Technology that allows network administrators to create logical groupings of devices within a network, regardless of their physical location.
VLANs work at The Link Layer of The OSI Model and use tags in the Ethernet Frame headers to identify which VLAN the traffic belongs to.
The IEEE 802.1Q standard defines how these VLAN tags are implemented.
Network Switches that support VLANs can read these tags and ensure traffic only flows between ports assigned to the same VLAN.
To communicate between different VLANs, traffic must pass through a Router or Layer 3 switch that supports inter-VLAN routing.