The stages of the general troubleshooting process are:
| Step 1 | Gather symptoms |
| Step 2 | Isolate the problem |
| Step 3 | Correct the problem |
The stages are not mutually exclusive. At any point in the process,
it may be necessary to retrace to previous steps. For instance, it may be
required to gather more symptoms while isolating a problem. Additionally, when
attempting to correct a problem, another unidentified problem could be created.
As a result, it would be necessary to gather the symptoms, isolate, and correct
the new problem.

A
troubleshooting policy should be established for each stage. A policy will give
a consistent manner in which to perform each stage. Part of the policy should
include documenting every important piece of information.
Gathering
Symptoms
To perform the "Gathering Symptoms" stage of the
general troubleshooting process, the troubleshooter gathers and documents
symptoms from the network, end systems, or users. In addition, the
troubleshooter determines what network components have been affected and how
the functionality of the network has changed compared to the baseline. Symptoms
may appear in many different forms. These forms include alerts from the network
management system, console messages, and user complaints.
While
gathering symptoms, questions should be used as a method of localizing the
problem to a smaller range of possibilities. However, the problem is not truly
isolated until a single problem, or a set of related problems, is identified.
Isolation of Problem
To perform the "Isolate the
Problem" stage of the general troubleshooting process, the troubleshooter
identifies the characteristics of problems at the logical layers of the network
so that the most likely cause can be selected. At this stage, the
troubleshooter may gather and document more symptoms depending on the problem
characteristics that are identified.
Correct the Problem
To
perform the "Correct the Problem" stage, the troubleshooter corrects
an identified problem by implementing, testing, and documenting a solution. If
the troubleshooter determines that the corrective action has created another
problem, the attempted solution is documented, the changes are removed, and the
troubleshooter returns to gathering symptoms and isolating the problem.