> Add to that a transition model that > _requires_ that every host be dual-stacked before the first > v6-only node appears and you've got a horrible > chicken-and-egg problem where nobody has any incentive to > create a critical mass of dual-stacked hosts. If that was true, you'd be right, but it's not, therefore you are wrong. >From an operator viewpoint, IPv6 can be deployed without dual-stack either by using 6PE on an MPLS core, or by building an IPv6 overlay core using tunnels. Neither requires dual-stack everywhere, in fact both models of deployment are desirable specifically because they focus the change on just one part of the network. > NAT-PT was a reasonable solution to this (with a few tweaks), > since it could make hosts _appear_ to be dual-stacked with > little effort, but it offended the purists and was killed > despite there being nothing to replace it. What's this about NAT-PT being killed? I still see vendor literature which mentions NAT-PT support. If it works, and it is implemented, then people will use it. Same thing goes for Application Layer Gateways, i.e. proxies. I don't think any network operator is in the business of being an IETF purist. It is desirable that hardware and software adheres to standards but it is more important for them to *WORK*!!! And if there is a standards vacuum, that will not stop deployment. --Michael Dillon _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf