Computer networks are classified according to switching modes.

In the computer network, the ways of data exchange are: line switching, message switching and packet switching.

1, line switching. Before data transmission, a physical path needs to be established, which will be completely occupied by a pair of users until the line is released.

2. Information exchange. Messages are transmitted from the sender to the receiver in the form of storage and forwarding. When transmitting messages, only one path is occupied; Buffer storage is needed in the switching node, and messages need to be queued. Therefore, this method does not meet the requirements of real-time communication.

3. Packet switching. This method is similar to message exchange, but the packets are transmitted in groups and the maximum length of the packets is specified. After arriving at the destination, the packet needs to be reassembled into a message. This is the most widely used switching technology in the network.

Early exchange mode:

Circuit switching first appeared in the telephone system, and early computer networks used this method to transmit data. Digital signals can only be transmitted on the line after being converted into analog signals. Information exchange is a digital network.

When communication starts, a message sent by the source machine is stored in the switch, and the switch selects the appropriate path to send the message according to the destination address of the message. This mode is called store-and-forward mode.

Packet switching also uses message transmission, but instead of taking an indefinite message as the basic unit of transmission, a long message is divided into many fixed-length packets, and the packets are the basic unit of transmission.

This not only greatly simplifies the management of computer memory, but also accelerates the spread of information in the network. Because packet switching has many advantages over circuit switching and message switching, it has become the mainstream of computer networks.