When there are many users in the WLAN network, such as in high-density scenarios, as the number of online users increases, the fierce competition for channels between users leads to poor Internet access quality for each user. In order to ensure the Internet access experience of online users, the user connection admission control (CAC) function can be deployed. Which of the following descriptions about the user CAC function is wrong?
A. CAC uses two thresholds to control the access of new users and roaming users respectively
B. When a roaming user accesses the radio, the roaming user can access the radio as long as the roaming user threshold is not reached
C. When most users use the same service type and the service traffic is average, it is recommended to use the user CAC function based on terminal SNRcorrect
D. When a new user accesses, the AP checks whether the current number of users or the terminal signal-to-noise ratio reaches the threshold for new users