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
