What is a network?

The so-called computer network refers to a group of computers that can be connected independently.

"Interconnection" here means that two or more computers are connected to each other, and they can exchange information and share resources.

And "independence" means that each computer works independently, and no computer can interfere with the work of other computers. If you start and stop, there is no master-slave relationship between any two computers.

From this simple definition, we can see that computer network involves three aspects.

(1) Two or more computers can be connected with each other to form a network to achieve the purpose of sharing resources.

(2) Two or more computers need a channel to communicate and exchange information with each other. The connection of this channel is physical and realized by hardware, which is the connection medium (sometimes called information transmission medium). They can be "wired" media, such as twisted pair, coaxial cable or optical fiber; It can also be a "wireless" medium, such as laser, microwave or satellite.

(3) Computers need some conventions and rules to communicate and exchange information, which is a kind of agreement.

Therefore, we can define the computer network as:

A system that connects many computers with independent functions distributed in different places through communication equipment and lines, and realizes resource sharing in the network under the operation of fully functional network software.