S5#sh run int fa 0/21
Building configuration...

Current configuration : 199 bytes
!
interface FastEthernet0/21
 switchport trunk encapsulation dot1q
 switchport mode trunk
 switchport voice vlan 99
 switchport priority extend cos 1
 mls qos trust dscp
 spanning-tree portfast
end

S5#sh run | i mls
mls qos