Hi
Nothing happens if you keep it as allowed.
If you configure as required , first check the device datasheet to make sure it supports.
"
WMM
Enable WMM on a WLAN in order to create the simplest implementation of QoS; this option is on the QoS tab in the WLAN configuration menu. Other WMM policy settings are:
- Disabled - WMM is not in use on the WLAN.
- Required - Clients must support WMM or they are not permitted to access the WLAN.
- Allowed - Clients that support WMM may use it, while those that do not support WMM can still connect to the network. "