Foundation Topics

A typical Enterprise network consists of several sites. The end-user devices connect to a LAN, which allows the local computers to communicate with each other. Additionally, each site has a router that connects to both the LAN and a wide-area network (WAN), with the WAN providing connectivity between the various sites. With routers and a WAN, the computers at different sites can also communicate.

This chapter describes the basics of how to create LANs today, with Chapter 4, “Fundamentals of WANs,” describing the basics of creating WANs. Ethernet is the undisputed king of LAN standards today. Historically speaking, several competing LAN standards existed, including Token Ring, Fiber Distributed Data Interface (FDDI), and Asynchronous Transfer Mode (ATM). Eventually, Ethernet won out over all the competing LAN standards, so that today when you think of LANs, no one even questions what type—it’s Ethernet.