Administrator Guide

VLANs 753

Configuring a Voice VLAN (Extended Example)

The commands in this example create a VLAN for voice traffic with a VLAN

ID of 25 using an IP phone that does not support 802.1X authentication. Port

gi1/0/10 is set to an 802.1Q VLAN. In this example, there are multiple devices

connected to port gi1/0/10, so the port must be in general mode in order to

enable MAC-based 802.1X authentication. Next, Voice VLAN is enabled on

the port with the Voice VLAN ID set to 25. Finally, Voice VLAN

authentication is disabled on port gi1/0/10 because the phone connected to

that port does not support 802.1X authentication. All other devices

connected to the port are required to use 802.1X authentication for network

access. For more information about 802.1X authentication, see "Port and

System Security " on page 623.

This example shows the configuration for a switch with directly connected IP

phones. The interior of the network will still require configuration of QoS on

the selected voice VLAN in order to ensure service.

To configure the switch:

Create the voice VLAN.

console#configure

console(config)#vlan 25

console(config-vlan25)#exit

Enable the Voice VLAN feature on the switch.

console(config)#voice vlan

Configure port 10 to be in access mode.

console(config)#interface gi1/0/10

console(config-if-Gi1/0/10)#switchport mode access

Enable MAC-based 802.1X authentication on the port. This step is

required only if there are multiple devices that use 802.1X authentication

connected to the port. The authentication server will need to be

configured with the MAC address of the IP phone.

console(config-if-Gi1/0/10)#dot1x port-control mac-based

NOTE: In an environment where the IP phone uses LLDP-MED to obtain

configuration information, an additional step to enable LLDP-MED on the

interface would be required by issuing the lldp med command in Interface

Configuration mode.