Virtual LAN Technology
These are special purpose devices and computers that just transfer messages from one network to another. Before we look deep into the topic Virtual LAN's, let us see the basic devices used in the network backbone. They are
BRIDGES :Bridges operate at the data link layer. They connect two LAN segments that use the same data link and network protocol.
SWITCHES :Like bridges, switches operate at the data link layer. Switches connect two or more computers or network segments that use the same data link and network protocol.
ROUTERS :Routers operate at the network layer. Routers connect two or more LANs that use the same or different data link protocols, but the same both the basic system interconnection and the necessary translation between the protocols in both directions.
HUBS : Physical layer devices that are really just multiple port repeaters. When an electronic digital signal is received on a port, the signal is reampli-fied or regenerated and forwarded out all segments except the segment from which the signal was received.