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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 "
Enabling LLDP to automatically discover IP phones
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 "
How a device obtains voice VLAN information
•
Configuring a voice VLAN on ports. For more information, see "
•
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 LLDP
•
to advertise the specific voice VLAN information. For more information, see
Configuring LLDP to advertise a specific voice VLAN
."
shows the order of the three methods.
Figure 50
Workflow of advertising voice VLAN information to IP phones