How does a switch work?

The working principle of the switch is to achieve this function by learning and forwarding data frames. When the switch receives a data frame, it parses the source MAC address in the data frame, associates the address with the corresponding interface, and stores this information in the internal forwarding table. The forwarding table is a very important data structure in the switch. It records the correspondence between MAC addresses and interfaces. This forwarding table is established through a learning process, that is, when the switch receives a data frame, it associates the source MAC address in the data frame with the interface that received the data frame.

A switch is a network device used to implement communication between different devices in the network. The basic principle is to achieve this function by learning and forwarding data frames. When the switch receives a data frame, it parses the source MAC address in the data frame, associates the address with the corresponding interface, and stores this information in the internal forwarding table. The forwarding table is a very important data structure in the switch. It records the correspondence between MAC addresses and interfaces. This forwarding table is established through a learning process, that is, when the switch receives a data frame, it associates the source MAC address in the data frame with the interface that received the data frame.

When the switch receives another data frame whose destination MAC address matches the record in the forwarding table, it will forward the data frame directly to the corresponding interface, thereby achieving fast data transmission. If the destination MAC address is not recorded in the forwarding table, the switch will broadcast the data frame to all interfaces to find the destination device. This process is called flooding. In addition, broadcast and multicast frames are forwarded to all ports.

Simply put, a switch functions like a post office. It is responsible for delivering data frames quickly and accurately in a complex network to ensure effective communication between various devices. By learning and forwarding data frames, the switch can automatically establish the mapping relationship between MAC addresses and interfaces, optimize the data transmission path, and improve the overall performance and stability of the network.

The core function of a switch is to connect multiple Ethernet physical segments, isolate conflict domains, and perform high-speed and transparent switching and forwarding of Ethernet frames. Specifically, after receiving the data frame, the switch will check its destination MAC address, and then forward the data frame out of the interface where the destination host is located. This process mainly relies on the MAC address table inside the switch, which records the corresponding information between all MAC addresses in the network and each port of the switch.

First, the switch establishes the mapping relationship between the address and the switch port in the MAC address table based on the source MAC address in the data frame, and writes it into the MAC address table. In this way, when the switch receives another data frame whose destination MAC address matches the record in the MAC address table, it can directly forward it to the corresponding interface, improving the efficiency of data transmission.

Secondly, if the switch receives a data frame with a destination MAC address that is not in the MAC address table, it will flood the data frame to all ports in order to find the destination device. This process is called flooding. In addition, broadcast and multicast frames are forwarded to all ports.

In addition to the above basic functions, modern switches also have some advanced functions, such as VLAN division, link aggregation, spanning tree protocol, etc. These features further enhance the performance and flexibility of the switch, enabling it to better meet a variety of complex network requirements.

In general, switches play an important role in the network. They can provide high-speed and efficient data transmission services and ensure the stability and availability of the network. In the future, with the development of technology and the continuous growth of network requirements, switches will continue to play an important role in promoting the progress and development of network technology.

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