CLI Reference Guide

Chapter 11 | Interface Commands
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◆ The test takes approximately 1 second. Use the show cable-diagnostics
command to display the results of the test, including common cable failures, as
well as the status and approximate length of each cable pair.
◆ Potential conditions which may be listed by the diagnostics include those listed
below.
■
Pair busy, linked partner in 100BAS-TX forced mode
■
Interpair short
■
Intrapair short
■
Pair open, fault detected
■
Invalid, cable diagnostic routine did not complete successfully
◆ Ports must have auto-negotiation enabled
◆ Ports are linked down while running cable diagnostics.
◆ This cable test is only accurate for Ethernet cables 7 - 100 meters long.
◆ Ports are linked down while running cable diagnostics.
◆ To ensure more accurate measurement of the length to a fault, first disable
power-saving mode (using the no power-save command) on the link partner
before running cable diagnostics.
Example
Console#test cable-diagnostics interface ethernet 1/21
Cable Diagnostics on interface Ethernet 1/21:
Cable OK with accuracy 10 meters.
Pair A OK, length 0 meters
Pair B OK, length 0 meters
Pair C OK, length 7 meters
Pair D Open, length 2 meters
Last Update 0n 2019-05-31 09:16:57
Console#
test loop internal
test loop internal This command performs an internal loop back test on the specified port.
Syntax
test loop internal interface interface
interface
ethernet unit/port
unit - Unit identifier. (Range: 1)
port - Port number. (1-54)