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Catalyst 3560 Switch Software Configuration Guide
OL-8553-06
Chapter 15 Configuring Voice VLAN
Configuring Voice VLAN
This example shows how to configure a port connected to a Cisco IP Phone to use the CoS value to
classify incoming traffic, to use IEEE 802.1p priority tagging for voice traffic, and to use the default
native VLAN (VLAN 0) to carry all traffic:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# mls qos trust cos
Switch(config-if)# switchport voice vlan dot1p
Switch(config-if)# end
To return the port to its default setting, use the no switchport voice vlan interface configuration
command.
This example shows how to enable switchport voice detect on a Cisco IP Phone:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface fastethernet 0/1
Switch(config-if)# switchport voice?
detect detection enhancement keyword
vlan VLAN for voice traffic
Switch(config-if)# switchport voice detect?
cisco-phone Cisco IP Phone
Switch(config-if)# switchport voice detect cisco-phone?
full-duplex Cisco IP Phone
Switch(config-if)# switchport voice detect cisco-phone full-duplex
full-duplex full duplex keyword
Switch(config-if)# end
This example shows how to disable switchport voice detect on a Cisco IP Phone:
Switch# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface fastethernet 0/1
Switch(config-if)# no switchport voice detect cisco-phone
Switch(config-if)# no switchport voice detect cisco-phone full-duplex
Configuring the Priority of Incoming Data Frames
You can connect a PC or other data device to a Cisco IP Phone port. To process tagged data traffic (in
IEEE 802.1Q or IEEE 802.1p frames), you can configure the switch to send CDP packets to instruct the
phone how to send data packets from the device attached to the access port on the Cisco IP Phone. The
PC can generate packets with an assigned CoS value. You can configure the phone to not change (trust)
or to override (not trust) the priority of frames arriving on the phone port from connected devices.
Beginning in privileged EXEC mode, follow these steps to set the priority of data traffic received from
the nonvoice port on the Cisco IP Phone:
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify the interface connected to the Cisco IP Phone, and enter interface
configuration mode.