Subject: RE: ITU-T Dubai Meeting and IPv15

From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Thu, 9 Aug 2012 12:45:05 -0400

> From: Phillip Hallam-Baker [[email-masked]]
> 
> As Tom Knight pointed out when the IPv4 address size was chosen, there
> aren't enough for one for each person living on the planet.
> 
> Remember that we are trying to build a network that is going to last
> for hundreds if not thousands of years.

Technology changes over time, and so the optimal design tradeoffs
change over time.  When IPv4 was designed, memory, processing power,
and transmission capacity were far more expensive than now.  Moore's
Law suggests a factor of 2^15 between 1982 and 2012.  Before that was
the ARPAnet, with 8 bit addresses, which lasted for around 15 years.
Presumably IPv6 will suffice for at least another 30 years.

The real issue regarding longevity is that total network overhauls
should be infrequent enough that their amortized costs are well less
than ongoing operational costs.  Once that has been achieved, the cost
savings of designing a protocol with a longer usable lifetime is
probably not worth the effort of trying to predict the future well
enough to achieve longer lifetime.

Extrapolating a 30-year lifetime for each IP version suggests that in
300 years we will reach the end of the usable life of IPv15 and will have
to allocate more bits to the "version" field at the beginning of
packets.  That'll be a mess...

Dale

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From: "Andrew G. Malis" <[email-masked]>
Date: Fri, 10 Aug 2012 13:22:51 -0400

A 260-bit address should be sufficient to address every atom in the
universe, according to current estimates (10^78 atoms). We go there
next (plus some extra to add hierarchy), and we'll never have to worry
about addressing again.

Another alternative is self-describing variable-length addresses,
again do it once and we'll never have to worry about it again.

Cheers,
Andy

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From: David Conrad <[email-masked]>
Date: Fri, 10 Aug 2012 10:35:53 -0700

> again do it once and we'll never have to worry about it again.

Heretic!  That's OSI speak!  Why do you hate the Internet you ISO/ITU lackey?!?

</flashback>

Yeah, variable-length addresses would have been nice. There was even working code. Maybe next IPng.

Regards,
-drc

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From: Donald Eastlake <[email-masked]>
Date: Sat, 11 Aug 2012 13:13:01 -0400

One problem with excessively large fields, including variable length
addresses with a high maximum length, is that the next time someone
wants to encode some additional information, they just tuck it inside
that field in some quasi-proprietary way, instead of going to the
trouble of actually adding a field. Witness X.509 Certificate "serial
numbers", which are arbitrary precision integers, but which frequently
are used for a variety of information, all BER encoded...

Thanks,
Donald
=============================
 Donald E. Eastlake 3rd   +1-508-333-2270 (cell)
 155 Beaver Street, Milford, MA 01757 USA
 [email-masked]

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From: joel jaeggli <[email-masked]>
Date: Sat, 11 Aug 2012 10:46:27 -0700

> are used for a variety of information, all BER encoded...
given various semantic uses of bits within ipv6 addresses that have been 
proposed or which are used informally even with only 128 bits it's 
important to make this distinction. a freely extensible bit field will 
end up with all sorts of garbage in it, that at best is only signficant 
in one context, and at worse is significant in different fashions in 
different contexts.

instead of having an locator-id you have a 
locator-qos-mpls-subscriberid-streetaddress-latlong-id