Users Guide

Table Of Contents
794 VLANs
A RADIUS-assigned VLAN may be used to carry voice traffic. The voice
VLAN must be preconfigured on the switch. The RADIUS-assigned voice
VLAN need not be the same as the voice VLAN configured on the interface.
If no voice VLAN is configured on the interface, the RADIUS-assigned voice
VLAN is ignored, a log message is generated, and the phone is not
authenticated on the network.
The Voice VLAN feature can be enabled on a per-port basis. Voice VLAN
supports a configurable voice VLAN DSCP or IEEE 802.1p value. This value
is transmitted by LLDP when the LLDPDU is transmitted, if LLDP has been
enabled on the port, the DSCP/802.1p value is configured, and the LLDP
network policy TLV has not been suppressed for the port. LLDP-MED is
enabled by default on all ports.
Voice VLAN is supported on ports configured in access mode or in general
mode. Both multi-domain and multi-domain-multi-host authentication is
supported on ports configured for Voice VLAN in switchport general or access
mode. Only auto mode authentication is supported for Voice VLAN-enabled
ports configured in access mode. A single voice device can authenticate into
the voice VLAN when the port is configured in access mode. Additional voice
device authentications are ignored. Only a single operational voice VLAN is
supported on a port at any time. Voice VLAN is not supported on trunk mode
ports, although a trunk mode port may be a member of the Voice VLAN.
Identifying Voice Traffic
Voice VLAN operates in both multi-domain and multi-domain-multi-host
host modes. In both modes, voice packets are identified by the VoIP device
source MAC address. Both multi-domain and multi-domain-multi-host
support a single VoIP device using a single voice VLAN.
Voice VLAN is supported on ports configured in access mode and in general
mode. Voice VLAN is not supported on trunk mode ports, although a trunk
mode port may be a member of the voice VLAN.
NOTE: Voice VLAN must be configured on general or access mode ports. It is not
supported on trunk mode ports.