Switches may support different numbers of VLANs.
A VLAN, or Virtual LAN, is a local area network with a definition that maps workstations on a basis other than geographic location. For example, it might map by department, type of user, or primary application. The virtual LAN controller can change or add workstations and manage load-balancing and bandwidth allocation more easily than with a physical picture of the LAN.
VLAN is a function of a switch that splits the network into separate parts. It is used for security and (in bigger networks) to simplify relocating of computers and department. For example, with a VLAN, a change could be made only to the switch instead of to 20 separate computers.