Owen DeLong wrote:
Showing that you don't actually understand what everyone else means when they say "end-to-end".
Where is your point only to demonstrate that you don't understand what"end to end" means?
No carrier is going to implement that for obvious reasons.
Besides, that's not transparent end-to-end, that's predictably opaque end-to-end.
With no reasoning of you, I can simply say: WRONG
UPnP provides information for clients to restore IP and TCP headers from local ones back to global ones, which is visible to applications.
But it doesn't work across multiple layers of NAT.
It is trivially easy to make UPnP works across multiple layers of UPnP capable NAT.
Now, redraw the diagram for the real world scenario:
host <-> UPnP NAT <-> Carrier NAT <-> Internet <-> Carrier NAT <-> UPnP NAT <-> host
Tell me again how the application signaling from UPnP survives through all that and comes up with correct answers?
It is trivially: host <-> home UPnP NAT <-> Carrier UPnP NAT <-> Internet <-> Carrier UPnP NAT <-> home UPnP NAT <-> host Masataka Ohta