A table with VLAN sets. An interface belongs to the VLANs
described by the union of all VLAN ids specified in all VLAN
sets for the interface. Is possible to describe the same
VLAN ids either by using one or by using multiple VLAN
sets. Because the administrative data customer id and purpose
can be set per VLAN set, it is possible to assign these
differently for different VLAN ids when using multiple VLAN
sets.