Users Guide

744 VLANs
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 MAC-based and auto mode 802.1X authentication on ports
configured for Voice VLAN in general 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. 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 MAC-based and auto mode. In both MAC-
based and auto modes, voice packets are identified by the VoIP device source
MAC address. MAC-based mode supports multiple VoIP devices. Auto-mode
supports a single VoIP device.
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.
Authentication of Voice Devices
Switch ports can be configured to use either IEEE 802.1X MAC-based or
port-based authentication. If authentication is enabled, the voice device must
be authenticated into the configured Voice VLAN by the RADIUS server
sending an Access-Accept message indicating the device is a voice device. If
the switchport voice vlan override-authentication option is configured, any
device may access the Voice VLAN regardless of the 802.1X port
authentication state.
NOTE: Voice VLAN must be configured on general or access mode ports. It is not
supported on trunk mode ports.