What is the difference between a VLAN and a VPN?

A VLAN logically separates a layer-2 network into distinct broadcast domains over shared switching infrastructure. A VPN provides a logical connection or overlay across another network, often with encryption and authentication depending on the technology. VLAN membership does not encrypt traffic, and a VPN does not automatically authorize access to every internal resource. Inter-VLAN routing and firewall policy control communication between segments. Describe the specific technology and threat model when discussing protection, because both terms cover designs with different isolation and trust properties.