A transparent bridge can forward and filter frames snd automatically build its forwarding table.
A bridge can use the spanning tree algorithm to create a loopless topology.
A backbone LAN allows several LANs to be connected.
A backbone is usually a bus or a star.
A virtual local area network (VLAN) is configured by software, not by physical wiring.
Membership in a VLAN can be based on port numbers, MAC addresses, IP addresses, IP multicast addresses, or a combination of these features.
VLANs are cost- and time- efficient, can reduce network traffic, and provide an extra measure security.