Let's talk about network equipment

My home was recently renovated. As a computer professional, I had to get my home network equipment ready as soon as possible. First, I drew a home network architecture diagram. The most important ones are the three network devices. The optical modem is provided by the broadband provider, and the switch and wireless router are purchased by myself.

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Some friends may wonder, why do I only have a wireless router at home but no switch? What does a switch do? What is the difference between it and a router? This time I will tell you about network equipment.

Development of network equipment

Thanks to the development of technology, most of our Internet devices now support wireless Internet access, which is convenient and fast. But when computers first appeared, it was not so easy to connect multiple computers. When we only had two computers, we only needed an Ethernet cable to connect the two computers to form a network of two computers. But when a third device appears, what should we do?

Hub

In order to solve the earliest computer interconnection communication problems, the hub appeared. The hub is a device that connects multiple network cables to the same physical medium. It works on the first layer (physical layer) of the OSI 7-layer model, which means that it can be used as soon as it is plugged in. When A, B, and C are connected to the hub at the same time, a local area network of three computers is created. A can send messages to B and C. But at this time, A found several problems: First, A found that C could also receive the message he sent to B. Second, when B or C sent a message, he could not send a message. As more and more computers were involved in the hub, these two problems became more and more serious. If 20 devices are involved, one sends a message, and the other 19 devices will receive it. Everyone needs to wait until no one sends a message before they can use it, which makes everyone very annoyed. At this time, new devices appeared.

Switch

In order to solve the problems of hubs, switches came into being. Unlike hubs, switches work at the second layer of OSI (data link layer), and they have a MAC address table inside to record which port is connected to which device. When the message sent by A to B reaches the switch, the switch queries its internal MAC address table, finds the port connected to B's device by comparing the MAC address, and forwards it. In this way, C will not know the private message to B. At the same time, A will not interfere with B and C's use when sending messages, and all three people are happy.

During the use, the neighboring D, E, and F also need to join the communication. At this time, they found that the IP addresses of their subnets were different, and they could not communicate even if they connected the two switches together, which made them at a loss. Therefore, in order to solve this LAN communication problem, routers appeared.

Router

A router is a hardware device that connects two or more networks. It acts as a gateway between networks and is a dedicated intelligent network device that reads the IP address in each data packet and then decides how to transmit it. It has a built-in routing table to identify which network port the data packet accessing the IP address should be assigned to. When we need to connect our own LAN to the Internet or to someone else's LAN, we need to add a router between the two networks. The router not only has the function of routing, but is also a small switch.

The network interface of the router is divided into WAN port and LAN port. The WAN port is connected to the external network, and the LAN port is a switch of the internal network. So when there are fewer devices in our home that need to be plugged into the network cable, only one router is needed to meet the demand. When there are many devices in our home that need to be plugged into the network cable, since the switch with the same number of network ports is much cheaper than the router, we usually add additional switches to meet the demand.

After a brief introduction, you should now know what kind of network equipment you need. However, the Internet speed at home is also affected by many factors, such as: the network port speed of the optical modem, the type of network cable, the port speed of the router, etc. The wireless network speed is also affected by the number of intervening devices and signal interference. If the Internet speed at home is slow, we still have to check it bit by bit.