You can only see the messages you send and receive, and you don’t care about how they are processed layer by layer, nor do you need to care because you are the most advanced user and only need to care about the application, which is the application layer.
How does the OSI model work hierarchically?
Give an example of a visual point.
Li Yunlong had something to ask Chu Yunfei, so he asked Political Commissar Zhao to help write a letter. Li Yunlong called the monk, who put the letter into a briefcase and rode on his horse to the defense zone of the Chu commander of the National Army. Captain Chu opened the letter and immediately replied after reading its contents, handing it over to the monk. The monk mounted his horse and returned to the camp, handing the reply over to Li Yunlong. After reading the letter, Brother Yunlong was overjoyed.

In the above example, we can sort out this relationship and you will know whether this model comes from human conventional cognition.

So the process of Chu Yunfei’s reply is the same as the above process, but there is a small difference. Captain Chu is a cultural person, and he should be the only one responsible for the application and presentation layers.
So in network communication, these seven layers must also be clearly defined, slightly more complex than sending a message from Li Yunlong, but not much more complex, as shown in the table below:

You see, as long as you understand Li Yunlong’s process of sending and receiving messages, you can basically understand the seven layers of the network above.
What are the practical applications of OSI model in network communication?
In network communication, the OSI model plays a crucial role as it not only provides a standardized and normalized basic framework for network communication, but also ensures interoperability and compatibility between different devices. It also provides guidance for network design, troubleshooting, and optimization.
1. The role of network troubleshooting: Troubleshooting is a crucial task during network operation. The OSI model provides a clear hierarchical structure that helps to quickly locate and resolve network failures. By checking layer by layer, the scope of the fault can be narrowed down and the problem can be quickly located. For example, when there is a problem with network communication, analyzing whether the transport layer protocol is working properly can determine whether it is a connection issue at the physical layer or an error in the application layer protocol, and thus make targeted repairs.
2. Application in Network Design and Optimization: In the network design phase, the OSI model provides engineers with a universal design framework that helps plan network architecture, select appropriate protocols, and optimize network performance. By designing a network according to the seven layer structure of the OSI model, a modular and standardized network architecture can be achieved for easy management and maintenance.
The OSI model, as the fundamental framework for network communication, plays an important role in promoting the development and standardization of network technology. With the continuous development of the Internet, the OSI model is also evolving, such as the emergence of cloud computing, the Internet of Things and other emerging technologies, which pose new challenges and requirements for the OSI model. In the future, the OSI model will continue to play an important role in achieving efficient and reliable data transmission and control between network communications through standardization and normalization of the OSI model, promoting continuous innovation and development of network communication technology.