Subject: [BEHAVE] comments draft-denis-behave-v4v6exthdr

From: james woodyatt <[email-masked]>
Date: Wed, 25 Mar 2009 11:27:21 -0700

everyone--

I had a brain-fade and didn't register with me that, yes, in fact, I  
had read the draft before the presentation.  I have two comments:

p1. As Dave Thaler argued, there may be multiple legacy NAT44s in the  
path from any particular IPv4 source to an IPv6 destination, and the  
utility of the information inserted by a NAT64 with this extension  
header for making address referrals to other IPv4-translated peers of  
an IPv6 node is therefore basically epsilon.

p2. I think it may be premature to take up this work for another  
reason.  Until the 6AI controversy is concluded, I think we cannot yet  
say with certainty that we only have to worry about NAT64  
translators.  We may also have NAT66 translators to consider.

I'm not a supporter of this draft.

--
james woodyatt <[email-masked]>
member of technical staff, communications engineering

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From: "Rémi Denis-Courmont" <[email-masked]>
Date: Thu, 26 Mar 2009 01:56:09 +0200

> an IPv6 node is therefore basically epsilon.

Hmm. I for one do not think that putting a NAT64 behind a legacy NAT is such a 
great idea. Of course, it will sometime happen. I just wonder how frequent 
that will be. At least, that's an easy to detect failure mode (this is 
documented already). Additionnaly, the option does let the application know 
that the flow is being protocol-translated, independent of NAT44.

> translators.  We may also have NAT66 translators to consider.

You have a point. That being said, it would be fairly trivial to extend it to 
support NAT66, if it is specified, and would make a lot of sense. In fact, in 
that case, the nested legacy NAT problem is non-existent. I admit I did not 
imagine the IETF would consider NAT66 when I initially wrote the original 
document.

However, I am unclear whether you're against the document ever, or against the 
document now... ?

-- 
Rémi Denis-Courmont
Nokia Devices R&D, Maemo Software, Helsinki

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From: james woodyatt <[email-masked]>
Date: Wed, 25 Mar 2009 17:25:01 -0700

On Mar 25, 2009, at 16:56, Rémi Denis-Courmont wrote:
>
> However, I am unclear whether you're against the document ever, or  
> against the document now... ?

I'd like to see the 6AI controversy resolved before considering this  
proposal.  If 6AI results in NAT66 becoming a permanent fixture of the  
Internet, then I'd like to see a substantially different version of  
this proposal aimed at helping with address referrals in the presence  
of both NAT66 and NAT64.  On the other hand, if 6AI fails to make  
NAT66 into a permanent fixture of the Internet, then whatever shim-and- 
tunnel solution we need to come up with to satisfy the open problems  
that 6AI is facing may in fact be adaptable as a coex64 mechanism if  
we play our cards right.

Summary: I'm against the document now.  I might change my mind later  
as the situation evolves, though I suspect that if I *do* ever come  
around, it will be too late to do so.