Shulou(Shulou.com)06/01 Report--

How does the Internet work?

Text keywords: Internet, network operator, router, request response

This article in order to help you understand that abstract concepts have been omitted, and there will be imprecation, please ignore.

People have been using the Internet for a long time, but if you need to learn relevant knowledge, you will find that you don't know how it works. First of all, the Internet can make the machines connected to the network communicate with each other, no longer an isolated individual, and can meet our needs through a variety of websites, applications and games. So, since computers all over the world can be connected to each other through the Internet, there may be billions of them in total, so how did such a huge online empire be built?

Usually we manage the major network operators by region to provide services for us, and everyone follows a unified standard.

When we first come into contact with the Internet, we may all have a question about who is maintaining the entire Internet and who connects computers around the world. In fact, this problem is like laying railways and building signal base stations, when we use a unified standard to complete the most basic facilities in different countries, different cities, and different regions, when every local location is completed, then the entire Internet empire will be born. When the location of the user changes, what will change is where to access the Internet and who will provide the service.

The figure above is a simplified network level diagram, which only shows personal PC, network operator and public network server. We do not discuss the underlying network data sending and receiving.

When we operate with different software, the overall process may be slightly different, but it can be simply divided into two stages to send a request and get a response. First of all, Guangdong pretty boy should use Baidu search engine to check the information.

Then opening the website and seeing the web page is a complete process. Starting from the personal PC, through layers of routers, an instruction is sent out until the network operator (that is, the broadband and optical fiber we use) does not really submit this request to the Internet, and then will find the public network server according to the given URL and return the entire content of the page together with all kinds of data.

two。 Next, Guangdong pretty boy will send the collated data to Brother 13 in Heilongjiang, who is in charge of the head office through QQ.

When we use one software to send a message or file to another person (except the local area network software), it is processed by the public network server. Handsome boy's file is not sent directly to the 13 elder brother's computer, but through the QQ server, that is to say, handsome boy can only get a successful response, at this point, his network behavior is over. At the same time, 13 will receive messages or file data sent by the QQ server, and will also send a message that has been successfully received to the QQ server after successfully receiving the file.

The above series of operations are done by QQ software to help us control the network behavior and easily achieve the functions we need, just to explain that the computers of two people are not directly connected, but are handled through the Internet.

3. Brother 13 in Heilongjiang sent a multinational email to Peter in Texas after generating the product plan based on the data.

At this time, we should all know that this action is done by our mail service providers (such as NetEase, GMail, etc.). This process still goes through layers of routers and finally arrives at the public network server that provides mail services. as it is transnational mail, it may involve the replacement of operators, but who cares? This does not affect the communication of the entire network, because we are an empire built in accordance with unified communications standards.

4. John in New York sent a Twitter and circled Peter.

In fact, whether it is PC surfing the Internet through the network, or mobile phone access to the network, the whole process is the same, the difference is only the operators and each layer of data processing. In addition, all kinds of applications have been developed in order to optimize the user experience. If Peter is using a web app, he will only see a new message when he opens the page, while if he is using a mobile app, he will usually receive a message pushed directly from the server (the principle is similar to QQ).

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