1. Data link layer function
The error response of the frame is to check your data frame.
Two.MAC address
Your MAC address has a 48-bit binary number
3. Ethernet frame format, MAC address header data< br>
Preamble: Accepted and income Port, frame start and delimiter: the computer recognizes the binary language through this start and end,
Destination address: the MAC address you sent to others’ host, source address: the MAC address of your own host, data: your application layer data. Frame check sequence: Check whether your data frame is complete.
4. Introduction to the equipment of the switch
Layer two: data link layer, layer three: network layer, these series look at the beginning letters, the bigger the better.
Second model: Yes 24 ports, dual media: both optical fiber and electrical signals, gigabit network speed.
5. Switch principleFirst of all, we The host A needs to transmit data to host B through the switch. A new switch does not know anything. Host A needs to broadcast and transmit its own data frames to each port, including your source MAC address and host B’s MAC address. At this time, the switch will learn to record the source address and port 1 of your host A in the entry. When Host B saw that this was my MAC address, he immediately responded, sending out his source address and the MAC address of Host A. At this time, the switch started learning again, and recorded the source MAC address and port of Host B in the entry. , At this time, the two hosts are transmitting data through the switch. Why do we need to use a switch: A host connected to a line can only communicate with one host for data transmission, and with a switch, multiple hosts can communicate with each other for data transmission.