In-depth analysis of various types of data exchange technology

There are many things worth learning about data exchange technology. Here we mainly introduce various types of data exchange technology. Today, the concept of network is deeply rooted in the hearts of the people. In our daily life, everyone is accessing the network, such as cable TV networks, the Internet, communication networks (telephones), power networks, and computer networks. So what is a real network?

In my opinion, ordinary cable TV networks and power networks that do not have data exchange are not called networks. They can only be viewed as physical networks. Only networks capable of data exchange can be called networks. Therefore, data exchange technology is the core technology of networks. Generally, three data exchange technologies are used: line exchange, Packet Exchange, and group exchange.

I. Line Switching

Line switching is to establish a dedicated communication line between two sites through nodes in the network. 1 telephone system, this line switching system, has an actual physical connection between two stations, which is the connection sequence between nodes. A point-to-point line must be established between transmission of any data. If site 1 sends a request to node 2 and the request establishes a connection with site 2, site 1 to node 1 is a dedicated line. Assign a dedicated channel on the vswitch to connect to node 2 and then to Site 2. So far, a physical communication channel has been established from site 1 through Node 2 to Site 2. In this way, the voice can be transmitted from site 1 to Site 2. Generally, this connection is full-duplex, and the voice (data) can be transmitted in two directions ). After the data transmission is complete, the channel to be established must be removed. Generally, one of the two sites is used to release dedicated resources.

Ii. Packet Exchange

This exchange method does not need to establish a dedicated channel between two sites. If a station wants to send a message (a logical unit of information) to Site 2 ), it attaches the address (The Address Code) of Site 2 to the packet to be sent. Then, the packet is sent from the node to the node through the network. In each node (if multiple nodes are required to be sent to the Site 2), the entire packet is received and the packet is saved, then, it is sent to the next node. In data exchange technology, each node is an electronic or electromechanical exchange device, and each node is usually a general small computer. It has enough storage capacity to cache incoming packets. The delay time of a message on each node is equal to the time required for receiving all the packets, plus the waiting time and the queuing delay time required for re-transmission to the next node. Packet Exchange has the following advantages:

1. High Line efficiency, because many packets can share a channel from a node to a node in time-sharing mode.

2. You do not need to use a sender or receiver to transmit data at the same time. The network can temporarily store this message before the receiver is available.

3. Some calls cannot be accepted when the communication volume becomes large on the line switching network. However, in Packet Exchange, messages can still be received, but the transmission delay will increase.

4. The message exchange system can send one message to multiple destinations.

5. Establish the priority of the message.

6. The packet exchange network can convert the speed and code. Because each station can use its unique data transmission rate to connect to other sites, two sites with different transmission rates can also be connected, you can also convert the format of the transmitted data.

Iii. group exchange

The Group switching method has the advantages of packet switching and line switching. The form is very similar to message exchange. The main difference is that the length of the data unit needs to be limited in the packet exchange network. Generally, the number of bytes that can be transmitted in the packet exchange system can be very long. In the data exchange technology, the maximum length of a message is limited. If the length is exceeded, the message must be divided into smaller units and sent in sequence, we usually call these smaller data units as groups. This is the difference between the Packet Exchange and the group exchange.