Cisco 3845 Software Guide - Page 854

Using TDR Chapter 35 Troubleshooting To end a trace in progress, enter the escape sequence (Ctrl-^ X by default). Simultaneously press and release the Ctrl, Shift, and 6 keys, and then press the X key. Using TDR • Understanding TDR, page 12 • Running TDR and Displaying the Results, page 12 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 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 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. Note ITDR is supported only on the copper Ethernet 10/100/1000 ports. Using Debug Commands • Enabling Debugging on a Specific Feature, page 13 • Enabling All-System Diagnostics, page 13 • Redirecting Debug and Error Message Output, page 14 35-12 Cisco ME 3800X and 3600X Switch Software Configuration Guide OL-23400-01