Extreme Networks ExtremeWare 7.2e, Installation And User Manual

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326 ExtremeWare 7.2e Installation and User Guide
Troubleshooting
Cable Diagnostics
If you are having a problem establishing a link, you might have a faulty Ethernet cable. An Ethernet
cable is composed of four pairs of unshielded twisted-pair (UTP). Of those four pairs, two are required
to create the link. In addition to physically inspecting the cable, you can run a CLI command to test the
cable. Use the following commands to test an Ethernet cable and to display the output of the test:
run diagnostics cable ports <portlist>
show ports <portlist> cable diagnostics
The
run diagnostics cable ports
command prompts you when the diagnostics are complete to
enter the
show ports cable diagnostics
command.
By reviewing the output of the
show
command you can determine:
• The length of the cable
• Whether there is a successful termination, or whether there is an open or short
For example, the following command set tests the Ethernet cable inserted into port 1. The four copper
pairs do not all have the same length, which might indicate a kink in the cable, or a open connection:
Summit400-48t:27 # run diagnostics cable ports 1
Cable Diagnostics has completed, to view results enter
show port <port list> cable diagnostics
Summit400-48t:28 # show port 1 cable diagnostics
Port Pair Length Status
1 Pair A 3 meters Terminated
Pair B 2 meters Terminated
Pair C 1 meters Open or Short
Pair D 1 meters Open or Short
The next example shows none of the twisted pairs terminate successfully at port 1, which could indicate
that the cable is not inserted into the port:
Summit400-48t:29 # run diagnostics cable ports 1
Cable Diagnostics has completed, to view results enter
show port <port list> cable diagnostics
Summit400-48t:30 # show port 1 cable diagnostics
Port Pair Length Status
1 Pair A 0 meters Open or Short
Pair B 0 meters Open or Short
Pair C 0 meters Open or Short
Pair D 0 meters Open or Short