Reference Guide

Interfaces | 139

Maintenance Using TDR

The time domain reflectometer (TDR) is supported on all Dell Force10 switch/routers. TDR is an

assistance tool to resolve link issues that helps detect obvious open or short conditions within any of the

four copper pairs. TDR sends a signal onto the physical cable and examines the reflection of the signal that

returns. By examining the reflection, TDR is able to indicate whether there is a cable fault (when the cable

is broken, becomes unterminated, or if a transceiver is unplugged).

TDR is useful for troubleshooting an interface that is not establishing a link, that is, when the link is

flapping or not coming up. Do not use TDR on an interface that is passing traffic. When a TDR test is run

on a physical cable, it is important to shut down the port on the far end of the cable. Otherwise, it may lead

to incorrect test results.

To test the condition of cables on 100/1000/10000 BASE-T modules, following these steps using the

tdr-cable-test command.

Note: TDR is an intrusive test. Do not run TDR on a link that is up and passing traffic.

Step Command Syntax Command Mode Usage

1 tdr-cable-test tengigabitethernet

<slot>/

<port>

EXEC Privilege To test for cable faults on the

TenGigabitEthernet cable.

• Between two ports, you must not start the

test on both ends of the cable.

• Enable the interface before starting the

test.

• The port must be enabled to run the test or

the test prints an error message.

show tdr tengigabitethernet <slot>/<port> EXEC Privilege Displays TDR test results.