What is the specific function? In windows, a part of reserved bandwidth is reserved for automatic updates and some background transmission programs.
In a router, the quality of qos can be divided according to the protocol and ip:
For example, Internet cafes are the main customers who play online games, so the main bandwidth is divided into protocols and ports used by games.
Qq using udp protocol, the allocated bandwidth is very small, and some people always like to download it, but they can also limit it. This is to divide the bandwidth of p2p protocol, so that even if someone downloads it in Internet cafes, it will not affect the main groups playing online games.