DatagramSocketImpl in Java has a
joinGroup method that takes a socket address (IP and PORT) plus the interface address (IP and PORT). I am trying to understand the difference and purpose of each of those three addresses in the multicast stack:
- What is the purpose of the bind address? Does it need a port?
- What is the purpose of the interface address? Does it need a port?
- What is the purpose of the multicast address? Does it need a port?
I am confused: I don't know the difference between the bind address and the interface address. Also, I am not sure if the multicast address really needs a port. Can I call the IP of the multicast address the multicast address group?