What term describes a logical grouping of network devices into a single broadcast domain?

• A. Subnet
• B. VPN
• C. VLAN
• D. NAT

Answer: (C)

Grouping devices into a single broadcast domain is achieved with a VLAN. A broadcast domain is the set of devices that receive a broadcast frame sent on the local network. A VLAN partitions the network at Layer 2 so that all devices assigned to the same VLAN behave as if they’re on the same local segment, regardless of their physical location. Switches keep track of which ports belong to which VLAN, and broadcast frames are flooded only to ports in that VLAN. If devices in different VLANs need to talk, a router or layer 3 switch is required to route between them, which inherently separates their broadcast domains.

The other terms don’t describe this concept. A subnet relates to IP addressing and routing boundaries at Layer 3, not to a Layer 2 broadcast domain. NAT translates private IP addresses to public ones, and a VPN creates a secure connection over a public network; neither defines or confines a broadcast domain.