Multicast

Multicast is a technique for distributing a packet to multiple receivers in a network by sending only one packet. Instead of a sender determining who will receive a packet, network hardware (such as routers or switched hubs) duplicates a packet and sends it to everyone participating in a chosen group. A target does not actively participate by sending a join request. The network hardware involved periodically broadcasts membership queries throughout a network, and these have to be answered with a membership report in the event that a target wants to participate in the queried group.