Figure 1 is an animation showing a unicast transmission.  A PC with the IP address 172.16.4.1 needs to send a packet to a network printer at 172.16.4.253.  The packet is sent to a switch and then the packet is forwarded onl to the printer. Figure 2 is an animation showing a broadcast transmission.  A PC with the IP address 172.16.4.1 is sending a broadcast message to all the other devices.  The switch receives the frame and sends it out all other ports except for the port from which it received the frame. Figure 3 is an animation of a multicast transmission.  A PC with the IP address 172.16.4.1 is sending a multicast message to the multicast address of 224.10.10.5.  Two of the devices on the network are members of this multicast group and they each receive a copy of the frame.