networking Software defined groups of
host on a
localarea network (LAN) that communicate as if they were on the
same wire, even though they are physically on different
LANsegments throughout a site. To define a virtual LAN, the
to establish membersip rules that determine which hostss are
in a specific virtual LAN. Many models may exist but two seem
to dominate:
(1) Vitual Segment (or Port-Group) Virtual LAN. These are
segments turn an arbitrary number of physical segments into a
single virtual segment that funtions as a self-contained
traffic domain.
(2) Virtual Subnet Virtual LAN: These are switched at the
networks. Administrators assign one subnet address to a
number of switch
ports (which may be on different switches
and over a backbone). Once identified as a virtual subnet,
bridged at Layer 2 within the virtual subnet and routed at
Layer 3 between virtual subnets.
["The many faces of virtual LANs", Steven King, Network
World, 1994/5?].
(1995-04-03)