Re: Tunnel-to-NAT scenario

[Jari Arkko <jari.arkko@piuha.net>]

Iljitsch,

> In my opinion, it's an open question whether tunneling is a better 
> approach than translation for this use case (IPv4 clients connecting 
> to IPv4 servers through an IPv6 network). Doing the work in softwires 
> de facto answers that question through process rather than consensus.
Softwires have been told that they shall employ tunneling to cross the 
v6-only cloud. The NAT that I mentioned comes only after this; its 
almost completely a separate component (except for the fact that you 
need to know which tunnel interface packets came on to deal with 
overlapping RFC1918 space at the customer sites).

I hope no one is no longer arguing that we should do a double NAT. I 
think that would be wrong because tunneling ensures that your IPv4 
traffic is as intact as possible. Yes, it may eventually get NATted, but 
I do not want to create technology that forces you to do it no matter 
what is at the other end. For instance, with a tunnel-based crossing of 
the v6-only cloud customers sites that have public IPv4 space will not 
see any NAT effects.

Jari