In IPv6, what term refers to communication that reaches multiple specific nodes?

In IPv6, the term that refers to communication that reaches multiple specific nodes is multicast. Multicast allows a sender to communicate with a group of interested receivers simultaneously rather than sending separate copies of the data to each receiver. This is efficient for scenarios where data needs to be delivered to multiple destinations, such as streaming video or audio to a group of users.

The multicast addresses in IPv6 start with the prefix FF00::/8, and they provide a mechanism where a single data stream can be distributed to multiple nodes that have expressed interest in receiving that stream. This characteristic is essential in many applications, including online gaming, video conferencing, and other group communication services.

Unicast, on the other hand, refers to one-to-one communication, where a packet is sent from a single sender to a single receiver. Anycast addresses allow data to be sent to any one of a group of nodes, typically the closest one, but this does not imply multiple specific nodes are involved. Broadcast is not supported in IPv6 as it was in IPv4; instead, multicast is used for similar functions.