The relationship between the multicast group management protocol family and the multicast routing protocols family based on the network topology terms. Multicast is often employed in Internet Protocol (IP) applications of streaming media, such as IPTV and multipoint videoconferencing. In IP multicast the implementation of the multicast concept occurs at the IP routing level, where routers create optimal distribution paths for datagrams sent to a multicast destination address. Network-assisted multicast may also be implemented at the Internet layer using IP multicast.

Network assisted multicast may be implemented at the data link layer using one-to-many addressing and switching such as Ethernet multicast addressing, Asynchronous Transfer Mode (ATM), point-to-multipoint virtual circuits (P2MP) or InfiniBand multicast.

Copies are automatically created in other network elements, such as routers, switches and cellular network base stations, but only to network segments that currently contain members of the group. Group communication may either be application layer multicast or network-assisted multicast, where the latter makes it possible for the source to efficiently send to the group in a single transmission. Multicast should not be confused with physical layer point-to-multipoint communication.

Multicast can be one-to-many or many-to-many distribution. In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously.

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