virtual lan

1 definition found

virtual lan - Free On-line Dictionary of Computing (26 May 2007) :

  Virtual LAN
  
     <networking> Software defined groups of host on a local area network
      (LAN) that communicate as if they were on the
     same wire, even though they are physically on different LAN segments
      throughout a site.  To define a virtual LAN, the
     network administrator uses a virtual LAN management utility
     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
     switched at the data link layer (OSI layer 2).  Virtual
     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
     Network Layer (OSI layer 3).  Subnet-oriented virtual LANs
     are based on subnet addresses used by IP, IPX, and other
     network layer protocols to normally identify physical
     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,
     the selected LANs function as a bridge group - traffic is
     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)