Why don't they use IPv6 instead of uPnP?
They control the consumer box (and PS3, XBOX, .... are not cheap boxes) and they control the gaming servers.
Look at the feature back to my mac., it opens when possible an IPv6 over IPv4 toredo tunnel, so that apple servers can easily contact back the desktop. If not possible it falls back to NAT traversal with IPv4...
http://www.appleinsider.com/articles/08/08/19/apples_secret_back_to_my_mac_push_behind_ipv6.html
http://collison.ie/blog/2008/12/leopard-and-back-to-my-mac-tunnels
Once upon a time, Franck Martin <franck@genius.com> said:
Why don't they use IPv6 instead of uPnP?
UPnP (or something like it) is needed for any kind of firewall for some
devices.
At least on Xbox, some games are essentially peer-to-peer; when userA
starts it up and invites friends, their Xbox becomes the game server.
The other people joining the game talk directly to userA's Xbox (they
don't go through a Microsoft Xbox Live server).
When userA sets up the game, their Xbox sends a UPnP request to the
local firewall to open up a port so outside connections can come in. It
doesn't matter if there is IPv4, IPv6, NAT, etc. in play; the Xbox is
saying "let the Internet talk to me on port foo for a bit".
Now, the security model (or lack thereof) of UPnP can be debated, but
home users are going to need something like that for peer-to-peer
networking. IPv6 is supposed to bring back end-to-end networking and
abolish NAT, but I think most people agree that the average home user
will still need a basic statefull firewall for protection, which means
there has to be a protocol for some devices to temporarily open up ports
on the firewall (or there's still no end-to-end).