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?].

< Previous Terms Terms Containing Virtual LAN Next Terms >
Virtual Device Driver
Virtual Device Location
virtual disk
Virtual Home Environment
virtual host
Network Address Translation
Virtual LAN
Virtual Loadable Module
Virtual Local Area Network
Virtual Machine
virtual machine
Virtual Machine/Conversational Monitor System