Re: [v6ops] discussion of transition technologies

Lee Howard <> Mon, 22 January 2018 21:17 UTC

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Date: Mon, 22 Jan 2018 16:17:26 -0500
From: Lee Howard <>
To: Fred Baker <>, Ole Troan <>
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Thread-Topic: [v6ops] discussion of transition technologies
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Subject: Re: [v6ops] discussion of transition technologies
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On 1/22/18, 3:23 PM, "v6ops on behalf of Fred Baker"
< on behalf of> wrote:

>On Jan 22, 2018, at 11:17 AM, Ole Troan <> wrote:
>> What's the purpose of what you are trying to do?
>This started out as a question among the chairs, triggered in part by an
>academic article that I can't share because it's not public yet. It lists
>26 different transition mechanisms and tries to make recommendations,
>based in large part of recommendations we have made. The question started
>out as "can we narrow that to one such mechanism? Which ones are actually
>in use?" Now see the spreadsheet Lee shared, which comes from different
>It sounds like Ole's data on 6rd needs to get reflected in Lee's

I think it is; it lists five ISPs using 6rd, though I’ve heard rumors two
of them have switched to native dual-stack.
To me, that is exactly consistent with both Ole’s point (millions of
people use 6rd; it’s what you do what your edge network can’t handle IPv6
but you want to provide it) and my point (not seeing new deployments, old
deployments are dwindling).

>After quite a bit of discussion, we think we had pretty much re-invented
>RFC 6180. The discussion isn't over, but I suspect we're close. So Lee
>asked for opinions from you guys.
>And BTW, I suspect that dslite is a little long in the tooth for the same
>reason. The theory with both 6rd and dslite was/is that once there is a
>native path from here to there, even if the dslite configuration is still
>in the network it's unlikely to be used. That might be naive :-)

Responding to both paragraphs:
RFC6180 recommends DS-Lite in 4.3: The recommended tool for this model is
Dual Stack Lite [DS-lite
I’m not sure that would still be our recommendation, and it sounds like
you’re not, either.

It has the advantage of broad residential gateway support, and the
disadvantage of being stateful. The first advantage may decline over time,
but hasn’t yet.

>The big question among the chairs is "what is the real case for
>translation?" We see it in a variety of places, basically creating a way
>for IPv6-only devices or networks to talk with IPv4-only devices or
>networks, but wondering if there is a better way to proceed. My personal
>take is "it is what it is, no worse than IPv4/IPv4 translation" - not
>arguing for it, but considering it a fact of life until people become
>motivated to replace it with native systems and connectivity. YMMV.

Well, we kind of skipped the data center use cases, I think.
1. My data center is all IPv4, but I want IPv6-enabled hosts to reach it
(reasons of performance, logging, cost, etc.).
2. My data center is all IPv6, but I want IPv4-only hosts to reach it
(because 78% of the Internet is still IPv4-only).