers Information:
        Controller                              : CoherentDSP0_2_0_12 
        OTUCn rate                              : OTUC2
AINS Soak                                       : None
AINS Timer                                      : 0h, 0m
AINS remaining time                             : 0 seconds

Internal loopback is configured on both trunk ports 12 and 13 in the inverse muxponder configuration. The Loopback mode: Internal field confirms the configuration.

Configure loopback on the 2-QDD-C card

Set up and validate loopback modes for troubleshooting and diagnostics on high-speed controllers.
From Release 7.3.1, 2-QDD-C card supports loopback on the 100GE and 400GE controllers.
Note

On applying client-side loopbacks, traffic is looped and does not continue in the 2-QDD-C card. QSFP squelching happens on applying internal loopback.

Follow these steps to configure and verify loopback on the 2-QDD-C card controllers:

Procedure

1.

Run the configure controllercontrollertype Rack/Slot/Instance/Port/Lanenumber sec-admin-state maintenance loopback [ line | internal ] command to configure the loopback on the controllers.

Example:

This example shows how an internal loopback is configured on a 100GE controller. 


RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller hundredGigECtrlr 0/0/0/5
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback internal 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#commit

Example:

From Release 7.5.2, Loopback is supported for the OTUCn-REGEN mode on the coherent DSP controller.

This example shows how to configure an internal loopback on a coherent DSP controller.

Sun Dec 26 14:34:02.733 UTC
RP/0/RP0/CPU0:ios(config)#controller CoherentDSP 0/3/0/12
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance
RP/0/RP0/CPU0:ios(config-CoDSP)#commit
Sun Dec 26 14:34:03.437 UTC
RP/0/RP0/CPU0:ios(config-CoDSP)#end
2.

Run the show controllers command to verify internal loopback configured on the controller.

Example:

This example shows how to verify the internal loopback configured on a 100GE controller.


RP/0/RP0/CPU0:ios#show controllers hundredGigECtrlr 0/0/0/5
Thu Apr 23 10:47:48.020 UTC
Operational data for interface hundredGigECtrlr0/0/0/5:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    Laser Squelch: Disabled

Phy:
    Media type: Not known

Autonegotiation disabled.

Operational values:
    Speed: 10Gbps
    Duplex: Full Duplex
    Flowcontrol: None
    Loopback: Internal
    Inter-packet gap: standard (12)
    BER monitoring:
        Not supported
    Holdoff Time: 0ms

Example:

This example shows how to verify internal loopback configured on a coherent DSP controller.


RP/0/RP0/CPU0:ios#show controller CoherentDSP 0/3/0/12

Sun Dec 26 14:34:28.391 UTC

Port : CoherentDSP 0/3/0/12
Controller State : Up
Inherited Secondary State : Normal
Configured Secondary State : Maintenance
Derived State : Maintenance
Loopback mode : Line
BER Thresholds : SF = 1.0E-5 SD = 1.0E-7
Performance Monitoring : Enable
Bandwidth : 200.0Gb/s

Alarm Information:
LOS = 1 LOF = 0 LOM = 0
OOF = 1 OOM = 0 AIS = 1
IAE = 0 BIAE = 0 SF_BER = 0
SD_BER = 0 BDI = 5 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0 FLEXO_GIDM = 0
FLEXO-MM = 0 FLEXO-LOM = 0 FLEXO-RDI = 0
FLEXO-LOF = 0
Detected Alarms : None

Bit Error Rate Information
PREFEC BER : 3.12E-07
POSTFEC BER : 0.00E+00
Q-Factor : 14.00 dB

Q-Margin : 6.40dB

TTI :
Remote hostname : ios
Remote interface : CoherentDSP 0/2/0/13
Remote IP addr : 0.0.0.0

FEC mode : O_FEC

Flexo-Mode : Enable
Flexo Details:
Tx GID : 1
TX IID : 1, 2,
Rx GID : 1
RX IID : 1, 2,

AINS Soak : None
AINS Timer : 0h, 0m
AINS remaining time : 0 seconds

Loopback is configured on the 2-QDD-C card controller.

