Automatically identifying IP phones through LLDP
When you use OUI addresses to identify IP phones, the number of OUI addresses that can be configured
is limited. Additionally, when there are plenty of IP phones in the network, you must configure many OUI
addresses. If your IP phones support LLDP, you can configure LLDP to automatically identify IP phones. For
more information, see
Configuring a device to advertise voice VLAN
information to IP phones
How a device advertises voice VLAN information
When an IP phone supports LLDP, the device can advertise the voice VLAN information to IP phones
through the LLDP-MED TLVs.
When an IP phone supports CDP rather than LLDP, you can configure CDP compatibility to enable the
device to advertise the voice VLAN information to IP phones through the CDP packets.
For more information about LLDP and CDP compatibility, see "Configuring LLDP."
How a device obtains voice VLAN information
Configuring a voice VLAN on ports. For more information, see
•
port."
When an IP phone cooperates with the authentication function, the server-assigned VLAN
•
information can be advertised to the IP phone. For more information, see
server-assigned VLANs through
Configuring LLDP to advertise the specific voice VLAN information. For more information, see
•
"Configuring LLDP to advertise a specific voice
Figure 47
shows the order of the three methods.
Figure 47 Workflow of advertising voice VLAN information to IP phones
"Enabling LLDP to automatically discover IP
LLDP."
147
phones."
"Configuring a voice VLAN on a
VLAN."
"Dynamically advertising