Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

164 CHAPTER 10 Network Troubleshooting
Sending Computer
Application
Receiving Computer
Application
Presentation
Presentation
Session
Session
Transport
Transport
Network
Network
Data Link
Data Link
Physical
Physical
Network Media
FIGURE 10.1
Each layer of the OSI model communicates with the corresponding layer
DID YOU KNOW
In general, you can break down the items necessary to troubleshoot a network issue into
the following seven steps:
1. Identify the symptoms and potential causes Determine exactly what’s wrong,
and ensure that there is actually a problem. Ask questions and get very specific
details on the issue. Having as much information as possible at hand will help
you determine the potential causes of an issue.
2. Identify the affected area Is only one user having trouble, or is there an issue
that’s affecting an entire subnet or your entire network
3. Establish what has changed Attempt to discover if anything has changed that may
have caused the issue to surface. Knowing what has changed on a network will
usually give you a good starting point from which you can begin the troubleshooting
process.
4. Select the most probable cause Based on the information you gathered in the
first three steps, try to determine the most likely reason why you are experiencing
the particular problem. Keep in mind that your first guess might be incorrect and
that there may be more than one cause for the problem.
5. Implement an action plan and solution, including potential impact Define the
impact of any steps that you are going to take to fix the problem. Follow any
change management guidance that your organization may have in place and be
thoughtful of any changes you make to production systems.