Configure loopback on the QXP card

Enable loopback modes on QXP card controllers for testing and diagnostics.
Follow these steps to configure and verify loopback on QXP card controllers:

Procedure

1.

Run the configure controllercontrollertype Rack/Slot/Instance/Port/Lanenumber sec-admin-state maintenance loopback [ line | internal ] command to configure the loopback on the controllers.

Example:

This example shows how to configure internal loopback on a coherent DSP controller.


RP/0/RP0/CPU0:ios#configure
Fri Jul 8 10:42:51.329 UTC
RP/0/RP0/CPU0:ios(config)#controller coherentDSP 0/0/0/0
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback internal
RP/0/RP0/CPU0:ios(config-CoDSP)#commit
Fri Jul 8 10:43:48.644 UTC
RP/0/RP0/CPU0:ios(config-CoDSP)#end
This example shows how to configure line loopback on a coherent DSP controller. 

RP/0/RP0/CPU0:ios#configure
Fri Jul 8 10:48:48.577 UTC
RP/0/RP0/CPU0:ios(config)#controller coherentDSP 0/0/0/0
RP/0/RP0/CPU0:ios(config-CoDSP)#secondary-admin-state maintenance
RP/0/RP0/CPU0:ios(config-CoDSP)#loopback line
RP/0/RP0/CPU0:ios(config-CoDSP)#commit
Fri Jul 8 10:49:26.809 UTC
RP/0/RP0/CPU0:ios(config-CoDSP)#end

This example shows how to verify the line loopback configured on a coherent DSP controller.

RP/0/RP0/CPU0:ios#show controllers coherentDSP 0/0/0/0
Fri Jul 8 10:49:44.073 UTC
Port : CoherentDSP 0/0/0/0
Controller State : Down
Inherited Secondary State : Normal
Configured Secondary State : Maintenance
Derived State : Maintenance
Loopback mode : Line
BER Thresholds : SF = 1.0E-5 SD = 1.0E-7
Performance Monitoring : Enable
Bandwidth : 400.0Gb/s
Alarm Information:
LOS = 2 LOF = 0 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0 SF_BER = 0
SD_BER = 0 BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0 FLEXO_GIDM = 0
FLEXO-MM = 0 FLEXO-LOM = 0 FLEXO-RDI = 0
FLEXO-LOF = 0
Detected Alarms : LOS
Bit Error Rate Information
PREFEC BER : 5.00E-01
POSTFEC BER : 0.00E+00
Q-Factor : 0.00 dB
Q-Margin : 0.00dB
OTU TTI Received
FEC mode : C_FEC
Flexo-Mode : Enable
Flexo Details:
Tx GID : 0
Rx GID : 0
AINS Soak : None
AINS Timer : 0h, 0m
AINS remaining time : 0 seconds

This example shows how to configure line loopback on the 4X100GE MXP.

RP/0/RP0/CPU0:ios(config)#controller hundredGigECtrlr 0/3/0/1/1
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback line 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#commit

This example shows how to configure internal loopback on the 4X100GE MXP.

RP/0/RP0/CPU0:ios#conf
RP/0/RP0/CPU0:ios(config)#controller hundredGigECtrlr 0/3/0/7/1
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#sec-admin-state maintenance 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#loopback internal 
RP/0/RP0/CPU0:ios(config-eth-ctrlr)#commit
2.

Run the show controllers command to verify internal loopback configured on the controller.

Example:

This example shows how to verify the internal loopback configured on a coherent DSP controller.


