What is Virtual Local Area Network (VLAN)?
VLAN is a networking technology that allows networks to be segmented logically without having to be physically rewired.
Many Ethernet switches support virtual LAN (VLAN) technologies. By replacing all hubs with VLAN switches, the network administrator can create virtual network within existing network. With VLAN, its logical topology is independent of the physical topology of the wiring. Each computer can be assigned a VLAN identification number (ID), and computers with the same VLAN ID can act and function as though they are all on the same physical network. So, the traffic on VLAN is isolated and thus all communications remain within the VLAN. The assignment of VLAN IDs is done by the switches and can be managed remotely using network management software.
VLAN switches can function in different ways. They can be switched at the data-link layer (layer 2 of the Open Systems Interconnection reference model) or the network layer (layer 3), depending on the type of switching technology used. The main advantage of using VLAN technologies is that users can be grouped together according to their need for network communication, regardless of their actual physical locations. This isolation will help to reduce unnecessary traffic so better network performance. The disadvantage is that additional configuration is required to set up and establish the VLANs when implementing these switches.