IGMP Version 3

Hello Rene,
A few questions and confusions.

  1. When a multicast address is being used as a group address(for example 239.1.1.1), this address is assigned to the multicast server and this address has to have route in the network design because whenever a host will encapsulate an IP packet, it will use its own address as the source and 239.1.1.1 address as the destination address. Is this correct?
  2. Would you also please give me a real life scenarion where multicast is used?
  3. In your IGMP version 3 example, 1.1.1.1 is being used as the source address. What is this address for? As far as my understanding goes, source IP address is the host IP and destination is the Multicast IP address(239.1.1.1). Please explain it little bit.
  4. One difference between ver 2 and ver 1 is that in ver 1 all the hosts send report to the router whereas in ver 2 only host sends report to the router on behalf of all the hosts in the same group. Is it correct?

Thank you so much

Azm