VoIP call admission control prevents any single AP from becoming congested with voice calls.
CAC profile on controller would help us to avoid congestion.
VOIP call capacity is configured by default as 10 which define the number of calls per AP.
However handoff reservation configured by default as 20% which would reserve or prevent phones connecting more than 8, as the other 2 would be used for roaming.
Below commands would help us to configure it.
wlan voip-cac-profile <profile>