Translation

English
Networked applications do not exchange random messages. In order to ensure that the server is able to understand the queries sent by a client, and also that the client is able to understand the responses sent by the server, they must both agree on a set of syntactical and semantic rules. These rules define the format of the messages exchanged as well as their ordering. This set of rules is called an application-level `protocol`.
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Networked applications do not exchange random messages. In order to ensure that the server is able to understand the queries sent by a client, and also that the client is able to understand the responses sent by the server, they must both agree on a set of syntactical and semantic rules. These rules define the format of the messages exchanged as well as their ordering. This set of rules is called an application-level `protocol`.
An `application-level protocol` is similar to a structured conversation between humans. Assume that Alice wants to know the current time but does not have a watch. If Bob passes close by, the following conversation could take place :
Alice : `Hello` Alice : `Hello`
Bob : `Hello` Bob : `Hello`
Alice : `What time is it ?` Alice : `Quelle heure est-il ?`
Bob : `11:55` Bob : `11:55`
Alice : `Thank you` Alice : `Merci`
Bob : `You're welcome` Bob : `Avec plaisir`
Such a conversation succeeds if both Alice and Bob speak the same language. If Alice meets Tchang who only speaks Chinese, she won't be able to ask him the current time. A conversation between humans can be more complex. For example, assume that Bob is a security guard whose duty is to only allow trusted secret agents to enter a meeting room. If all agents know a secret password, the conversation between Bob and Trudy could be as follows :
Bob : `What is the secret password ?`
Trudy : `1234` Trudy : `1234`
Bob : `This is the correct password, you're welcome`
If Alice wants to enter the meeting room but does not know the password, her conversation could be as follows :
Alice : `3.1415` Alice : `3.1415`
Bob : `This is not the correct password.` Bob : `Ce n'est pas le bon mot de passe.`

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Glossary

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String information

Source string location
../../principles/transport.rst:25
String age
4 years ago
Source string age
4 years ago
Translation file
locale/fr/LC_MESSAGES/principles/transport.po, string 7