One of the core functions of IT is getting data from one place to another. From client to server, from coworker to coworker, from New York to Los Angeles, from workstation to printer. Wherever your data has to go, it needs a network to get there.

Data networks refer to the collection of technologies that get data from one computer to another. The technologies include clients, servers, routers, switches, topologies, protocols, hubs, and cable (copper or fiber). Within these categories you'll find the usual issues of cost, performance, and industry standards. To make things more complicated, you can combine all the variables in many different ways.

Since you can't walk into a retail store or call up your value-added reseller and order a LAN, it is up to you to make decisions about the various technologies and components, which ones you want to use, and how you want to put them together.