My experience with IPv6 is quite limited, so if anyone would care to explain how it works, feel free. I am quite familiar with regular old ipv4, but that is about it.
Well, just the basics: It basically avoids the problem of a limited adress range. There are way more devices in the world than there are possible adresses in IPv4. To solve that, ports are used to send a response to a specific client. Your internet router must have something to decide if the incoming data is supposed to go to your smartphone or your PC.
IPv6 offers a much wider adress range and allows direct communication without additional ports (your computer and your smartphone both connected to your router will have different IPv6 adresses - if supported).
Galaxy does not require IPv6.
Edit: Of course I forgot to mention subnets, but I guess these are self-explanatory.
And to those who know more about the matter than me: I hope I didn't say too much wrong, feel free to correct me.