Ans : Wide Area Network (WAN)
Wide Area Network provides no limit of distance. In most WANs, the subnet consists of
two distinct components. Transmission lines are also called circuits or channels or links
and switching and routing devices (switches & routers). Transmission-lines are used for
moving bits between machines, whereas routers are used to connect two or more
transmission lines.
A WAN provides long distance transmission of data, voice, image and video
information over large geographical areas that may comprise a country, a continent or
even the whole world.
In contrast to LANs (which depend on their own hardware for transmission), WANs
may utilize public, leased or private communication devices usually in combination and
span own unlimited number of miles.
A WAN that is wholly owned by a single company is often referred to as an enterprise
network.
A Local Area Network (LAN) is generally a privately owned network within a single
office, building or campus, covering a distance of a few kilometers. The main reason for
designing a LAN is to share resources such as disks, printers, programs and data. It also
enables the exchange of information. Classically, LANs had data rates of 4-16 Megabits
per second (Mbps). Later, 100 Mbps LANs were introduced. Today, LANs with data
rates of thousands of Mbps are possible. LANs typically can use the star, bus or a ring
topology. However, bus topology is popular in the Ethernet LANs and Token Bus LANs
and ring topology is popular in the Token Ring LANs of IBM. A modified version of
Token Ring is Fiber Distributed Data Interface (FDDI). Of these, Ethernet and Token
Ring are the most popular LANs.
