Approaches to troubleshooting:

• Top-Down
• Bottom-Up
• Divide-and-conquer
• Follow the Path

• Spot the Difference - configuration comparison
• Swapping Components

Cisco's Structured Troubleshooting Model:

• Define the Problem
• Collect Information
• Analyze the information
• Eliminate Potential Causes
• Propose a Hypothesis
• Test Hypothesis

Solve and Document