CSC/FUNET There are many issues concerning the deployment and implementation, and to a lesser degree, specification of IPv6 multicast. This memo describes known problems, trying to raise awareness. Currently, global IPv6 interdomain multicast is completely impossible except using SSM: there is no way to convey information about multicast sources between PIM RPs. Site-scoped multicast is also problematic when used alongside to global multicast because of that. A few possible solutions are outlined or referred to. In addition, an issue regarding link-local multicast-blocking Ethernet switches is brought up. Finally, a feature request for MLD snooping switches is noted.