On Dec 13, 2014, at 10:36 PM, Christian Huitema
<huitema(_at_)microsoft(_dot_)com> wrote:
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...
Hm, I see your point, and I agree that it will be easier for apps to go to
IPv6, at least in principal (availability of IPv6 is still a problem in many
situations). However, even if apps go to IPv6, there is significant utility
in using PCP, particularly in situations where the HG may have a firewall with
a default block policy for incoming connections. So I don't really think
there's any reason to separate the two things. Really, apps should support
IPv6, and they should support PCP. And home gateways should support it as
well; it's frustrating that at present there is no good PCP implementation for
OpenWRT, for example.
The mobile/PCP intersection is interesting--I haven't seen any exploration of
that yet.