When multiple receivers are required to get the same data at approximately the same time, multicast is a more efficient way of delivering data than unicast.

A unicast packet has a single source IP address and a single destination IP address. Data will be delivered to a single host. A multicast packet has a single source IP, but it has a multicast destination IP address that will be delivered to a group of receivers. The advantage is that multiple hosts can receive the same multicast stream (instead of individual streams), thereby saving bandwidth.