bridging and routing. Like a bridge, a VLAN switch forwards traffic based on the Layer 2 header,
which is fast. Like a router, it partitions the network into logical segments, which provides better
administration, security, and management of multicast traffic.

A VLAN is a set of end stations and the switch ports that connect them. You can have different

reasons for the logical division, such as department or project membership. The only physical
requirement is that the end station and the port to which it is connected both belong to the same
VLAN.

Each VLAN in a network has an associated VLAN ID, which appears in the IEEE 802.1Q tag in
the Layer 2 header of packets transmitted on a VLAN. An end station might omit the tag, or the
VLAN portion of the tag, in which case the first switch port to receive the packet can either reject
it or insert a tag using its default VLAN ID. A given port can handle traffic for more than one
VLAN, but it can support only one default VLAN ID.