<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Oct 14, 2010, at 2:36 PM, Mark Townsley wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
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On 10/14/10 11:06 PM, Owen DeLong wrote:
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<div>On Oct 14, 2010, at 1:51 PM, Lorenzo Colitti wrote:</div>
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<div class="gmail_quote">On Thu, Oct 14, 2010 at 8:02 AM, Owen
DeLong <span dir="ltr"><<a moz-do-not-send="true" href="mailto:owen@delong.com">owen@delong.com</a>></span>
wrote:<br>
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<div>If you can get 6rd to fit in single /16, then,
perhaps we could consider allowing it to be permanent.</div>
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<div>However, if ~3,000 ARIN members deploy 6rd /24s,
then, you're talking about the vast majority of an
entire /12 just in the ARIN region.</div>
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<div>Why not we make it a /28, and thus give the customer a
/60? The customer still gets 16 subnets for his house, and
when 6rd goes away (since, as you point out there are
other disadvantages beyond address space use compared to
native IPv6), then the subnet will be /56 (since,
following your reasoning, that is what competitors with
native IPv6 access will be providing).</div>
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/60s are horrible... They completely stifle any ability for the
customer to do PD-based topology</div>
<div>within the site.</div>
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I think you are assuming what the PD-based topology mechanisms are
going to be. They haven't really been designed, and certainly
haven't been coded and shipped yet. All we are doing at this point
is providing a playing field. Within that field:<br>
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/60 is an *enormous* improvement over /64. Night and day.<br>
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/56 is certainly better than /60, but not night and day as with /64
and /60. <br>
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The point here is that if we design home routing and PD for 2^4
subnets, it's not hard to take that and extend it for 2^8 or 2^16.
Not so if you are starting with 2^1.<br>
<br></div></blockquote>With all due respect, I must strongly disagree here. Whatever we decide here will likely impact and set the standards by which home gateways are designed going forward.</div><div><br></div><div>We agree that /64 is a non-starter.</div><div><br></div><div>I strongly believe that the target should be /48. That 6rd has such terrible deficiencies in its use of address space that we cannot afford /48 and therefore must compromise to /56.</div><div><br></div><div>Further compromising to /60 runs the risk of that becoming a de facto industry standard which will potentially be very difficult to overcome.</div><div><br></div><div>You asked me to tell you if you are contradicting someone from your organization... You are contradicting Tony</div><div>Hain here, or, at least my understanding of what Tony has been saying.</div><div><br><blockquote type="cite"><div bgcolor="#ffffff" text="#000000">
Consumer products will be designed to operate within the lowest
common denominator of the above. If we can make that /60 vs. /64,
that's a big win and we might see some potential for upsell into /56
for "bigger home networks". But, if we have to do a ton of work to
make networks work within a single /64 anyway, once we have done
that, it's hard to argue for supporting multiple subnets as well.
I'm trying to avoid having to do the work at all for /64, but that
can only happen if I know the minimum number of subnets in the home
is greater than 1. <br>
<br></div></blockquote>That is, indeed, the source of my concern. If consumer products are developed only to the lowest common denominator,</div><div>we risk establishing /60 as that point. /56 is bad enough. As I have said, we should strongly encourage /48 as the</div><div>standard around which development occurs while recognizing /56 as a necessary limitation of 6rd.</div><div><br></div><div>I don't think we are disagreeing here, and I don't think anyone is advocating /64s. The AC has approved and forwarded</div><div>to last call policy which enables /56s for 6rd, but, encourages treating those as temporary and transitional in nature.</div><div>I think this is the best compromise.</div><div><br></div><div>Owen</div><div><br><blockquote type="cite"><div bgcolor="#ffffff" text="#000000">
- Mark<br>
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<div>I would point out that the only ISP I am aware of that
is conducting residential trials of IPv6 seems to be
talking about giving only a /64 to the home by default due
to CPE issues. To me, that is a much greater problem than
having a /60 instead of a /56, because with a /64 you
can't do any subnetting at all.</div>
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<div>True... /64 should be even more discouraged than /60, but,
the reality is that we should look at</div>
<div>/56 as a temporary expedient due to inefficiencies in 6rd and
consider /48 the norm.</div>
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<div>Owen</div>
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