Hello everyone, today we will talk about the core network.
Friends who have been following Xiaozaojun for a long time must know that I am a typical "core network phobia" patient. For a long time, I have been instilling a thought for everyone, that is--
Everyone read the articles I wrote, from base stations to mobile phones, from satellites to submarine cables, it can be said to cover all fields of communication, but only the core network is rarely involved.
In fact, I am a core network engineer with a serious and well-established roots. I have worked in the Z company for eleven years and have always been under the core network department.
The reason why a veteran driver like me refuses to write about the profession he is best at is because even with my ten-year practice, it is difficult to put it in a straightforward and easy-to-understand manner.
But today, I am really forbearing (zi) without (xun) but (si) forbearing (lu), and decided that the overlord would go to the bow, and I will do a topic of the core network for everyone——
Entering the topic, first of all, what is the core network?
The English name of the core network is Core Network, or CN for short. Well, yes, it is the same as the English abbreviation of our great motherland.
Regarding the definition of the core network, you must not read Baidu Encyclopedia. The statements in it are either nonsense. If you say it, you don’t say it, or it’s not human, and you don’t understand it at all.
How should we define it?
To be honest, so far, I haven't seen any satisfactory answer.
It's not that I'm making mysticism, but the concept is really difficult to define-if it is interpreted from a broad perspective, it is difficult to delimit the boundary, if it is interpreted from a narrow perspective, there is no one entity that accurately corresponds to it.
It is actually a collection, a collective term for many "devices with specific functions".
In order to facilitate understanding, you can regard the core network as a "very complex enhanced router."
The three major components of the communication network: access network, bearer network, and core network.
The access network is the "window" and is responsible for receiving data; the bearer network is the "truck", which is responsible for sending data back and forth; the core network is the "management hub", which is responsible for managing these data and sorting data. Then tell it where to go.
The processing and distribution of data is actually "routing and switching", which is the essence of the core network.
Therefore, if you are determined to engage in the core network, congratulations, "Electromagnetic Fields and Electromagnetic Waves" can be thrown away! However, please go to the computer next door and borrow a copy of "Computer Network (Top-Down Method)".
The complexity of the core network is actually man-made. To be more specific, it is because of the needs of the market. Users generate desires, and the market creates desires. The more desires, the more needs, and the more needs, the more businesses. The more services, the more devices, the more interfaces, and the more complex the network.
The whole communication is the sameIn the earliest days, the core network of the fixed telephone network, to put it bluntly, was to connect the telephones at both ends of the wires. This kind of exchange was very simple.
Later, the number of users increased, the network range became larger and larger, and layers began to emerge.
The network architecture is also complicated, with network elements. A network element is a Net Element (NE for short), which is a network element entity with a certain function.
At the same time, we need to identify and manage users-not all users are allowed to use this communication network. Only authorized legal users can use it.
As a result, a bunch of devices (network elements) related to users are added. In short, their core tasks are only three: authentication, authorization, and accounting.
Authentication depends on whether you are a legitimate user and whether you have a key.
Authorization depends on what you have permission to do, which services can be used, and which cannot be used.
Keeping accounts means seeing what you have done, then recording it and collecting your money.
Later, with wireless communication, the way to connect users changed, from telephone lines to radio waves, and wireless access networks were born. When the access network has changed, the core network will also change, so there is a wireless core network.
Later, there were 2G, 3G, and 4G.
Each generation of communication standards and each specific standard has its own network architecture, its own hardware platform, its own network elements, and its own equipment.
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