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CHAPTER
31-1
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
31
Troubleshooting
This chapter describes how to identify and resolve Catalyst 2950 and Catalyst 2955 software problems
related to the Cisco IOS software. Depending on the nature of the problem, you can use the
command-line interface (CLI), the device manager, or to identify and solve problems. To identify and
resolve Cisco Course Wave Division Multiplexer (CWDM) Gigabit Interface Converter (GBIC)
problems, you must have the enhanced software image (EI) installed on your non-Long-Reach Ethernet
(LRE) Catalyst 2950 switch.
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release and the Cisco IOS Command Summary for Cisco IOS Release 12.1.
This chapter consists of these sections:
• Using Recovery Procedures, page 31-1
• Preventing Autonegotiation Mismatches, page 31-13
• GBIC and SFP Module Security and Identification, page 31-14
• Diagnosing Connectivity Problems, page 31-14
• Diagnosing LRE Connection Problems, page 31-17
• Using Debug Commands, page 31-18
• Using the show controllers Commands, page 31-21
• Using the crashinfo File, page 31-21
Using Recovery Procedures
These recovery procedures require that you have physical access to the switch:
• Recovering from a Software Failure, page 31-2
• Recovering from Lost or Forgotten Passwords on Non-LRE Catalyst 2950 Switches, page 31-2
• Recovering from Lost or Forgotten Passwords on Catalyst 2950 LRE Switches, page 31-4
• Recovering from Lost or Forgotten Passwords on Catalyst 2955 Switches, page 31-7
• Recovering from a Command Switch Failure, page 31-10
• Recovering from Lost Member Connectivity, page 31-13