### VLAN Separation

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.

Table 8 provides several VLAN separation guidelines.

Table 8: VLAN Separation Rules
If |  | Then
--- | --- | ---
VLANSEP is “0” or "2" (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.
VLANSEP is “1” (On/Enabled) | AND the telephone is not tagging frames, OR if the telephone is tagging frames with a VLAN ID equal to PHY2VLAN, OR if the PHY2VLAN value is zero. | 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) | AND the telephone is tagging frames with a VLAN ID not equal to PHY2VLAN, AND the PHY2VLAN value is not zero. | Tagged frames received on the Ethernet line interface will only be forwarded to the secondary Ethernet interface if the VLAN ID equals PHY2VLAN. Tagged frames received on the Ethernet line interface will only be forwarded to the telephone if the VLAN ID equals the VLAN ID used by the telephone. Untagged frames will continue to be forwarded or not forwarded as determined by the Ethernet switch forwarding logic.