Ethernet switch is the most common application, the price is also cheaper, the grade is complete. Therefore, the application field is very extensive, in the large and small LAN can see their traces. Ethernet switches typically have several to dozens of ports, essentially a multiport network bridge. In addition, its port rate can be different, the work can also be different, such as can provide 10M, 100M bandwidth, provide Half-duplex, Full-duplex, adaptive working methods.
The Ethernet switch works on the second layer of the OSI Network Reference Model (that is, the data link layer), which is a network device based on MAC (media access control, media access controls) address recognition, and complete Ethernet data frame forwarding.
A socket on a switch used to link a computer or other device is called a port. The computer uses a network card to connect to the port on the switch. Each port of the NIC, switch, and router has a MAC address, which is solidified by the device manufacturer in the eprom of the device. The Mac is assigned by the IEEE and each MAC address is the only one in the world. The MAC address is a 48-bit binary, the first 24 digits are the device manufacturer identifier, and the last 24 digits are assigned by the manufacturer.
The switch accepts the data frame sent by the computer on the port, finds the MAC address table according to the destination MAC address of the frame head, and then forwards the data frame from the corresponding port to realize the data exchange.
The working process of the switch can be summarized as "learning, memory, receiving, look-up, forwarding" and so on: the MAC address of the device connected to each port through "learning", and the corresponding relationship between the MAC address and the port number "memory" in memory, production MAC address table; After receiving to the data frame from a port, find the port number in the MAC address table that corresponds to the destination MAC address in the frame header, and then "forward" the data frame from the detected port.
The switch splits the conflict domain, and each port is a separate conflict domain. If a large amount of data is sent to each port, the port will first store the received data in the register and send it when it is sent.