Chapter Summary
WANs connect LANs in geographically separate areas. WAN connections are typically part of the Physical and Data Link layers of the OSI model and are made over serial connections.
WAN connections are typically lower speed than LAN connections.
WAN connections can be made as point-to-point, point-to-multipoint, and switched WAN connections.
Several different data link protocols can be used for WAN connections. The different types of WAN connections are SDLC, HDLC, PPP, and switched or relayed services including X.25, Frame Relay, ATM, and ISDN.