Multicasting

Watch this video from 59:10 to 1:06:39 to learn about multicast networking and how it enables data to be sent to multiple specified recipients by using special IP addresses representing a group of hosts. This type of selective broadcasting is helpful for applications such as streaming media, where it is efficient for one source to transmit to many receivers, such as a live lecture being sent to online students. Why is multicast more efficient than unicast or broadcast in this scenario? What mechanisms allow a host to join or leave a multicast group, and how does the network keep track of the memberships? What is multicast's role in optimizing network traffic and managing bandwidth, particularly when the same data is sent to many users?