RP/0/RP0/CPU0:ios#show controllers coherentDSP 0/0/0/0
Fri Jul 8 10:45:53.820 UTC
Port : CoherentDSP 0/0/0/0
Controller State : Down
Inherited Secondary State : Normal
Configured Secondary State : Maintenance
Derived State : Maintenance
Loopback mode : Internal
BER Thresholds : SF = 1.0E-5 SD = 1.0E-7
Performance Monitoring : Enable
Bandwidth : 400.0Gb/s
Alarm Information:
LOS = 2 LOF = 0 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0 SF_BER = 0
SD_BER = 0 BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0 FLEXO_GIDM = 0
FLEXO-MM = 0 FLEXO-LOM = 0 FLEXO-RDI = 0
FLEXO-LOF = 0
Detected Alarms : LOS
Bit Error Rate Information
PREFEC BER : 5.00E-01
POSTFEC BER : 0.00E+00
Q-Factor : 0.00 dB
Q-Margin : 0.00dB
OTU TTI Received
FEC mode : C_FEC
Flexo-Mode : Enable
Flexo Details:
Tx GID : 0
Rx GID : 0
AINS Soak : None
AINS Timer : 0h, 0m
AINS remaining time : 0 seconds

This example shows how to verify the line loopback configured on a coherent DSP controller.


RP/0/RP0/CPU0:ios#show controllers coherentDSP 0/0/0/0
Fri Jul 8 10:49:44.073 UTC
Port : CoherentDSP 0/0/0/0
Controller State : Down
Inherited Secondary State : Normal
Configured Secondary State : Maintenance
Derived State : Maintenance
Loopback mode : Line
BER Thresholds : SF = 1.0E-5 SD = 1.0E-7
Performance Monitoring : Enable
Bandwidth : 400.0Gb/s
Alarm Information:
LOS = 2 LOF = 0 LOM = 0
OOF = 0 OOM = 0 AIS = 0
IAE = 0 BIAE = 0 SF_BER = 0
SD_BER = 0 BDI = 0 TIM = 0
FECMISMATCH = 0 FEC-UNC = 0 FLEXO_GIDM = 0
FLEXO-MM = 0 FLEXO-LOM = 0 FLEXO-RDI = 0
FLEXO-LOF = 0
Detected Alarms : LOS
Bit Error Rate Information
PREFEC BER : 5.00E-01
POSTFEC BER : 0.00E+00
Q-Factor : 0.00 dB
Q-Margin : 0.00dB
OTU TTI Received
FEC mode : C_FEC
Flexo-Mode : Enable
Flexo Details:
Tx GID : 0
Rx GID : 0
AINS Soak : None
AINS Timer : 0h, 0m
AINS remaining time : 0 seconds

This example shows how to verify the internal loopback configured on the 400GE controller.


RP/0/RP0/CPU0:ios#show controllers FourHundredGigECtrlr 0/0/0/3
Fri Jul 8 11:19:59.597 UTC
Operational data for interface FourHundredGigECtrlr0/0/0/3:
State:
Administrative state: enabled
Operational state: Down (Reason: State undefined)
LED state: Red On
Maintenance: Enabled
AINS Soak: None
Total Duration: 0 hour(s) 0 minute(s)
Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
Laser Squelch: Disabled
Insert Idle Ingress: Disabled
Insert Idle Egress: Disabled
Phy:
Media type: Not known
Alarms:
Current:
Loss of Signal
Statistics:
FEC:
Corrected Codeword Count: 702710
Uncorrected Codeword Count: 1147
Autonegotiation disabled.
Operational values:
Speed: 400Gbps
Duplex: Full Duplex
Flowcontrol: None
Loopback: Internal
BER monitoring:
Not supported
Forward error correction: Standard (Reed-Solomon)
Holdoff Time: 0ms

This example shows how to verify the line loopback configured on the 4X100GE MXP.

