When enabled along with MLD, any IPv6 Multicast
packets that are not joined by an MLD host will
will be restricted to ports that have detected a
multicast router or ports that are configured to
always forward IPv6 multicast. When set to disabled
or when MLD is disabled, the unjoined IPv6 multicast
packets will be flooded out all ports in the VLAN.
Permanently assigned multicast addresses are always
flooded and so are not impacted by this object.