A virtual LAN (Local Area Network) is a logical subnetwork that can group together a collection of devices from different physical LANs. Larger business computer networks often set up VLANs to re-partition their network for improved traffic management.
When set up correctly, virtual LANs can improve the overall performance of busy networks. VLANs are intended to group together client devices that communicate with each other most frequently. The traffic between devices split across two or more physical networks ordinarily needs to be handled by a network's core routers, but with a VLAN that traffic can be handled more efficiently by network switches instead.
VLANs also bring additional security benefits on larger networks by allowing greater control over which devices have local access to each other. Wi-Fi guest networks are often implemented using wireless access points that support VLANs.
Network administrators often refer to static VLANs as “port-based VLANs.” A static VLAN requires an administrator to assign individual ports on the network switch to a virtual network. No matter what device plugs into that port, it becomes a member of that same pre-assigned virtual network.
Dynamic VLAN configuration allows an administrator to define network membership according to characteristics of the devices themselves rather than their switch port location. For example, a dynamic VLAN can be defined with a list of physical addresses (MAC addresses) or network account names.
