UDP broadcasting can only be used in a LAN environment
Even if no application on that host is actually interested in receiving the
packet each host on the LAN must:
receive packet
process the packet
Multicasting is the solution to both of these concerns
Appropriate for Internet use, as well as LAN use
Does not impose burdens on hosts that are not interested in receiving
the multicast data
Comparaison to real world news system
TCP/IP : equivalent to direct Mailing : Sender-controlled distribution
Broadcasting : equivalent to Radio
Multicasting : equivalent to newspaper distribution : Receiver-controlled
distribution where the local distributor are related to multicast capable
network routers