Basic Configuration :
The following command to configure the switch interface with voice ( vlan # )
(config-if)#switchport voice vlan ( # )
The following command from global con guration mode to enable QoS for the switch:
(config)#mls qos
The following commands to con gure the access port attached to the IP phone to trust the CoS values of the incoming 802.1Q frames
(config)#interface fastethernet 0/1
(config-if)#mls qos trust cos
The following command on the Fastethernet 0/1 interface of ASW to con gure the access port to trust only Cisco IP phones
(config-if)#mls qos trust device cisco-phone
the following command on the interface of the switch to configure the access port to instruct the attached Cisco IP phone to reset to 0 the CoS values of frames arriving from the HOST:
(config-if)#switchport priority extend cos 0
verify the configuration
show mls qos interface fastethernet 0/1
