What does the term "multicast" refer to in networking?

The term "multicast" in networking specifically refers to the method of transmitting data to multiple hosts simultaneously using a single multicast address. This approach is efficient because it allows the sender to send one copy of the data stream to the multicast group address. Hosts that wish to receive the data can join the multicast group, and they will receive the data without the sender needing to create multiple individual streams for each recipient.

Multicasting is particularly useful for applications such as video conferencing or streaming media, where the same data needs to be sent to multiple users at once, conserving bandwidth compared to sending separate streams to each recipient.

This is contrasted with unicast transmission, which involves sending data to a single host, and broadcast transmission, which sends data to all devices on a network. Multicast operates within a specific scope defined by the multicast address, ensuring that only those devices that are part of the multicast group receive the data.