VLAN Tagging Explained
VLAN Tagging is the practice of inserting a VLAN ID into a packet header in order to identify which VLAN (Virtual Local Area Network) the packet belongs to. More specifically, switches use the VLAN ID to determine which port(s), or interface(s), to send a broadcast packet to.
For more information, you can download a PDF here.
If you have a VLAN enabled switch, you can make your CT boxes part of your existing network. Enabling this will disable other features in CT.