What is a VLAN?

• A. A logical local area network that extends beyond a single physical LAN.
• B. A physical LAN bound to one building.
• C. A private WAN connection.
• D. A wireless access method for VLAN.

Answer: (D)

A VLAN is a logical segmentation of a local area network that can span multiple physical switches and even different locations. It uses tagging on trunk links (IEEE 802.1Q) so multiple VLANs can travel over a single physical connection. Devices in the same VLAN behave as if they’re on the same LAN, regardless of their actual physical location, while devices in different VLANs require a router or layer-3 device to communicate. It’s not a wireless access method, though wireless networks can carry VLANs by mapping wireless traffic to a VLAN. It also isn’t confined to one building or a private WAN—the whole point is to separate broadcast domains across the network, even across buildings, for better security and traffic management.