Computer networks can be classified into three broad categories.
Local area network (LAN)
A local area network remains confined in a relatively small space. It is useful in providing services to a small number of people. Networks in small offices, and homes are some examples of LAN.
Small office and Home networks are also peer-to-peer networks where minimum resource is used and each client shares their resources with other workstations in the network.
Another LAN is a client-server network where every client remains connected to the server and each other. Servers in client-server networks are of different capacities. There are two types of client-server networks:
- Single-service servers performing single task, say, as a file server; and
- Print server performing multiple tasks, say, as file server, print server, conducting calculations and providing information to client on basis of result of the calculations.
Ethernet cables, Wireless networks, or other types of wires such as power lines or phone lines may be used to connect computers in LAN.
Wide area network (WAN)
Wide variety of resources is deployed in WAN. These networks spans not only over large domestic area but also internationally. The connectivity of computers in branch offices of a corporate organization is an example of WAN. But the greatest WAN on the earth is Internet, a network of numerous smaller networks. Besides Internet, another enormous WAN is Public Switched Telephone Network which is converging fast with the Internet technologies.
Wireless networks (WLAN, WWAN)
A wireless network is based on data transmission over sets of radio transceivers. Basically it is same as a LAN or a WAN. Only difference is that there are no wires between hosts (clients) and servers. These types of networks are useful for locations where setting up wired networks is either too costly or inconvenient. It uses IEEE media access protocols for LANs. For connecting nodes over larger distance either satellite communications of various types or cellular radio or wireless local loop are in vogue. But speed and quality of data transmission varies largely depending on the means of communication used.