IPv6 multicast works by nodes joining multicast groups by sending Multicast Listener Discovery (MLD) report messages.

Multicast groups are not constrained by local or global (network) geography.

• Whether the host is on the local network or on the internet, as long as it is signaling to join a multicast group, it can receive multicast packets sent to that group.

Any host can be a sender, whether it is part of the multicast group or not.

• Only hosts part of the multicast group are receivers.
• Hosts can join or leave multicast groups dynamically at any time.

IPv6 multicast addresses: FF00::/8

Well-known IPv6 multicast addresses