Troubleshooting Methodologies

A troubleshooting methodology is a structured approach to diagnosing network problems that prevents guesswork and reduces time to resolution. The most common approaches are bottom-up (starting at the Physical layer and working up through the OSI model), top-down (starting at the Application layer and working down), and divide and conquer (starting at a middle layer based on available evidence). Most methodologies follow a general cycle: identify the problem, establish a theory of probable cause, test the theory, create a plan of action, implement the fix, verify full functionality, and document the outcome.