When applying a top-down approach towards troubleshooting a networking
problem, the end user application is examined first. Then work down from the
upper-layers of the OSI model until the cause of the problem has been
identified.
When a
troubleshooter selects this approach, the applications of an end system are
tested before tackling the more specific networking pieces. A troubleshooter
would most likely select this approach for simpler problems or when the
troubleshooter thinks that the problem is with a piece of software.
The
disadvantage to selecting this approach is that it requires checking of every
network application until the possible cause of the problem is found. It is a
requirement to document each conclusion and possibility. Like the bottom-up
approach, the challenge is to determine which application to start with.