On WLANs where many users exist, such as in high density scenarios, as the number of online users increases users compete fiercely to occupy channels. As a result, network quality deteriorates. To ensure online users' network access, configure the user Call Admission Control (CAC) function. User CAC allows an AP to control user access based on the thresholds specified according to the number of online users, or terminal SNR, which enables high-quality network access services.
CAC uses two types of thresholds to control access of new users and roaming users respectively. When a new user connects to the AP, the AP checks whether the number of online users reaches the threshold set for new users. If so, the AP denies the new user access and hides its SSID to prevent new users from accessing WLAN services provided by the radio. To ensure that online users of another AP can roam to the current AP, some resources are reserved for roaming users. However, too many users roaming to the AP deteriorated online users' experience of the AP. Therefore, a CAC threshold for roaming users is required. When a user roams to an AP, the AP accepts them provided the number of users on the AP does not reach the CAC threshold for roaming users.
Based on the number of users:
Based on the terminal SNR
SNR-based UAC controls access from weak-signal users, and is applicable to scenarios where the WLAN has good signal coverage and weak signals only at the edge of WLAN coverage areas.
When receiving a new access request, the AP checks whether the terminal SNR reaches the threshold specified for new users. If so, the user is denied access. If not, the AP allows the user to go online.