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Author Topic: Testing the physical status of a cable connected to a dell switch  (Read 5362 times)

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sanjaym

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Link down issue can be very annoying for an admin whether it is a network admin or system admin. There can be many reasons for the
link to be down, One of the main reason is the fault on the cable itself. We can check the fault on a cable by the TDR(Time-Domain
Reflectometry)command. Time-domain reflectometry can be used to locate faults in metallic cables. TDR is useful for troubleshooting an interface that is not establishing a link; either it is flapping or not coming up at all. TDR detects open or short conditions of copper cables on 100/1000 Base-T modules. So lets look at the command,

```
console#test copper-port tdr 2/g18

Cable Status................................... Short
Cable Length................................... 0m

```

The syntax of the command is simple and easy to understand.

test copper-port <interface name> ; the interface name is the port that we want the test to be run.

Based on the cable status the below results will be obtained.

--
No Cable — There is not a cable connected to the port.
Open Cable — The cable is open (nothing on the end).
Short Cable — A short has occurred in the cable.
OK — The cable passed the test.
Fiber Cable — A fiber cable is connected to the port.
Cross Talk — NEXT detected on the cable
--
As you can see the status obtained by running the above command is 'Short' the cable can be inspected for the occurrence of a short circuit.

The list of all interface and cable status obtained previously by performing the test can be seen from the following command,

```
console#show copper-ports tdr
```

The command will also list the type of cable whether a copper or optical fiber cable is connected to the port.

Note : Because TDR is an intrusive test on an interface that is not establishing a link, do not run      TDR on an interface that is passing traffic.