16Chapter 2 Initial Troubleshooting
Logical connections
You must know how your devices are connected logically as well as physically. For example, while virtual LANs (VLANs) are not supported on the BCM450 system, VLANs may exist between IP sets connected to the BCM450.
Device configuration information
You should maintain online and paper copies of your device configuration information. Ensure that all online data is stored with your site’s regular data backup. If your site does not have a backup system, copy the information onto a backup disk (such as a CD or zip disk) and store the backup disk at an offsite location.
Other important data about your network
For a complete picture of your network, have the following information available:
•All
•Device
•MAC
•Change
•Contact
Normal behavior on your network
When you are familiar with the performance of your network when it is fully operational, you can be more effective at troubleshooting problems that arise. To understand the normal behavior of your network, monitor your network over a long period of time. During this time you can see a pattern in the traffic flow, such as which devices are typically accessed or when peak usage times occur.
To identify problems, you can use a baseline analysis, which is an important indicator of overall network health. A baseline serves as a useful reference of network traffic during normal operation, which you can then compare to captured network traffic while you troubleshoot network problems. A baseline analysis speeds the process of isolating network problems. By running tests on a healthy network, you compile normal data for your network. This normal data can then be