VLAN Considerations
Issue 5 April 2010 75
VLAN separation controls whether or not traffic received on the secondary Ethernet interface
can be forwarded on the voice VLAN. VLAN separation also controls whether network traffic
received on the data VLAN can be forwarded to the telephone. The following system
parameters control VLAN separation:
●VLANSEP - enables (1) or disables (0) VLAN separation. The default is 1 (on), which
allows full separation. When set to 0 (off), VLAN IDs are not used as a criteria for
forwarding frames.
●L2Q - 802.1Q tagging must be set to 1 (on) or 0 (auto).
●L2QVLAN - must be set to the non-zero VLAN ID of the voice VLAN.
●PHY2VLAN - must be set to the non-zero VLAN ID of the data VLAN, which cannot be the
same as the voice VLAN ID.
●PHY2PRIO - the layer 2 priority value to be used for tagged frames received on the
secondary Ethernet interface.
Table9 provides several VLAN separation guidelines.
Table9: VLAN Separation Rules
If Then
VLANSEP is “0”
(Off/Disabled),
OR the telephone is
not tagging frames,
OR the telephone is
tagging frames with a
VLAN ID equal to
PHY2VLAN.
Frames received on the secondary Ethernet
interface will not be changed before
forwarding. For example, tagging is not added
or removed and the VLAN ID and tagged
frames priority are not changed. The Ethernet
switch forwarding logic determines that frames
received on the Ethernet line interface are
forwarded to the secondary Ethernet interface
or to the telephone without regard to specific
VLAN IDs or the existence of tags.
VLANSEP is “1” (On/Enabled) All tagged frames received on the secondary
Ethernet interface are changed before
forwarding to make the VLAN ID equal to the
PHY2VLAN value and the priority value equal
to the PHY2PRIO value.
Untagged frames received on the secondary
Ethernet interface are not changed before
forwarding.
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