Early LANs were vendor specific. Standardization efforts by the IEEE have resulted in the IEEE 802 series of standards. There are now two common wiring technologies for a LAN, Ethernet and Token Ring. Wireless technologies are starting to evolve and are convenient for Mobile computer users.
When using Ethernet the computers are usually wired to a hub. This constitutes the physical transport mechanism.
A number of network protocols may use the basic physical transport mechanism including TCP/IP. In this case DHCP is a convenient way to obtain an IPaddress? rather than using fixed addressing. LANs can be interlinked by connections to form a Wide area network (WAN?). A Router is used to make the connection between LANs.