A computer network can be classified into different categories. Different criteria are used to classify computer networks. Following are the criteria widely used.
• Geographical spread
Classification by Geographical Spread
Based on geographical spread, networks can be classified into the following three categories.
• Local Area Network (LAN)
• Metropolitan Area Network (MAN)
• Wide Area Network (WAN)
Local area network (LAN) LAN is a computer network that consists of few or more computers and other communication devices connected in the form of a network within a well-defined area such as a room or a building.
A typical example is a college or university computer network. Users in a LAN can share both hardware and sharable software resources. For example, hardware resources include expensive laser printer, plotter, fax machines, modem, etc. Almost all local area networks use a single communication media, as it restricted to a limited area. All network resources and their management activities are controlled using special system software called Network Operating System (NOS).
Metropolitan area network (MAN) MAN is a network more extensive than a LAN. The name metropolitan is due to the ability to cover a relatively larger area of a city, from a few tens to a maximum of hundred kilometers. Different hardware and transmission media often used in a MAN for efficient transmission of information.
Wide area network (WAN) WAN is a computer network that spans a large geographical area. It uses dedicated or switched connections to link computers in geographically remote locations. Wide area networks are implemented to connect a large number of LANs and MANs. Due to this reason, it is possible to see a large number of heterogeneous components in a wide area network. Different communication media used, and the network spreads across several national boundaries. Computers connected to a WAN often connected to a public network. They can also be connected through leased lines or satellite links. The government or large concerns mostly use WAN because of the considerable investment made to implement them.
There are three categories of wide area networks, namely
Enterprise network: An interconnected version of all the local area networks of a single organization is known as an enterprise network.
Global network: A network formed by combining the networks of several organizations over a wide area.
Internet: A network of networks of broad area category. It is the biggest network in the world. The network components are LANs, WANs, MANs, and millions of autonomous computers of different category. A single authority does not control the network; the local, national authority controls every segment of the Internet.