166
connected to the IP phone is added to the VLAN assigned to the IP phone as an tagged member and
added to the VLAN assigned to the host as a untagged member. Also, the LLDP-MED TLVs that the device
sends to the IP phone carry information about the VLAN assigned to the IP phone, so that the voice
packets sent out of the IP phone can be forwarded in the server-assigned VLAN with tags.
The EAPOL packets defined in the 802.1X protocol do not carry VLAN tags. When the server is
configured to assign a tagged VLAN to the IP phone, you must configure the port connected to the IP
phone to send 802.1X protocol packets without tags by using the
dot1x eapol untag
command.
Only 802.1X supports assigning tagged VLANs.
Figure 54
Using 802.1X to authenticate an IP phone
Displaying and maintaining voice VLAN
Task Command
Remarks
Display the voice VLAN state.
display voice vlan state
[
|
{
begin
|
exclude
|
include
}
regular-expression
]
Available in any view
Display the OUI addresses that the
system supports.
display voice vlan oui
[
|
{
begin
|
exclude
|
include
}
regular-expression
]
Available in any view
Voice VLAN configuration examples
Automatic voice VLAN mode configuration example
Network requirements
As shown in
,
•
The MAC address of IP phone A is 0011-1100-0001. The phone connects to a downstream device
named PC A whose MAC address is 0022-1100-0002 and to Ethernet 1/0/1 on an upstream
device named Device A.
•
The MAC address of IP phone B is 0011-2200-0001. The phone connects to a downstream device
named PC B whose MAC address is 0022-2200-0002 and to Ethernet 1/0/2 on Device A.
•
Device A uses voice VLAN 2 to transmit voice packets for IP phone A and uses voice VLAN 3 to
transmit voice packets for IP phone B.
•
Configure Ethernet 1/0/1 and Ethernet 1/0/2 to operate in automatic voice VLAN assignment
mode. In addition, if one of them has not received any voice packet in 30 minutes, the port is
removed from the corresponding voice VLAN automatically.
