Debug Commands; Enabling Debugging On A Specific Feature - Cisco Catalyst 2950 Software Manual

Chapter 14 Troubleshooting
Step 4 Reconnect the power cord to the switch.
The software image does not load. The switch starts in boot loader mode, which is indicated by the
switch:
Use the boot loader to enter commands, and start the transfer.
Step 5
switch: copy xmodem: flash:image_filename.bin
When the XMODEM request appears, use the appropriate command on the terminal-emulation software
Step 6
to start the transfer and to copy the software image to Flash memory.

Debug Commands

This section explains how you use debug commands to diagnose and resolve internetworking problems:
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•
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Because debugging output is assigned high priority in the CPU process, it can render the system
Caution
unusable. For this reason, use debug commands only to troubleshoot specific problems or during
troubleshooting sessions with Cisco technical support staff. It is best to use debug commands during
periods of lower network traffic and fewer users. Debugging during these periods decreases the
likelihood that increased debug command processing overhead will affect system use.

Enabling Debugging on a Specific Feature

All debug commands are entered in privileged EXEC mode, and most debug commands take no
arguments. For example, beginning in privileged EXEC mode, enter this command to enable the
debugging for EtherChannel:
Switch# debug etherchannel
The switch continues to generate output until you enter the no form of the command.
If you enable a debug command and no output appears, consider these possibilities:
•
•
To disable debugging of EtherChannel, enter this command in privileged EXEC mode:
Switch# no debug etherchannel
Alternately, in privileged EXEC mode, you can enter the undebug form of the command:
Switch# undebug etherchannel
78-11380-03
prompt.
Enabling Debugging on a Specific Feature, page 14-11
Enabling All-System Diagnostics, page 14-12
Redirecting Debug and Error Message Output, page 14-12
The switch might not be properly configured to generate the type of traffic you want to monitor. Use
the show running-config command to check its configuration.
Even if the switch is properly configured, it might not generate the type of traffic you want to
monitor during the particular period when debugging is enabled. Depending on the feature you are
debugging, you can use commands such as the TCP/IP ping command to generate network traffic.
Catalyst 2950 Desktop Switch Software Configuration Guide
Debug Commands
14-11