1.1计算机网络的定义(国外英语资料)
1.1计算机网络的定义
1.1 definitions of computer networks
Before giving the definition of a computer network, let’s first review the concept of what is already known as the “network”. “Network” usually refers to a set of objects or objects that are linked or combined in some way in order to achieve a certain goal. Such as our daily life in all directions transportation system, water supply or power supply system, postal system and so on, is some kind of network. So what is a computer network?
Computer network refers to multiple computer systems in different locations and the independent functions through the communication lines are connected together by a network operating system, special management system, to achieve resource sharing.
“Geographically different” means that computers in a computer network are usually in different geographical locations. For example, when the students access to network services through the Internet, access the host is often not visible in the geographical, not only that, the host may also be located in different provinces, city and even different countries with the students. In fact, in most cases, people don’t even know the exact location of it. It is the spatial barrier formed by geographical distribution that becomes the original driving factor for the sharing of resources in the form of computer networks.
“Function is relatively independent” means that there is no mutual dependence between computers. As separate computer systems, they have separate software and hardware, and any computer can work independently of the network and other computers in the network. For example, students at home in the Internet for the computer can be connected to the Internet, can also be separated from the network, stand-alone operation.
When these geographically different computers form a computer network, they must be interconnected by means of communication lines. The communication line consists of communication medium and communication control device. Howe