A method used to identify packets belonging to different virtual LANs (VLANs) on a network. VLAN tagging is used in network environments where multiple VLANs are employed to segment the network into smaller, more manageable segments. Each VLAN is assigned a unique identifier, or tag, which is used to identify the VLAN to which the packet belongs.
VLAN tagging is a useful tool for network administrators because it allows them to manage the network more easily and to better control the flow of traffic on the network. It is also useful for security purposes, as it allows administrators to create VLANs for specific groups of users or devices, which can help to prevent unauthorized access to certain areas of the network.
VLAN tagging is typically used on switches to allow multiple VLANs to be transmitted over a single physical link. When a packet is received by a switch, the switch looks at the VLAN tag attached to the packet to determine which VLAN the packet belongs to. The switch then forwards the packet to the appropriate port or interface based on the VLAN tag. This allows multiple VLANs to share a single physical link, while still maintaining the separation between VLANs.