At 12:56 PM -0500 10/1/07, Stephen Sprunk wrote:
... The fundamental flaw in the transition plan is that it assumes every host will dual-stack before the first v6-only node appears. At this point, I think we can all agree it's obvious that isn't going to happen.
NAT-PT gives hosts the _appearance_ of being dual-stacked at very little up-front cost. It allows v6-only hosts to appear even if there still remain hosts that are v4-only, as long as one end or the other has a NAT-PT box. The chicken and egg problem is _solved_. When v4-only users get sick of going through a NAT-PT because it breaks a few things, that will be their motivation to get real IPv6 connectivity and turn the NAT-PT box off -- or switch it around so they can be a v6-only site internally.
The alternative is that everyone just deploys multi-layered v4 NAT boxes and v6 dies with a whimper. Tell me, which is the lesser of the two evils?
Stephen - Very well said... Now the more interesting question is: Given that we're going to see NAT-PT in a lot of service provider architectures to make deploying IPv6 viable, should it be considered a general enough transition mechanism to be Proposed Standard or just be a very widely deployed Historic protocol? Oh wait, wrong mailing list... ;-) /John