Cisco Systems 3750E manual Configuring Cisco IP Phone Voice Traffic, 15-5

Chapter 15 Configuring Voice VLAN

Configuring Voice VLAN

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:

	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 {detect	Configure how the Cisco IP Phone carries voice traffic:
	cisco-phone [full-duplex]vlan	• detect—Configure the interface to detect and recognize a Cisco IP
	{vlan-id dot1p none untagged}}
		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—(Optional) Configure the switch to only accept a
		full-duplex Cisco IP phone.
		• vlan-id—Configure the phone to forward all voice traffic through the
		specified VLAN. By default, the Cisco IP Phone forwards the voice
		traffic with an IEEE 802.1Q priority of 5. Valid VLAN IDs are 1 to
		4094.
		• dot1p—Configure the phone to use IEEE 802.1p priority tagging for
		voice traffic and to use the default native VLAN (VLAN 0) to carry all
		traffic. By default, the Cisco IP Phone forwards the voice traffic with an
		IEEE 802.1p priority of 5.
		• none—Allow the phone to use its own configuration to send untagged
		voice traffic.
		• untagged—Configure the phone to send untagged voice traffic.
Step 5
	end	Return to privileged EXEC mode.
Step 6
	show interfaces interface-id	Verify your voice VLAN entries.
	switchport or
	show running-config interface	Verify your QoS and voice VLAN entries.
	interface-id
Step 7
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

OL-9775-02 15-5