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Exceptions to the VLAN forwarding rules
Exceptions to the VLAN forwarding rules are as follows:
• LLDP frames are always exchanged between the following in all VLAN separation modes:
- The LAN port and CPU port
- The CPU port and LAN port
• Spanning tree frames are always exchanged between the LAN port and PC port in all VLAN
separation modes.
• 802.1x frames are always exchanged between the following in all VLAN separation modes
according to DOT1XSTAT and DOT1X configuration:
- The LAN and CPU port or PC port
- The PC and CPU port or LAN port
- The CPU port and LAN port
Special considerations
Special use of VLAN ID=0
The phone adds a VLAN tag to the egress voice frames with a VLAN ID=0 in certain
configurations. For example, to utilize the priority functionality of the VLAN frame only and not the
VLAN ID properties. In this case, use the parameter L2QAUD or L2QSIG to set the value of the
VLAN priority portion of the VLAN tag.
Automatic failback of VLAN tagging
The phone connects to a network when the value of L2QVLAN does not match with the VLAN
being assigned to the network access switch. When the phone starts to connect, it tries to contact
the DHCP server with a VLAN ID=L2QVLAN. If the phone does not receive a DHCPOFFER with
that particular VLAN ID, then it eventually fails back. The phone tries to contact the DHCP server
again if L2Q is set to 0 and the VLAN tag is not set.
The VLANTEST parameter determines how long the phone waits for a recognizable
DHCPOFFER. If VLANTEST is set to 0, then the phone does not fail back and keeps sending
DHCP requests by using tagged VLAN frames with VLAN ID = L2QVLAN.
VLAN support on the computer or PC port
In full VLAN separation mode, the phone only supports one VLAN on the computer port. In no
VLAN separation mode, all VLANs pass between the LAN and PC ports. However, the CPU port
receives all traffic even if on VLANs that are not equal to L2QVLAN.
VLAN parameters
The following tables lists the parameters which are used to configure VLAN functionality on the
network switch internal to the phone:
Servers, VLAN, and IP configuration
April 2020
Installing and Administering Avaya J100 series IP Phones in an Open SIP
environment
68