Introduction to WAN Technologies

A Wide Area Network (WAN) is best described as a data network that covers a relatively broad geographic distance. Unlike a LAN, which is usually localized within a relatively small area such as a single office, building, or small campus, a WAN will typically span distances of anywhere from a few, to thousands of kilometers. Besides distance, LANs and WANs are generally differentiated by network ownership. With a LAN, companies typically own and operate all of the equipment that interconnects devices – switches, routers, wiring, and so forth. This is usually not the case with a WAN, where a service provider (such as a local telecommunications carrier) generally owns the network links and switching equipment.

In order to interconnect geographically dispersed locations, companies will usually provision services from a telecommunications carrier, generally renting or leasing links on a monthly basis. The speed and cost of these links can vary greatly, depending upon bandwidth requirements, distances to be spanned, and available technologies. As a general rule, WANs are implemented at speeds much slower than their LAN counterparts, with higher bandwidth requirements significantly increasing monthly costs. This is a function of simple economics – providers have made huge investments in building their networks and are doing their best to make money. For companies, choosing the most appropriate WAN technology involves finding a cost-effective solution that meets their performance, reliability, and scalability requirements.

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.