Re: Looking for an IPv6 naysayer...

[Owen DeLong <owen () delong com>]

On Feb 10, 2011, at 8:05 AM, Benson Schliesser wrote:

> On Feb 10, 2011, at 9:53 AM, Jack Bates wrote:
>
> > On 2/10/2011 8:36 AM, Benson Schliesser wrote:
> > > DS-lite is still CGN.
> >
> > It is still LSN, but it is not NAT444, and the failure rate reduces because of that. Also, DS-Lite guarantees that 
> > you have IPv6 connectivity. NAT444 makes no such assertion.
>
> DS-lite *uses* IPv6 connectivity, it doesn't provide it.  That's like saying 6rd or 6to4 "guarantees you have IPv4 
> connectivity".
>
> As for NAT444 (or double-NAT):  One could just as easily deploy DS-lite with a NAT444 configuration.  Or deploy CGN 
> without NAT444 (e.g. CGN44, by managing subnets delegated to each subscriber).  The two topics are related but 
> separate.
I think that at the point where you go to NAT444 instead of tunneling the IPv4, it's Dual-Stack, but, not 
Dual-Stack-Lite.

> In terms of CGN44 versus NAT444, I'd like to see evidence of something that breaks in NAT444 but not CGN44.  People 
> seem to have a gut expectation that this is the case, and I'm open to the possibility.  But testing aimed at 
> demonstrating that breakage hasn't been very scientific, as discussed in the URLs I posted with my previous message.
Technologies which depend on a rendezvous host that can know about both sides of both NATs in a private->public->private
scenario will break in a private->private2->public->private2->private scenario. There are technologies and applications 
which
depend on this. (I believe, among others, that's how many of the p2p systems work, no?)

Owen