How Home Networks Work: LAN, WAN, ISP, VLAN, and VPN Explained

A home network connects local devices — such as laptops, phones, and smart TVs — to the internet through a router that bridges two distinct sides: the LAN (Local Area Network) for internal devices and the WAN (Wide Area Network) facing the upstream ISP. LAN and WAN are relative concepts, not fixed physical connection types; the same Ethernet link can serve as either depending on which router's perspective is considered. Internet Service Providers assign the router a WAN-side IP address, which may be a globally routable public address or a private one depending on the ISP's architecture. When devices use private IP addresses, the router performs Network Address Translation (NAT) to map local traffic to its public-facing address before it reaches the internet. Additional technologies such as DHCP, firewalls, VLANs, and VPNs layer on top of this basic topology to manage, segment, and secure network traffic.