Users Guide

Layer 2 Switching Commands 896
User Guidelines
Enable voice VLAN using the following steps:
• Create one or more voice VLANs on the switch.
• Configure the interface in access or general mode.
• Enable voice VLAN globally and add a voice VLAN on the desired
interfaces.
• Optionally configure 802.1X MAC or port-based authentication on the
interface and globally.
If using MAC based authentication, also:
• Configure one or more RADIUS servers on the switch.
• Configure the RADIUS servers to send the VSA traffic-class = voice in the
Access-Accept.
• Enable 802.1X authentication on the phone.
• Ensure the IP phone connected ports are configured in general mode.
• Optionally enable critical voice VLAN.
If using auto authentication:
• Optionally configure the interface to override authentication. If
authentication is not overridden, the IP phone must authenticate using
802.1X.
Voice VLAN may be configured on general or access mode ports. It is not
supported on trunk mode ports.
Use the switchport voice vlan vlan-id command to enable voice VLAN on an
interface.
Voice VLAN information is transmitted to the phone via LLDP-MED in the
Network Policy TLV (Application Type Voice, Tagged Yes, …). Voice VLAN
information is transmitted to the phone via CDP in the Appliance VLAN
TLV. The voice VLAN must be configured on the switch and must be
different than the data VLAN. The configured or default priority is sent to
the phone Class of Service (CoS) TLV. The trust status is sent to the phone
via CDP in the Extended trust TLV. The configured or default priority/DSCP
is sent to the phone via LLDP in the MED TLVs. LLDP and CDP packets are
exchanged regardless of the 802.1X authentication state.