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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
."
Advertising the voice VLAN information to IP
phones
shows the workflow of advertising the voice VLAN information to IP phones.
Figure 38 Workflow of advertising the voice VLAN information to IP phones
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 only CDP, you can configure CDP
compatibility to enable the device to advertise the voice VLAN information to IP phones through the
CDP packets.
After receiving the voice VLAN information, the IP phone automatically completes the voice VLAN
configuration.
•
If the voice VLAN configuration is based on the received LLDP-MED TLVs or CDP packets, the
IP phone will send out packets tagged with the advertised voice VLAN ID. The voice packets
will be forwarded in the voice VLAN.
For more information about configuring LLDP or CDP, see "
Configuring LLDP to advertise a
." For more information about LLDP and CDP compatibility, see
"Configuring LLDP."
•
If the voice VLAN configuration is based on the server-assigned VLAN information, the IP
phone will send out packets tagged with the advertised server-assigned VLAN ID. The voice
packets will be forwarded in the server-assigned VLAN.
For more information about advertising the server-assigned VLAN information to IP phones,
see "
Dynamically advertising server-assigned VLANs through LLDP
." For more information
about server-assigned VLANs, see
Security Configuration Guide
.
•
If the voice VLAN configuration is based on the voice VLAN information of the accessing port,
the voice traffic from the IP phone will be forwarded in the voice VLAN of the accessing port.
Whether the voice packets are tagged depends on the voice VLAN configuration of the
accessing port. For more information about configuring a voice VLAN on a port, see
"