Standard Internet communication protocol-TCP/IP protocol

Today, let's talk about the standard Internet communication protocol-TCP/IP protocol.

This part of content may not be very understandable and abstract. It is a tough nut for beginners, but since it is a beginner, don't let everyone have any mental burden. No one is a genius, right? I will try my best to give you more examples for your understanding!
1. Basic Content

TCP/IPTransmission Control Protocol/Internet Protocol short name, Chinese translation for the Transmission Control Protocol/Internet Protocol) Protocol is the most widely used network communication Protocol, it is also the standard connection protocol for the Internet. It provides a complete set of protocols that are convenient and practical and can be applied to a variety of networks, making network interconnection easy, and adding more and more networks to it has become a de facto standard for the Internet.
Specifically, TCP/IP is a set of protocol groups, including TCP, IP, and other protocols.
Therefore, we must make it clear that the TCP/IP protocol not only represents the TCP protocol and the IP protocol, but also represents a group of protocols. Other protocols in the protocol group are also very important. As for what protocols are included, don't worry. I will tell you later!
2TCP/IP protocol generation
What is the TCP/IP protocol? Let me briefly introduce it to you:
The Chinese meaning of Internet is "Internet", which is actually a "network between networks (Internet)" formed by connecting local networks around the world )".
The prototype of the Internet is ARPANET, a military network. before the formation of the Internet, many small local networks have been established in various parts of the world. However, these various local networks have different network structures and data transmission rules, to connect these local networks, you must have a unified rule for data transmission, namely, the TCP/IP protocol.
What? I still don't understand. Well, let me give you an example. For example, if people from all over the world need to communicate with each other, they must use a unified language. Currently, they are in English) the same applies to communication and communication over the Internet. to connect all computers for communication, a unified data transmission standard (CP/IP Protocol) is required.
Only computers that comply with this protocol can join the Internet family to transfer data with other computers and communicate with other computers. That's it. Do you understand?
3. layer-4 Model

We have known from the above that there are many protocols in the TCP/IP protocol group, so what is the relationship between these protocols? Protocols in TCP/IP protocol groups are not distributed in a plane, but distributed in layers. They follow a four-layer model concept: application layer, transport layer, and Interconnection layer) and network interface layer.
Application Layer: it defines the procedures for applications to use the Internet, and applications will access the network through this layer. The application layer is a general term for all applications that users are targeting. The ICP/IP protocol family has many protocols at this layer to support different applications. The implementation of Internet-based applications that many users are familiar with is inseparable from these protocols.
For example, we use the HTTP protocol, FTP protocol for file transmission, SMTP for email sending, DNS protocol for domain name resolution, and Telnet protocol for remote login for WWW access, all belong to the TCP/IP application layer. In terms of users, most of the graphic operation interfaces built by software are displayed, and the actual backend runs the above protocols.
Transport Layer: establishes, manages, and removes reliable and effective end-to-end connection protocols between two user processes, that is, responsible for the communication from the start point to the end point. this layer provides communication between applications. Including TCP transmission control) and UDP user datagram.
Interconnection layer: This layer defines the "Information Package" format transmitted over the Internet, and the "Information Package" forwarding mechanism from one or more routers to the final target. Including Internet Protocol IP address, Address Resolution Protocol ARP, Internet Control Message Protocol ICMP, and Internet Group Management Protocol IGMP. This layer is also a key layer in the TCP/IP protocol family.
Network Interface Layer: the bottom layer of the layer-4 model) is the network interface layer. Sends and receives data frames. frames are independent network information transmission units. The Network Interface Layer places frames on the Internet or retrieves frames from the Internet.
Note: The layer-5 model also includes the physical layer, that is, the hardware layer)
4. End

For details about each protocol, if I have time, I will write it for you. Due to space limitations, I will not talk about it here.
In fact, the TCP/IP protocol can be completely explained in a few words. I believe that you will encounter many problems in the future, but you have to find information by yourself, my tutorial is just an entry-level role. If you cannot satisfy the appetite of any old bird, don't blame me. After all, I showed it to cainiao.
For friends who have just come into contact with these things, I still hope that everyone will not be eager to seek success. First, there will be a concept, and the days will be long in the future. In that case, no one is a genius. Come on! The real genius is not to learn, but to learn !!

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