Explain the five major network concepts in a vivid and interesting way

The update of 5G technology has promoted the development of a new generation of network communications. Home broadband Internet access has also increased from the initial speed of more than ten kilobits to the current speed of hundreds or even thousands of megabits. Many users who have deployed home NAS have even updated their internal LAN to a 10G level.

In this information interconnected age, although not everyone needs to learn network technology, everyone should still master some basic network knowledge so that they can help themselves at critical moments. Now I will start with an interesting explanation of the basic concepts of the network, striving to make it simple and easy to understand, without giving any professional and technical explanations.

When it comes to the Internet, there are five basic concepts that must be mentioned: IP address, subnet mask, gateway, DHCP service and PPPoE dial-up. These are frequently used in daily computer or router network configuration. I believe many people have heard of these concepts and know that they are just strings of numbers, but they are not clear about what they are and what they are used for. Next, we will explain these five basic network concepts.

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What is an IP address?

First, let me ask you a question. If there is a group of people in a closed room, how can you quickly call someone? I believe your first reaction is to call the name, right! At the same time, there is also a simple way, which is to give each person a number. For example, when number one is called, you will know who it is.

The same is true in the network world. To quickly access a device, each device needs a number, and this number is the IP address of the network device. In this room, if two people have the same number, what will happen? When this number is called, no one knows who is being called. Therefore, two people with the same number are not allowed in a room, and two devices with the same IP address are not allowed in a local area network. If there is an IP conflict, it will seriously endanger the stability of the network.

Let's expand on this. In a building, there are many such closed rooms, and each closed room has a group of people. So how do we locate a person in a certain room?

The answer is definitely numbering. Give each room a number, for example, No. 1 in room 1, so that we can locate a specific person. At this time, we also add the room number to the person's number. The room number and the person's number are separated by a ".", for example, No. 1.1, which means that this person is No. 1 in room 1.

The same is true for the IP addresses in network devices. For example, 192.168.1.100 can be understood as room 192.168.1, which is the network segment we will mention, and 100 is the device numbered 100 in this network segment.

What is a subnet mask?

According to the numbering mentioned above: 192.168.1.100, a new question arises: why is the room number: 192.168.1, and the person number is 100? Can the room number be set to 192.168 and the person number to 1.100?

The answer is of course yes, but this setting will cause a problem. The number 192.168.1.100 will be ambiguous. It can represent person No. 100 in room 192.168.1, or person No. 1.100 in room 192.168. At this time, another rule must be introduced to tell people which number is the room number and which number is the person's number, and this rule is the subnet mask.

We all know that online time is the digital world, so this rule is designed to be very pleasing. The length is set to the same as the number, and through the operation with the number, people are finally told which are the room numbers and which are the people's numbers.

The specific calculation is too complicated, so here we use the simplest way to explain it. For example: the subnet mask is 255.255.255.0. The most commonly used rule means that the first three digits of 255.255.255 are the room number, and the last digit 0 is the person number. For example, the IP address 192.168.1.100 and the subnet mask 255.255.0.0 indicate that 192.168 is the room number, that is, the network segment, and 1.100 is the person number, that is, the number of the device in this network segment.

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What is a Gateway?

Continuing with the above question, a group of people are in a closed room, and each person has a number, which is the IP address in the network device. Then the demand is upgraded at this time, and the people in the room need to communicate with the people outside the room. What should they do at this time? They need a superpower who can pass through walls to act as a microphone, shuttle around in the room, transmit the words of the people in the room to the outside, and transmit the responses of the people outside back to the people in the room.

This person with superpowers is the gateway in the network world. He is responsible for transmitting information from the internal network to the external network and transmitting information from the external network back. For a home network, isn’t this role exactly our router?

The router is the only device that connects to the broadband. All the devices in the home must go through the router to connect to the broadband and surf the Internet. So the gateway is the router in our home broadband network. If the gateway is set incorrectly, it is like you send the words you want to send to a person without super powers, and naturally you cannot send the words outside the room.

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What is DHCP service?

After understanding the above, we can know how important a person's number is. If it is a room with several people, then it is still very easy to assign numbers. Everyone can just choose a number. Imagine if it is a large room with hundreds of people. If everyone is asked to think of a number, then there will definitely be people who choose the same number, causing conflicts!

Therefore, at this time, someone with a say needs to stand up and arrange all the numbers. He does not need to choose the numbers himself, so there will be no conflicts with the same numbers. The service provided by this person can be called DHCP service.

There is a saying that those who are more capable should do more work, and the more capable they are, the more say they have. Do you remember the super-powered person we mentioned above? If we let him arrange numbers for each person, I believe everyone will be convinced. Therefore, in home broadband networks, DHCP services are generally provided by a gateway, which assigns an IP address to each device in the network.

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What is PPPoE dial-up?

Continuing with the above topic, the superpowers in each closed room become gateways, and can pass through the closed room to become a bridge for people in the closed room to communicate with the outside world. However, this is only for the rooms in a house to communicate with each other. How can the information be transmitted to a room or a person in another house?

At this time, a God who manages each house is needed. He can help transmit information to each house. That is, the super-powered people in each closed room hand over the communication information to this God, and God is responsible for transmitting it to each room. The service provided by God is similar to the home broadband service provided by telecom operators. Only through the home broadband service can we connect with the outside world, which is often called wide area network or Internet.

Of course, it is not so easy to talk to God. You need an exclusive channel. The way to establish this exclusive channel is PPPoE point-to-point communication. This is the exclusive channel for every superpower to talk to God, so you must not tell other people. It must be encrypted, otherwise there will be chaos in the world. Therefore, every conversation requires information authentication to open this channel. This is our home broadband PPPoE dial-up Internet access.

At this point, the explanation of the five basic network concepts has been completed. Do you understand?