Use this task to configure loopback for controller validation and troubleshooting.
You can configure internal or line loopback on coherent DSP controllers. You can configure media loopback and host loopback on optics controllers.
Loopback can be performed only in maintenance mode.
Use the loopback and host loopback commands in optics controller configuration mode to configure the media and host loopback modes. Loopback mode for both media and host can be configured to either internal or line, depending on the supported loopback types.
Note
Line loopback mode is supported only on Cisco 8000 Series line cards and fixed-port routers based on Q100 and Q200 silicon.
Before you begin
Identify the controller R/S/I/P and the loopback mode that you want to configure.
Procedure
-
Check the supported loopback types for the optics controller.
Example:
Use the show controllers optics R/S/I/P information loopback command to check the supported loopback types.
Router#show controllers optics 0/0/0/4 information loopback
Supported Loopback Types :
============================
[1.] Media Line
[2.] Host Internal
Unsupported Loopback Types :
=============================
[1.] Media Internal
[2.] Host Line
[3.] Host Per Lane
[4.] Media Per Lane
[5.] Simultaneous Media Host
Media Configured Loopback : Media Loopback None
Media Applied Loopback : Media Loopback None
Host Configured Loopback : Host Loopback None
Host Applied Loopback : Host Loopback None
-
Configure internal loopback on a coherent DSP controller.
Example:
Router#config
Router(config)#controller coherentDSP 0/0/0/4
Router(config-CoDSP)#secondary-admin-state maintenance
Router(config-CoDSP)#loopback internal
Router(config-CoDSP)#commit
-
Configure media loopback and host loopback on an optics controller.
Example:
Router#config
Router(config)#controller optics 0/0/0/4
Router(config-Optics)#sec-admin-state maintenance
Router(config-Optics)#loopback line /* configures the media loopback to line */
Router(config-Optics)#host loopback internal /* configures the host loopback to internal */
Router(config-Optics)#commit
-
Verify the running configuration on the coherent DSP controller.
Example:
Router#show run controller coherentdsp 0/0/0/4
Thu May 13 19:51:08.175 UTC
controller CoherentDSP0/0/0/4
secondary-admin-state maintenance
loopback internal
!
-
Verify the running configuration on the optics controller.
Example:
Router#show run controller optics 0/0/0/4
Thu May 13 19:51:08.175 UTC
controller Optics0/0/0/4
loopback line
host loopback internal
sec-admin-state maintenance
!
-
Verify the loopback configuration on the coherent DSP controller.
Example:
Router#show controller coherentdsp 0/0/0/4
Thu May 27 17:28:51.960 UTC
Port : CoherentDSP 0/0/0/4
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 = 6 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 = 5
Detected Alarms : LOS
Bit Error Rate Information
PREFEC BER : 5.0E-01
POSTFEC BER : 0.0E+00
Q-Factor : 0.00 dB
Q-Margin : -7.20dB
OTU TTI Received
FEC mode : C_FEC
-
Verify the loopback configuration on the optics controller.
Example:
Router#show controllers optics 0/0/0/4
Controller State: Up
Transport Admin State: In Service
Laser State: On
Host Squelch Status: Enable
Media linkdown preFEC degrade : Disabled
LED State: Yellow
FEC State: FEC ENABLED
Power Mode: High
Dom Data Status: Ready
Last link flapped: 00:02:32
Optics Status
Optics Type: QSFPDD 400G ZR
DWDM carrier Info: C BAND, MSA ITU Channel=1, Frequency=196.10THz,
Wavelength=1528.773nm
Loopback Host : Internal
Loopback Media : Line
Alarm Status:
-------------
Detected Alarms: None
LOS/LOL/Fault Status:
...
-
Verify the configured and applied loopback states on the optics controller.
Example:
Router#show controllers optics 0/0/0/4 information loopback
Supported Loopback Types :
============================
[1.] Media Line
[2.] Host Internal
Unsupported Loopback Types :
=============================
[1.] Media Internal
[2.] Host Line
[3.] Host Per Lane
[4.] Media Per Lane
[5.] Simultaneous Media Host
Media Configured Loopback : Media Loopback Line
Media Applied Loopback : Media Loopback Line
Host Configured Loopback : Host Loopback Internal
Host Applied Loopback : Host Loopback Internal
Loopback is configured in maintenance mode, and the controller output shows the configured and applied loopback states.
What to do next
Remove or change the loopback configuration when validation or troubleshooting is complete.