Computer Network

COMPUTER NETWORK
A computer network, often simply referred to as a network, is a collection of computers and devices interconnected by communications channels that facilitate communications and allows sharing of resources and information among interconnected devices. Computer networking or Data communications (Datacom) is the engineering discipline concerned with the computer networks. Computer networking is sometimes considered a sub-discipline of electrical engineering , telecommunications, computer science, information technology and computer engineering since it relies heavily upon the theoretical and practical application of these scientific and engineering disciplines.
The three types of networks are: the internet, the intranet, and the extranet. Examples of different network methods are:
  * Local area network (LAN), which is usually a small network constrained to a small geographic area. An example of a LAN would be a computer network within a building.
  * Metropolitan area network (MAN), which is used for medium size area. examples for a city or a state.
  * Wide area network (WAN) that is usually a larger network that covers a large geographic area.
  * Wireless WANs and LANs (WLAN & WWAN) are the wireless equivalent of the LAN and WAN.
Networks may be classified according to a wide variety of characteristics such as topology, connection method and scale.
Computer networks can be used for a variety of purposes:
Facilitating communications 
Using a network, people can communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing.
Sharing hardware 
In a networked environment, each computer on a network may access and use hardware resources on the network, such as printing a document on a shared network printer.
Sharing files, data, and information 
In a network environment, authorized user may access data and information stored on other computers on the network....