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By default, if a voice VLAN is configured on the port connected to the IP phone, the device advertises
this voice VLAN to the IP phone. The device learns the MAC address of the IP phone and increases
the priority for voice packets. The address learning is implemented in software.
In an IRF fabric, MAC address learning and synchronization of the learned MAC address entry to all
member devices in software results in an undesirable delay. In this case, you can use this feature to
configure LLDP or CDP to advertise the voice VLAN ID. Then, the IRF fabric learns and
synchronizes MAC address entries faster in hardware.
After you configure this feature, the device advertises the voice VLAN to the IP phone by following
the workflow described in
.
To configure LLDP or CDP to advertise a voice VLAN:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Layer 2 Ethernet
interface view.
interface
interface-type
interface-number
N/A
3.
Configure LLDP or CDP to
advertise a voice VLAN.
•
Configure LLDP to advertise a
voice VLAN:
lldp tlv-enable med-tlv
network-policy
vlan-id
•
Configure CDP to advertise a
voice VLAN:
a.
Specify the ID of an
advertised VLAN:
cdp voice-vlan vlan-id
b.
Configure CDP compatibility:
For more information, see
"
By default, LLDP and CDP
advertise the voice VLAN
configured on the port.
For more information about
the
lldp tlv-enable med-tlv
network-policy
command,
see
Layer 2—LAN Switching
Command Reference
.
4.
(Optional.) Display the voice
VLAN advertised by LLDP.
display lldp local-information
The advertised voice LAN
information is displayed in the
MED information
fields in the
command output.
Dynamically advertising an authorization VLAN
through LLDP or CDP
This function is available only on IP phones that support LLDP or CDP.
Dynamic authorization VLAN advertisement through LLDP or CDP works with 802.1X or MAC
authentication. If 802.1X authentication is used, make sure the IP phone support 802.1X
authentication.
After the IP phone passes authentication, LLDP advertises the authorization VLAN in the LLDP-MED
Network Policy TLV to the IP phone. If the IP phone supports only CDP, CDP advertises the
authorization VLAN in CDP packets to the IP phone. The port connected to the IP phone will be
added to the authorization VLAN.
To implement this function, perform the following configuration tasks:
1.
Enable LLDP globally and on the port connected to the IP phone.
If the IP phone supports only CDP, configure CDP compatibility on the device.
2.
Configure 802.1X or MAC authentication to ensure that the IP phone can pass security
authentication. For more information about 802.1X and MAC authentication, see
Security
Configuration Guide
.