3Com corebuilder 3500 Implementation Manual page 197

Table 23 Ingress Rules for IEEE 802.1Q Tagged Frames Based on VLAN Mode and Software Release Number
VLAN Mode Release 1.2
allOpen The tagged frame is
assigned to one of the
configured VLANs if:
The VID of the frame
matches that of a
VLAN
and
A port in that VLAN
is tagged
allClosed The tagged frame is
assigned to one of the
configured VLANs if:
The receive port is in
a VLAN with a VID
that matches that of
the frame
and
A port in that VLAN
is tagged
The ingress rules for tagged frames vary for the various system releases.
Table 23 summarizes the differences.
Release 2.0
The tagged frame is
assigned to one of the
configured VLANs if:
The VID of the frame
matches that of a
VLAN
The tagged frame is
assigned to one of the
configured VLANs if:
The receive port is in
a VLAN with a VID
that matches that of
the frame
Rules of VLAN Operation
Release 3.0
The tagged frame is
assigned to one of the
configured VLANs if:
The VID of the frame
matches that of a
VLAN
and
The protocol type of
the frame matches
that of the same
VLAN
The tagged frame is
assigned to one of the
configured VLANs if:
The receive port is in
a VLAN with a VID
matching that of the
frame
and
The protocol type of
the frame matches
that of the same
VLAN
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Action Without
Required Match
The frame is
assigned to the null
VLAN. It can still be
forwarded
(untagged) if the
destination address
of the frame is
associated with
another port in the
bridge address table.
The frame is
assigned to the null
VLAN and dropped.