What is the purpose of a VLAN?

• A. To encrypt traffic across the network.
• B. To segment a network into separate broadcast domains for logical separation.
• C. To connect two networks over the internet.
• D. To extend a single broadcast domain across the entire network.

Answer: (B)

VLANs create separate broadcast domains for logical separation. By assigning switch ports to the same VLAN, devices share a common Layer 2 network, and broadcast frames stay within that VLAN rather than roaming to all devices on the network. This reduces unnecessary traffic, improves security by isolating groups (like departments or user types), and makes network management more scalable since you can segment the network without adding physical switches everywhere.

If devices in different VLANs need to talk, inter-VLAN routing is required, typically with a router or Layer 3 switch. VLAN tagging (like 802.1Q) lets multiple VLANs traverse a single trunk link between switches, enabling centralized management while keeping traffic logically separated.

Do note that encryption and VPNs serve different purposes: encryption protects data in transit, while VPNs connect networks over the internet. A VLAN does not extend a single broadcast domain across the entire network; it deliberately creates multiple broadcast domains to limit broadcast traffic.