IP address
An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
An IP address serves two principal functions: host or network interface identification and location addressing.
IP address
A multicast address is associated with a group of interested receivers. In IPv4, addresses through (the former Class D addresses) are designated as multicast addresses. IPv6 uses the address block with the prefix for multicast applications. In either case, the sender sends a single datagram from its unicast address to the multicast group address and the intermediary routers take care of making copies and sending them to all receivers that have joined the corresponding multicast group.