RP/0/RP0/CPU0:ios#sh controllers hundredGigECtrlr 0/3/0/1/1
Fri Jul 22 10:34:39.730 UTC
Operational data for interface HundredGigECtrlr0/3/0/1/1:

State:
    Administrative state: enabled
    Operational state: Up
    LED state: Green On
    Maintenance: Enabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    Laser Squelch: Disabled
    Insert Idle Ingress: Disabled
    Insert Idle Egress: Disabled

Phy:
    Media type: Not known
    Statistics:
        FEC:
            Corrected Codeword Count: 6110368                  Valid: True       Start time: 13:10:41 Thu Jul 21 2022
            Uncorrected Codeword Count: 2771                   Valid: True       Start time: 13:10:41 Thu Jul 21 2022
        PCS:
            Total BIP errors: 63700992                         Valid: True       Start time: 13:10:41 Thu Jul 21 2022
            Total frame errors: 0                              Valid: False      Start time: 13:10:41 Thu Jul 21 2022
            Total Bad SH: 0                                    Valid: False      Start time: 13:10:41 Thu Jul 21 2022

Autonegotiation disabled.

Operational values:
    Speed: 100Gbps
    Duplex: Full Duplex
    Flowcontrol: None
    Loopback: Line
    BER monitoring:
        Not supported
    Forward error correction: Standard (Reed-Solomon)
    Holdoff Time: 0ms
The following example shows how to verify the internal loopback configured on the 4X100GE MXP.
RP/0/RP0/CPU0:ios#show controller HundredGigECtrlr 0/3/0/7/1
Fri Jul 22 10:40:34.928 UTC

Operational data for interface HundredGigECtrlr0/3/0/7/1:

State:
    Administrative state: enabled
    Operational state: Down (Reason: State undefined)
    LED state: Red On
    Maintenance: Enabled
    AINS Soak: None
      Total Duration: 0 hour(s) 0 minute(s)
      Remaining Duration: 0 hour(s) 0 minute(s) 0 second(s)
    Laser Squelch: Disabled
    Insert Idle Ingress: Disabled
    Insert Idle Egress: Disabled

Phy:
    Media type: Not known
    Alarms:
        Current:
            Loss of Signal
    Statistics:
        FEC:
            Corrected Codeword Count: 31426046
            Uncorrected Codeword Count: 2187

Autonegotiation disabled.

Operational values:
    Speed: 100Gbps
    Duplex: Full Duplex
    Flowcontrol: None
    Loopback: Internal
    BER monitoring:
        Not supported
    Forward error correction: Standard (Reed-Solomon)
    Holdoff Time: 0ms

Loopback mode (line or internal) is configured and verified on the specified controller on the QXP card.

View loopback configuration alarms

Enable monitoring of loopback configuration changes by displaying relevant alarms.
Follow these steps to verify loopback configuration alarms:

Procedure

Run the show alarms brief system active command to view the loopback configuration alarms on the 2-QDD-C, 1.2T, 1.2TL, OTN-XP, and QXP cards.

Example:


RP/0/RP0/CPU0:ios#show alarms brief system active
Tue Sep 13 17:43:35.212 UTC

------------------------------------------------------------------------------------
Active Alarms
------------------------------------------------------------------------------------
Location        Severity     Group            Set Time                   Description                                                                                                                                                                              
------------------------------------------------------------------------------------                                                                                                                                                                                                                                                                                             0/2             Minor        Controller       09/13/2022 17:34:32 UTC    HundredGigECtrlr0/2/0/2 - Internal Loopback Configured
0/2             Minor        Controller       09/13/2022 17:34:32 UTC    HundredGigECtrlr0/2/0/2 - Internal Loopback Configured
0/2             Minor        Controller       09/13/2022 17:34:32 UTC    HundredGigECtrlr0/2/0/8 - Line Loopback Configured                                                                                                                                   
0/2             Major        Ethernet         09/13/2022 17:34:31 UTC    HundredGigECtrlr0/2/0/4 - Loss of Synchronization The Data Interface                                                                                                                     
0/2             Minor        Controller       09/13/2022 17:37:42 UTC    OTU40/2/0/8 - Internal Loopback Configured                                                                                                                                               
0/2             Minor        Controller       09/13/2022 17:39:19 UTC    CoherentDSP0/2/0/0 - Internal Loopback Configured

The show alarms brief system active command displays all active loopback configuration alarms with their location, severity, set time, and description.