The reasons for keeping the computers on the network are:

1. To share hardware resources.
2. To share the application software, data, files, and so on.
3. To make communication and transmission reliable.
4. To reduce the expenses of computer accessories.

A computer network is the interconnection of computers to share the data, files, hardware, software, and so on. It also makes the communication and transmission reliable In the offices, the files should be transferred from one to other branches very often. Also, the software and hardware can be shared which reduces the cost of buying many items of hardware, software, and so on. So, computer network reduces expenses of offices.

The interconnection of two or more computers by means of transmission media like cable or without cables in order to communicate and share resources data, application software, and hardware is known as a computer network. Its advantages are:

1. Hardware sharing.
2. Data and software sharing.
3. Transfering and communication facilities.
4. Security and reliability.
5. Sharing the resources remove its cost or reduce the cost.
   

The transmission of data from a place to another using computer technology is called data communication.

The act of transferring data and information at a far distance for communication is called telecommunication.