WAN
Wide Area Network
A network that spans large geographic distances — connecting local networks (LANs) to the internet or to each other across cities, countries, and continents. The internet itself is the world's largest WAN. On your home router, the WAN port is where the ISP connection plugs in.
Every home and office network has two sides: the LAN (your devices, under your control) and the WAN (the connection to your ISP and beyond). The router sits between them, performing NAT to translate between your private LAN IP addresses and the single public IP address your ISP assigns. WAN connections are characterised by higher latency (distance), lower bandwidth than local LAN links, and external ownership — you don't control the WAN infrastructure, your ISP does. Enterprise WANs connect branch offices using leased lines, MPLS circuits, or VPNs over the internet.
WAN vs LAN
| Property | LAN | WAN |
|---|---|---|
| Geographic scope | Single location (home, office, campus) | Cities, countries, global |
| Ownership | You own and manage it | ISP / carrier / public internet |
| Typical speeds | 1–10 Gbps (Ethernet) | 10 Mbps–10 Gbps (consumer/enterprise) |
| Latency | <1ms (local switch) | 5–300ms (distance-dependent) |
| IP addresses | Private (RFC 1918) | Public (ISP-assigned) |
| Cost per byte | None (flat hardware cost) | Metered at high volumes |
WAN connection types
Consumer WAN connections include cable (DOCSIS, shared coaxial), fibre (GPON, XGS-PON, dedicated fibre), DSL (ADSL/VDSL over copper phone lines), fixed wireless (LTE/5G to a home antenna), and satellite (Starlink, geostationary). Enterprise WAN uses MPLS (private managed circuits with QoS guarantees), leased lines (dedicated symmetric bandwidth), SD-WAN (software-managed multi-link WAN), or IPsec VPN tunnels over the internet to connect branch offices. Each technology has different latency, symmetry, reliability, and cost characteristics.
Frequently Asked Questions
What is the difference between WAN and LAN?
LAN is your local network — devices you own, private IPs, fast and free. WAN is the connection to the outside world via your ISP — public IP, subject to distance latency, and operated by a carrier. Your router has a LAN side (your devices) and a WAN side (ISP connection), performing NAT between them.
What is the WAN port on a router?
The port connecting your router to the ISP — modem, ONT, or cable gateway. Traffic in = from internet; traffic out = to internet. Your ISP assigns a public WAN IP via DHCP, PPPoE, or static. Some routers have dual WAN ports for load balancing or failover between two ISP connections.
What is SD-WAN?
Software-Defined WAN — uses software to route enterprise traffic intelligently across multiple WAN links (MPLS, broadband, 4G/5G) based on application needs and real-time link quality. Replaces expensive MPLS-only WANs with cheaper broadband while maintaining performance for latency-sensitive traffic like VoIP.