Teach you to understand the communication protocol in three minutes

Once you enter the communications industry, you will find that no matter what position you are in, you cannot avoid "protocols".

The senior experts kept talking:

“You must learn the protocol well”

"If there is a problem, read the agreement"

"The implementation does not conform to the protocol"

......

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What exactly is a protocol? Why do people emphasize the importance of protocols? What are the things to pay attention to when studying protocols? Today, the editor will give you a brief introduction to the relevant content.

Whether you are a newcomer in the communications field who is still confused about protocols, or an experienced person who has already used protocols to solve engineering problems with ease, I hope this article will be helpful to you.

01. What is the agreement?

A protocol in a narrow sense is a network protocol, which is a set of agreements that both communicating computers must follow, such as how to establish a connection, how to identify each other, etc. Only by complying with the agreement can computers communicate with each other.

In a broad sense, technical specifications and technical reports organized by various industries, national standards, and specific business signaling processes can all be called "protocols."

In addition to "protocol", we often hear "specifications" and "standards". The connection and difference between them can be seen in the figure below.

There are thousands of standardization and industry organizations in the industry, including international ones such as ITU and 3GPP, and national ones such as CCSA in China and ETSI in Europe. Here we take 3GPP as an example, which is also one of the organizations we come into contact with most in our daily work.

(The "Agreement" mentioned below refers to the agreement in a broad sense.)

02. Why learn about protocols?

Of course, it is because it is important! Although it is a repetitive saying, it is also true. The importance of the agreement is reflected in its authority, timeliness and fundamentality.

Authority is reflected in the authority of the publisher and the content. Those who can publish agreements are mainstream associations or institutions in the industry, and the content covers all communication-related issues such as radio access network (RAN), core network & terminal (CT), service & system (SA), etc.

Timely release and update are timely. New versions can be obtained at the first time, and they are constantly updated according to version evolution to ensure the continuity and direction of technological development.

The foundation is reflected in the fact that the protocol, as an industry standard, provides a basic consensus and also provides some optional options.

In a word, just read the classics and learn.

03. How to learn the protocol

Different positions require different personalized guidance, but the editor also has some common experiences (pitfalls) to summarize.

A good method is half the success. What everyone is more likely to get access to is the 3GPP technical specification (TS), so let’s start from here.

1) Get the agreement text directly from the official website

Taking 3GPP as an example, the official website is open to everyone through shared FTP and can be reached by visiting the following link.

https://www.3gpp.org/ftp/Specs/archive/

2) Understand attribution, versioning, and content

Different specifications have different series, for example, 4G is series 36 and 5G is series 38. Protocol naming follows certain coding standards.

The specifications that have been solidified for a period of time will have a frozen version, which is called a Release. There are also minor version updates in each Release. Usually we can just download the latest version.

3) Pay attention to the directory structure and abbreviations of the protocol

Technical specifications are divided into two types: overview protocols (such as TS 23.501) or specific functional protocols (such as TS 32.251). Taking the system architecture of TS 23.501 5G system of 5G core network as an example, the following is the directory structure of the protocol.

4) Make good use of electronic version of the query

A senior expert once told me that the agreement is not for reading, but for checking. I, who had just joined the company, didn't quite understand it at the time. I prepared a paper version and worked hard for several nights, but achieved little results.

As the work progresses, I also encounter situations where I need to look up a certain knowledge point in the agreement. At this time, the electronic version is very convenient to query.

An agreement may contain hundreds of pages, but the specific content used is only a certain item on a certain page. Therefore, being familiar with the directory and making good use of search will achieve twice the result with half the effort.

Finally, I would like to say a few more words.

When learning protocols, don't be afraid of difficulties, and don't try to get everything done in one go. After reading the architecture overview, choose the parts you need to read carefully. It is a long process to understand them thoroughly. I hope everyone can gain something and become a giant in communications. Come on, everyone.