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Catalyst 2975 Switch Software Configuration Guide
OL-19720-02
Chapter 38 Troubleshooting
Using TDR
Using TDR
These sections contain this information:
•
•
Running TDR and Displaying the Results, page 38-19
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 10/100/1000 copper Ethernet ports. It is not supported on SFP module ports.
TDR can detect these cabling problems:
•
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.
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:
•
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
Running TDR and Displaying the Results
When you run TDR on an interface, you can run it on the stack master or a stack member.
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:
•
Enabling Debugging on a Specific Feature, page 38-20
•
Enabling All-System Diagnostics, page 38-20
•
Содержание 2975 - Catalyst LAN Base Switch
Страница 36: ...Contents xxxvi Catalyst 2975 Switch Software Configuration Guide OL 19720 02 ...
Страница 40: ...xxxviii Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Preface ...
Страница 62: ...1 22 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 1 Overview Where to Go Next ...
Страница 398: ...13 30 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 13 Configuring VLANs Configuring VMPS ...
Страница 424: ...15 18 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 15 Configuring VTP Monitoring VTP ...
Страница 628: ...26 8 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 26 Configuring UDLD Displaying UDLD Status ...
Страница 660: ...28 8 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 28 Configuring RMON Displaying RMON Status ...
Страница 888: ...38 32 Catalyst 2975 Switch Software Configuration Guide OL 19720 02 Chapter 38 Troubleshooting Troubleshooting Tables ...