[arin-ppml] v4 to v6 obstacles

[Lee Howard]

> > IPv6 is cheaper (for the ISP, who doesn't have to pass the expense on to you) 

> than large-scale NAT.
> >  
> But since they need to provide it *anyway* in order to give me dual-stack (which 

Large-scale NAT is only required after runout, and only for connections over IPv4.
More IPv6 traffic means few NAT boxes.

> > > On those days when, for whatever reason, the IPv6 
> > > is down... I don't even notice until I happen to see it in the logs.
> > That's the goal!  If you can't tell the difference, then that's a success!
> Actually that's the *problem*. If I can't tell the difference, then there's no 
> reason for me to demand IPv6 *or* for my provider to give it to me.

Maybe we have different goals.  My goal is to provide connectivity to my
customers.  IPv6 is a tool to do that, not an end in itself.

> 
> IF it is possible to continue indefinitely providing dual-stack (NAT or 
> otherwise for the IPv4), THEN it is possible to continue indefinitely *not* 
> providing IPv6 at all.
> 
> Until there's an application for which I *can* tell the difference, in a big 
> way.

Does anything break when it goes through two layers of NAT (i.e., 
home gateway NAT and CGN, a.k.a. NAT444)?  Several of the 
widely used NAT traversal systems assume a single NAT layer; not
sure how VoIP, online gaming, p2p will work with NAT444 (or, if
the other endpoint is also NAT444, you have NAT44444).  

Lee