1.1.2 Seven-Step Troubleshooting Process
The figure displays a more detailed seven-step troubleshooting process. Notice how some steps interconnect. This is because, some technicians may be able to jump between steps based on their level of experience.
Define the Problem
The goal of this stage is to verify that there is a problem and then properly define what the problem is. Problems are usually identified by a symptom (e.g., the network is slow or has stopped working). Network symptoms may appear in many different forms, including alerts from the network management system, console messages, and user complaints.
While gathering symptoms, it is important to ask questions and investigate the issue in order to localize the problem to a smaller range of possibilities. For example, is the problem restricted to a single device, a group of devices, or an entire subnet or network of devices?
In an organization, problems are typically assigned to network technicians as trouble tickets. These tickets are created using trouble ticketing software that tracks the progress of each ticket. Trouble ticketing software may also include a self-service user portal to submit tickets, access to a searchable trouble tickets knowledge base, remote control capabilities to solve end-user issues, and more.
Gather Information
In this step, targets (i.e., hosts, devices) to be investigated must be identified, access to the target devices must be obtained, and information gathered. During this step, the technician may gather and document more symptoms, depending on the characteristics that are identified.
Analyze Information
Possible causes must be identified. The gathered information is interpreted and analyzed using network documentation, network baselines, searching organizational knowledge bases, searching the internet, and talking with other technicians.
Eliminate Possible Cause
If multiple causes are identified, then the list must be reduced by progressively eliminating possible causes to eventually identify the most probable cause. Troubleshooting experience is extremely valuable to quickly eliminate causes and identify the most probable cause.
Propose Hypothesis
When the most probable cause has been identified, a solution must be formulated. At this stage, troubleshooting experience is very valuable when proposing a plan.
Test Hypothesis
Before testing the solution, it is important to assess the impact and urgency of the problem. For instance, could the solution have an adverse effect on other systems or processes? The severity of the problem should be weighed against the impact of the solution. For example, if a critical server or router must be offline for a significant amount of time, it may be better to wait until the end of the workday to implement the fix. Sometimes, a workaround can be created until the actual problem is resolved.