Network performance issues

The upstream router of the switch is directly connected to the terminal normally, but the network speed slows down after connecting to the switch.

Possible reasons: Improper setting of switch port speed; Poor or excessively long network cable quality; Too many devices are connected to the switch; The switch has enabled extension mode.
Solution: Check and adjust the port speed settings of the switch and router; Replace the high-quality network cable and control the length of the network cable; Reduce the number of devices connected to the switch to avoid broadcast storms; Turn off the extension mode of the switch.