Cisco 8800 Series Deployment Manual page 54

The WMM policy should be set to Required only if the Cisco IP Phone 8800 Series or other WMM enabled phones will be
using this SSID.
If there are non-WMM clients existing in the WLAN, it is recommended to put those clients on another WLAN.
If non-other WMM clients must utilize the same SSID as the Cisco IP Phone 8800 Series, then ensure the WMM policy is set to
Allowed.
Enable 7920 AP CAC to advertise Qos Basic Service Set (QBSS) to the client.
Cisco IP Phone 8800 Series Wireless LAN Deployment Guide
54