Introduction of Computer Network.

When two or more computers linked together for the purpose of sharing (sending/receiving) data and information, known as Computer Network.

Computer Network

Network Goals and Applications

Resource Sharing: The hardware devices like printers and scanners can be shared over a Network. This reduces costs by reducing the number of hardware items.
Storage Sharing: On a network, the user can access the data of another machine and can store data on another machine.
Reliability: A file can have copies on two or three different computers. So, if one is not available other copies can be used.
Access to a remote database: User can access the Host computer at his PC and send the request. For example - users can make flight reservations, book hotels, and so on anywhere in the world with instant confirmation.
Communication Facilities: Network provides us facilities to communicate with others via Emails, Chats, Video conferencing, and so on.

Complex: Systems are more complex to run.
Server fails: If all data are held centrally in a server. It may create problems if the central server fails.
Expensive to install: Cables, Network devices, NIC, and Softwares required for installation of the network. And these are quite expensive.