Using Tdr; Understanding Tdr; Running Tdr And Displaying The Results; Using Debug Commands - Cisco Catalyst 2928 Software Configuration Manual

Using TDR

Using TDR
These sections contain this information:
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Understanding TDR

You can use the Time Domain Reflector (TDR) feature to diagnose and resolve cabling problems. When
running TDR, a local device sends a signal through a cable and compares the reflected signal to the initial
signal.
TDR is supported only on 10/100 and 10/100/1000 copper Ethernet ports. It is not supported on SFP
module ports.
TDR can detect these cabling problems:
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If one of the twisted-pair wires is open, TDR can find the length at which the wire is open.
Use TDR to diagnose and resolve cabling problems in these situations:
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Running TDR and Displaying the Results

To run TDR, enter the test cable-diagnostics tdr interface interface-id privileged EXEC command:
To display the results, enter the show cable-diagnostics tdr interface interface-id privileged EXEC
command. For a description of the fields in the display, see the command reference for this release.

Using Debug Commands

These sections explains how you use debug commands to diagnose and resolve internetworking
problems:
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Catalyst 2928 Switch Software Configuration Guide
33-18
Understanding TDR, page 33-18
Running TDR and Displaying the Results, page 33-18
Open, broken, or cut twisted-pair wires—The wires are not connected to the wires from the remote
device.
Shorted twisted-pair wires—The wires are touching each other or the wires from the remote device.
For example, a shorted twisted pair can occur if one wire of the twisted pair is soldered to the other
wire.
Replacing a switch
Setting up a wiring closet
Troubleshooting a connection between two devices when a link cannot be established or when it is
not operating properly
Enabling Debugging on a Specific Feature, page 33-19
Enabling All-System Diagnostics, page 33-19
Redirecting Debug and Error Message Output, page 33-20
Chapter 33 Troubleshooting
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