Network Definitions

Computer networks can be classified and defined according to geographical area that the network covers. There are four network definitions: a Local Area Network (LAN), a Campus Area Network (CAN), a Metropolitan Area Network (MAN), and a Wide Area Network (WAN). There are three additional network definitions, namely the Internet, an intranet and an Internetwork. These network definitions are discussed in Table 1.2.

Definition	Description
Local Area Network (LAN)	A LAN is defined as a network that is contained within a closed environment and does not exceed a distance of 1.25 mile (2 km). Computers and peripherals on a LAN are typically joined by a network cable or by a wireless network connection. A LAN that consists of wireless connections is referred to as a Wireless LAN (WLAN).
Campus Area Network (CAN)	A CAN is limited to a single geographical area but may exceed the size of a LAN
Metropolitan Area Network (MAN)	A MAN is defined as a network that covers the geographical area of a city that is less than 100 miles.
Wide Area Network (WAN)	A WAN is defined as a network that exceeds 1.25 miles. A WAN often consists of a number of LANs that have been joined together. A CAN and a MAN is also a WAN. WANs typically connected numerous LANs through the internet via telephone lines, T1 lines, Integrated Services Digital Network (ISDN) lines, radio waves, cable or satellite links.
Internet	The Internet is a world wide web of networks that are based on the TCP/IP protocol and is not own by a single company or organization.
Intranet	An intranet uses that same technology as the Internet but is owned and managed by a company or organization. A LAN or a WAN s usually an intranet.
Inter network	An inter network consists of a number of networks that are joined by routers. The Internet is the largest example of an inter network.

TABLE 1.2: Network Definitions

Of these network definitions, the most common are the Internet, the LAN and the WAN.