Unicast vs Multicast vs Broadcast
Broadcast networks have a single communication channel that is shared by all the machine on the network.Broadcast systems allow the possibility of addressing a packet to all destinations by using a special code in the address field.
Sending a packet form one host to another in the same network or on a different network.
Multicast: One to Many
Multicast addressing is a network technology for the delivery of information to a group of destinations simultaneously.It uses each link only once for message delivery.It use the class D addressing system.It uses IGMP (Internet Group Management Protocol).
Broadcast: One to All
Example: Destination address 192.168.20.255 means sending a packet to all hosts of the network specified by the network id 192.168.20