This section further discusses topics such as STP and VTP and how they affect your VLANs. For example, it wasn't too inspiring to lose your VLANs earlier, but it's better to have this happen in a lab than in a practical environment. Understanding VTP is critical to your success in supporting VLANs. Using the default of every switch being in the VTP server mode is chaotic to say the least. At most, only a few switches should be in the VTP server mode with many clients. Alternatively, configure them all as transparent mode. You previously learned how to control which VLANs are allowed on a trunk. Now you will optimize and control VLANs with pruning.