What Is a VLAN?

When set up correctly, virtual LANs improve the performance of busy networks. VLANs can group client devices that communicate frequently with each other.

The traffic among devices split across two or more physical networks is usually handled by a network’s core routers. With a VLAN, that traffic is handled more efficiently by
network switches.

VLANs also bring security benefits to 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.

Static and Dynamic VLANs
Network administrators often refer to static VLANs as port-based VLANs. In a static VLAN, an administrator assigns individual ports on the network switch to a virtual network. No matter what device plugs into that port, it becomes a member of that specific virtual network.

In dynamic VLAN configuration, an administrator defines network membership according to characteristics of the devices rather than the switch port location.
For example, a dynamic VLAN can be defined with a list of physical addresses
(MAC addresses) or network account names.

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