On December 13, 2014 6:27 PM, Ted Lemon wrote > On Dec 13, 2014, at 3:09 PM, Christian Huitema <huitema@xxxxxxxxxxxxx> wrote: >> But the applications have no official way to learn the range. > > Isn't that what PCP is for? You don't need to know the range: you just need a port (or range of ports) allocated. PCP MAP would work, if well implemented. But many home routers do not support PCP yet, and many applications work better on their "preferred" port. Of course, all that can be fixed with sufficient effort, but it might be simpler for the applications to just go to IPv6. Also, 6346 mentions deployment directly to devices like cell phones, and there is no PCP there. I understand that a big motivation of A+P is to avoid Carrier Grade NAT, and I sympathize with that. But I can see some interesting trouble ahead... -- Christian Huitema