Viewpoint: In-depth study of the six features of group exchange network

As we all know, in a group network, a group exchange network can freely choose a transmission channel to ensure the overall performance of our network. A group exchange network is also called a Packet Exchange Network. The group switch divides the data to be transmitted into several data segments in a certain length. These data segments are called "groups" or "packets ). During transmission, the control information and address identification must be added before each group, that is, the group header), and then transmitted in the network in the form of "Storage and forwarding.

When the destination is reached, the switch removes the grouping header, installs the split data segments in order, and restores them to the sending end file to the receiving end user. This process is called the Group switching network. A communication network for group exchange is called a group exchange network. This process is similar to our usual mailing, as shown in 1.

People wrap up a good credit envelope and write the recipient's address and name on the envelope, which is equivalent to routing control information in the group header. After the envelope is prepared, it is put into the mailbox, the post office sorts the packets, sends them to different locations, and finally sends them to the recipient. The recipient opens a letter to read the packets, just like unpacking in the group. This entire process is like a group exchange process. However, in order to accurately, reliably, and quickly transmit information to each other, group exchange is much more technically complicated.

High Information Transmission Quality

The group exchange network method has a strong error control function. It not only adopts the error verification and resend functions when transmitting packets between node switches, but also has some terminals with the function of grouping and removing, the user line can also carry out error control, thus greatly reducing the error rate of group transmission in the network. When the error rate of the transmission circuit is 1x10-5, the error rate of the entire packet switching network is less than 1x10. Therefore, the packet switching can greatly improve the transmission quality.

High Network Reliability

In a group-based exchange network, a dynamic routing algorithm is used for routing when a group is transferred over the network. That is, each group-based exchange network can freely select a transmission path, and the switch calculates an optimal path. Because the group switch is connected to at least two other switches, when a switch or trunk line in the network fails, the group can automatically avoid the fault location and select another roundabout route for transmission, communication will not be interrupted.

Convenient communication between different types of terminals

The group exchange network can store and forward the transmitted data so that terminals at different rates can communicate with each other. As the Sub-network provides standard interfaces to users through the X.25 protocol, all devices that do not comply with this Protocol enter the network and the network provides the protocol conversion function, enable terminals with different code types and protocols to communicate with each other.

Low information transmission latency

Because packet storage and forwarding in the network is much lower than the Packet Exchange delay in packet storage and forwarding, it can meet the real-time requirements of session communication.

High Line Utilization

In group switching, the "virtual circuit" technology enables multiple information channels to be provided simultaneously on a physical line, that is, the statistical time division multiplexing of the line is realized, this is not what other networks can do.

Good economic performance

The transfer fee of the group exchange network is independent of the distance. Whether the user is in the same city or across provinces, the fee is calculated based on the same unit price. The fee is only related to the time used and the amount of information transmitted. Therefore, the Group network provides users with economic and affordable means of information transmission.