.IP \(buWhen NICs use VLAN stripping on receive they must pass a pointer to a\fBvlan_group\fR when reporting the stripped tag to the networkingcore. If no \fBvlan_group\fR is in use then some drivers just dropthe extracted tag. Drivers are supposed to only enable stripping if a\fBvlan_group\fR is registered but not all of them do that...IP \(bu
Some drivers size their receive buffers based on whether a\fBvlan_group\fR is enabled, meaning that a maximum size packet with aVLAN tag will not fit if no \fBvlan_group\fR is configured...IP \(buOn transmit, some drivers expect that VLAN acceleration will be usedif it is available, which can only be done if a \fBvlan_group\fR isconfigured. In these cases, the driver may fail to parse the packetand correctly setup checksum offloading or TSO.