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This article mainly introduces what the five-layer protocol architecture of computer network is, which can be used for reference by friends who need it. I hope you will learn a lot after reading this article. Next, let the editor take you to learn about it.

First of all, consider the question of why the computer network should adopt a hierarchical structure and what are the benefits of doing so. The network adopts hierarchical structure because it is very troublesome for computers to communicate with each other, and there are many things to consider. When using hierarchical structure, in order to divide a large and complex problem into several small local problems, then it is easier to study the local problem. In real life, there are also many stratified cases, such as platoon, company, battalion and so on in the army, such as the personnel structure of the boss, general manager, department manager and staff of the enterprise.

ISO/OSI and TCP/IP architecture

In order to promote the development of the world computer network, the ISO organization has put forward a famous system standard OSI. But OSI has only achieved some theoretical results, and what is really widely used in reality is the TCP/IP architecture.

OSI is clear in concept and complete in theory, but it is neither complex nor practical. On the other hand, TCP/IP has a four-layer architecture, which is divided into application layer, transport layer, Internet layer and network interface layer. But in fact, it only has the upper three layers, and the lowest network interface layer has no content. Therefore, we generally adopt a compromise approach when we learn, that is, we integrate the advantages of OSI and TCP/IP and adopt a five-layer protocol architecture.

Five-layer protocol architecture

From bottom to top, the protocols are: physical layer, data link layer, network layer, transport layer, application layer.

Physical layer: the physical layer considers how to propagate the data bit stream over the communication link connected to the computer. It needs to consider the mechanical characteristics, electrical characteristics and so on. Hubs work at the physical layer.

Data link layer: this layer mainly considers how to communicate between hosts in the same network. Our common MAC address acts on this layer. The switch operates at the data link layer, which has a common ARP address resolution protocol.

Network layer: the network layer is responsible for providing communication for hosts on different networks. The device working in the network layer is the router, which is a special host that accepts the packets sent by the host, then looks up its own routing table and forwards the stored packets to another network. The common protocols in the network layer are IP and ICMP.

Transport layer: the transport layer is responsible for the communication between two host processes. This layer has the famous TCP protocol, in addition, the UDP protocol also works at this layer.

Application layer: the task of the application layer is to complete specific network applications through the interaction between application processes. There are many protocols working in the application layer, such as http, ftp, ssh, dns, https.

To study computer network, we need to focus on the data link layer, network layer and transport layer.

Thank you for reading this article carefully. I hope the editor will share what the five-layer protocol architecture of the computer network is helpful to everyone. At the same time, I also hope that you can support us, pay attention to the industry information channel, and find out if you have any problems. detailed solutions are waiting for you to learn!

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