IP Multicast (1)
routing technique that allows IP traffic to be sent from one or multiple sources to multiple destinations
a single packet is sent to a multicast group ( single IP destination group address)
IP multicasting is similar to IP broadcasting except that instead of all hosts receiving the data, only systems which belong to a multicast host group receive the data.
a multicast host group is a group of systems which have the same Class D IP destination address (for example 224.99.0.6); Class D covers addresses: 224.0.0.0 - 239.255.255.255