How to Configuring Cisco IP Phone Voice Traffic

   Configuring Cisco IP Phone Voice Traffic

You can configure a port connected to the Cisco IP Phone to send CDP packets to the phone to configure the way in which the phone sends voice traffic. The phone can carry voice traffic in IEEE 802.1Q frames for a specified voice VLAN with a Layer 2 CoS value. It can use IEEE 802.1p priority tagging to give voice traffic a higher priority and forward all voice traffic through the native (access) VLAN. The Cisco IP Phone can also send untagged voice traffic or use its own configuration to send voice traffic in the access VLAN. In all configurations, the voice traffic carries a Layer 3 IP precedence value (the default is 5).

Beginning in privileged EXEC mode, follow these steps to configure voice traffic on a port:

Steps	Command	Purpose
Step 1	configure terminal	Enter global configuration mode.
Step 2	interface interface-id	Specify the interface connected to the phone, and enter interface configuration mode.
Step 3	mls qos trust cos	Configure the interface to classify incoming traffic packets by using the packet CoS value. For untagged packets, the port default CoS value is used. Note Before configuring the port trust state, you must first globally enable QoS by using the mls qos global configuration command.
Step 4	switchport  voice {detectcisco-phone [full-duplex] | vlan {vlan-id |dot1p | none |untagged}}	Configure how the Cisco IP Phone carries voice traffic: •detect—Configure the interface to detect and recognize a Cisco IP phone. •cisco-phone—When you initially implement the switchport voice detect command, this is the only allowed option. The default is no switchport voice detect cisco-phone [full-duplex]. •full-duplex—(Opti