At 9:30 PM +0200 9/30/07, Iljitsch van Beijnum wrote:
On 30-sep-2007, at 5:10, John Curran wrote:
The irony is that the I* rationale for moving NAT-PT to historic was "to restore the end-to-end transparency of the Internet" and yet the only real chance we have to restore end-to-end transparency is to first have a transition to the IPv6 (using dual-stack, NAT-PT, and every other tool at our disposal) and then over time let present IPv4 destination sites add IPv6 for end-to-end transparency based on their actual need for it. Instead, central planning may have effectively killed the very tool that's needed to allow providers to provision new Internet customers over a pure IPv6-only model, and create the right motivation for existing Internet sites to go dual-stack and actually gain "end to end transparency" via IPv6.
In my opinion, the mistake the IETF made was to "deprecate" NAT-PT without coming up with an alternative first.
Agreed. Lucklily, it got spec'd and it's now a question of what ISP's want and what vendors feel like making money.
Originally, my thinking was "sure, NAT-PT doesn't work with everything unless you have ALGs for a good number of protocols, but it gives you 80% of what you need so it's a good start". But I've come to see how having IPv6 applications expect end-to-end IPv6 connectivity and then have that rug pulled from under them will inevitably lead to the same lack of end-to-end transparency in IPv6 that we currently have with IPv4. And once that can is open, it's unlikely we can get the worms to crawl back inside later.
I disagree with that view... There's no reason why NAT-PT for access to legacy IPv4 sites implies anything about the connectivity model for IPv6. As noted above, it's *lack* of NAT-PT that will cause ISP's to avoid a connecting customers with a pure IPv6 model, since that isn't enough for full Internet connectivity in the absence of NAT-PT. /John