2 When NICs use VLAN stripping on receive they must pass a pointer to a
3 \fBvlan_group\fR when reporting the stripped tag to the networking
4 core. If no \fBvlan_group\fR is in use then some drivers just drop
5 the extracted tag. Drivers are supposed to only enable stripping if a
6 \fBvlan_group\fR is registered but not all of them do that.
9 Some drivers size their receive buffers based on whether a
10 \fBvlan_group\fR is enabled, meaning that a maximum size packet with a
11 VLAN tag will not fit if no \fBvlan_group\fR is configured.
14 On transmit, some drivers expect that VLAN acceleration will be used
15 if it is available, which can only be done if a \fBvlan_group\fR is
16 configured. In these cases, the driver may fail to parse the packet
17 and correctly setup checksum offloading or TSO.