WANs connect networks, users, and services across a broad geographic area. Figure 10-1 shows that companies use the WAN to connect company sites and mobile users for information exchange.
Figure 10-1 WAN Connections
LANs connect computers, peripherals, and other devices in a building or small geographic area. WANs connect LANs across a wide geographic area. LANs and all devices in the LAN are usually owned by the local organization. Outside service providers own the WAN and WAN devices.
WANs and their protocols function at Layers ...