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Hi James,<br>
<br>
Thanks for your note and that of others on this topic.<br>
<br>
As merely a member of the IETF community, I'm representing a broader
set of views than my own, and I may be doing a poor job of it.
Please ask others if you like on the int-area mailing list that can
be found via <a class="moz-txt-link-abbreviated" href="http://www.ietf.org">www.ietf.org</a>.<br>
<br>
On 6/27/10 8:58 PM, James Hess wrote:
<blockquote
cite="mid:AANLkTilFYpJOe2RsfP_DZfqassh-QgtDOm0DijUJAAB9@mail.gmail.com"
type="cite">
<pre wrap="">On Sun, Jun 27, 2010 at 6:10 AM, Eliot Lear <a class="moz-txt-link-rfc2396E" href="mailto:lear@cisco.com"><lear@cisco.com></a> wrote:
[snip]
</pre>
<blockquote type="cite">
<pre wrap="">It would take forever to fix printers, fridges, and other appliances, along
with routers, firewalls, and other middle boxes.
</pre>
</blockquote>
<pre wrap="">If IP enabled fridges can no longer use the LAN, then so be it..
It may be hard to convince manufacturers of even new devices to 'fix'
it, yes, but
forever is a long time. And the time it takes is measured starting
_from the time the block is no longer marked as special_. Currently
deployed printers, fridges, and other appliances have not even been in
service using IPv4 forever.
</pre>
</blockquote>
<br>
I would suggest you consider a <a
href="http://en.wikipedia.org/wiki/Diffusion_of_innovations">Rogers
Innovation Adoption Curve</a>, and consider that for IPv6 alone,
estimates for adoption are very very long periods of time (many
decades) [<a href="#Elmore08">Elmore08</a>][*], and IPv6 is
considered a substantial improvement to the situation such that,
absent a paradigm shift, we will not see need for larger addresses.
Now consider something with considerably less draw, like 16 (really
15) /8 blocks, and the incentive to actually code changes for IPv4
would be limited at best. Taking this into account, as well as when
we think the first use would be safe for those who would need it,
one could conclude "forever" may very well be accurate in this
case. One way we can test this is that I can tell you that to the
best of my knowledge (and I was one of the authors proposing using
240/4) we received very little interest from customers who might
benefit from this space being used, even after we put an idea
forward. That's a pretty good indicator that we were on the wrong
path. <br>
<br>
There may yet be a right path for 240/4 that we haven't considered.
Some of your ideas, James, about specific applicable uses of that
space may yet hold water, but would have to be compared against the
costs and benefits of going to v6 at the microeconomics level,
because it seems likely that v6 would be substitutable for many such
cases. The reverse is assuredly not so.<br>
<br>
All of this having been said, we have what amounts to an image
problem with that space, at least for now. The above analysis is a
cursory summary, and even so is not easily digested. This leaves
the community open to attacks by those who haven't seriously
considered the problem and may wish to make hay of it. My only
answer to that is that such open public discussions as the one we
are engaged in are very VERY useful to assure there's not an angle
we have missed.<br>
<br>
Eliot<br>
<br>
[<a name="Elmore08"></a>Elmore08] Diffusion and Adoption of IPv6
in the ARIN Region, Elmore, H., Camp., LJ, Stephens, S, Workshop on
the Economics of Information Security, June 2008.<br>
[*] The above paper was an early estimate with limited information.
I would welcome additional work along the same lines with updated
information.<br>
<br>
Eliot<br>
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