1.5 LAN, WANs and Internetworks

One can differentiate between networks according to (1) the number of users connected; (2) the size of the area covered; and (3) the number and types of services available. According to the size of the area covered, networks can be classified into:

1-	A local area network (LAN) is a group of network devices connected in a small region, such as building, buildings
	close together, or an area less than 2 mills. It is usually privately owned.

1.5 LAN, WANs and Internetworks

2-	A wide area network (WAN) provides long-distance transmission of data/information over large
	geographic areas that may comprise a country, a continent, or even the whole world.

3-	A metropolitan area network (MAN) is a network with a size between a LAN and a WAN. It normally
	covers the area inside a town or a city. It is designed for customers who need a high-speed
	connectivity, normally to the Internet, and have endpoints spread over a city or part of city.

1.5 LAN, WANs and Internetworks

An internetwork is a collection of two or more LANs connected by WANs. The most important internetwork is the Internet, which is open to public use. A special types of internetwork are intranet, and extranet.

A company that provides access to the Internet is called Internet service provider (ISP). All Internet users access the web through ISPs. The ISPs cooperate with other ISPs to make sure that all users have access to the web. This involves implementing rules and standards that enable any user to communicate with any other user independent of location and device type.

1.5 LAN, WANs and Internetworks

The World Wide Web ( WWW or commonly known as the Web) is a system of Internet servers that support specially formatted documents, called HyperText Markup Language HTML, HTML supports links to other documents, as well as graphics, audio, and video files.