Vlan Detection - Avaya 4600 Series Administrator's Manual

If VLAN tagging is enabled (L2Q= 0 or 1), the 4600 Series IP Telephones set the VLAN ID to
L2QVLAN, and VLAN priority for packets from the telephone to L2QAUD for audio packets and
L2QSIG for signalling packets. The default value (6) for these parameters is the recommended
value for voice traffic in IEEE 802.1D.
Regardless of the tagging setting, a 4600 Series IP Telephone will always transmit packets from
the telephone at absolute priority over packets from secondary Ethernet. The priority settings
are useful only if the downstream equipment is administered to give the voice VLAN priority.

VLAN Detection

The Avaya IP Telephones support automatic detection of the condition where the L2QVLAN
setting is incorrect. When VLAN tagging is enabled (L2Q= 0 or 1) initially the 4600 Series IP
Telephone transmits DHCP messages with IEEE 802.1Q tagging and the VLAN set to
L2QVLAN. The telephones will continue to do this for VLANTEST seconds.
If the VLANTEST timer expires and L2Q=1, the telephone sets L2QVLAN=0 and transmits
●
DHCP messages with the default VLAN (0).
If the VLANTEST timer expires and L2Q=0, the telephone sets L2QVLAN=0 and transmits
●
DHCP messages without tagging.
If VLANTEST is 0, the timer will never expire.
●
Note:
Regardless of the setting of L2Q, VLANTEST, or L2QVLAN, you must have
Note:
DHCP administered so that the telephone will get a response to a
DHCPDISCOVER when it makes that request on the default (0) VLAN.
After VLANTEST expires, if an Avaya IP Telephone running R2.6 receives a
non-zero L2QVLAN value, the telephone will release the IP Address and send
DHCPDISCOVER on that VLAN. Any other release will require a manual reset
before the telephone will attempt to use a VLAN on which VLANTEST has
expired. See the Reset procedure in Chapter 3 of the 4600 Series IP Telephone
Installation Guide.
The telephone ignores any VLAN ID administered on the media server if a
non-zero VLAN ID is administered either:
- by LLDP
- manually,
- through DHCP, and/or
- through TFTP or HTTP.
VLAN Considerations
Issue 5 November 2006 87