Spot-the-difference approach: the malfunctioning parts or sections are compared to similar areas. The differences are eliminated slowly until the issue is resolved, which helps identify the problem.
Move-the-problem approach: the components that may be causing the issues are moved or replaced. This helps identify the problematic elements and narrow down the problem.
Follow-the-path approach: the path the data packets are moving in is followed to see where the issue occurs.
OSI model-based approach: the problem is approached through the OSI model, either top to bottom or bottom-up. The different OSI layers are checked to narrow down the issue.