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14-4
Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 14 Configuring Voice VLAN
Configuring Voice VLAN
Configuring Ports to Carry Voice Traffic in 802.1Q Frames
Beginning in privileged EXEC mode, follow these steps to configure a port to carry voice traffic in
802.1Q frames for a specific VLAN:
To remove voice VLAN, use the no switchport voice vlan interface configuration command or the
switchport voice vlan none interface configuration command.
Configuring Ports to Carry Voice Traffic in 802.1P Priority-Tagged Frames
Beginning in privileged EXEC mode, follow these steps to configure a port to instruct the IP phone to
give voice traffic a higher priority and to forward all traffic through the native VLAN.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
mls qos
Enable QoS for the entire switch.
Step 3
interface interface-id
Specify the interface connected to the IP phone, and enter interface
configuration mode.
Step 4
mls qos trust cos
Classify ingress traffic packets with packet CoS values. For untagged
packets, use the port default CoS value.
Step 5
switchport voice vlan vlan-id
Instruct the Cisco IP Phone to forward all voice traffic through the specified
VLAN. By default, the Cisco IP Phone forwards the voice traffic with
an 802.1Q priority of 5.
Valid VLAN IDs are from 1 to 4094.
Step 6
end
Return to privileged EXEC mode.
Step 7
show interfaces interface-id
switchport or
show running-config interface
interface-id
Verify your voice VLAN entries.
Verify your QoS and voice VLAN entries.
Step 8
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
mls qos
Enable QoS for the entire switch.
Step 3
interface interface-id
Specify the interface connected to the IP phone, and enter interface
configuration mode.
Step 4
mls qos trust cos
Classify ingress traffic packets with packet CoS values. For untagged
packets, use the port default CoS value.
Step 5
switchport voice vlan dot1p
Instruct the switch port to use 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 802.1P priority of 5.
Step 6
end
Return to privileged EXEC mode.