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| 2.2 |  | Troubleshooting Approaches |
| 2.2.1 |  | General troubleshooting process |

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.