Performing External Loopback Tests - Cisco AP776A - Nexus Converged Network Switch 5020 Configuration Manual

Chapter 59 Monitoring System Processes and Logs
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Internal loopback test on interface iscsi8/1 was
Sent 1 received 1 frames
Round trip time taken is 79 useconds
If the test fails to complete successfully, the software analyzes the failure and prints the following error:
Note
External loopback test on interface fc 7/2 failed. Failure reason: Failed to loopback,
analysis complete Failed device ID 3 on module 1

Performing External Loopback Tests

You can run manual loopback tests to identify hardware errors in the data path in the switching or
services modules, and the control path in the supervisor modules. External loopback tests send and
receive FC2 frames to/from the same port or between two ports.
You need to connect a cable (or a plug) to loop the Rx port to the Tx port before running the test. If you
are testing to/from the same port, you need a special loop cable. If you are testing to/from different ports,
you can use a regular cable. This test is only available for Fibre Channel interfaces.
Use the EXEC-level system health external-loopback interface interface command to run this test on
demand for external devices connected to a switch that is part of a long-haul network.
switch# system health external-loopback interface fc 3/1
This will shut the requested interfaces Do you want to continue (y/n)?
External loopback test on interface fc3/1 was
Sent 1 received 1 frames
Use the EXEC-level system health external-loopback source interface destination interface interface
command to run this test on demand between two ports on the switch.
switch# system health external-loopback source interface fc 3/1 destination interface fc
3/2
This will shut the requested interfaces Do you want to continue (y/n)?
External loopback test on interface fc3/1 and interface fc3/2 was
Sent 1 received 1 frames
Use the EXEC-level system health external-loopback interface frame-count command to run this test
on demand for external devices connected to a switch that is part of a long-haul network and override
the frame count configured on the switch.
switch# system health external-loopback interface fc 3/1 frame-count 10
This will shut the requested interfaces Do you want to continue (y/n)?
External loopback test on interface fc3/1 was
Sent 1 received 1 frames
Use the EXEC-level system health external-loopback interface frame-length command to run this test
on demand for external devices connected to a switch that is part of a long-haul network and override
the frame length configured on the switch.
switch# system health external-loopback interface fc 3/1 frame-length 64
This will shut the requested interfaces Do you want to continue (y/n)?
External loopback test on interface fc3/1 was
Sent 1 received 1 frames
Use the system health external-loopback interface force command to shut down the required interface
directly without a back out confirmation.
switch# system health external-loopback interface fc 3/1 force
External loopback test on interface fc3/1 was
Sent 1 received 1 frames
OL-18084-01, Cisco MDS NX-OS Release 4.x
Online System Health Management
successful.
successful.
successful.
successful.
successful.
successful.
Cisco MDS 9000 Family CLI Configuration Guide
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