Dual stack IPv6 for IPv4 depletion

Thu Jul 16 00:48:39 UTC 2015

> On Jul 15, 2015, at 14:43 , Ricky Beam <jfbeam at gmail.com> wrote:
> 
> On Wed, 15 Jul 2015 17:23:52 -0400, Owen DeLong <owen at delong.com> wrote:
>> I will point out that nobody has said “what the F*** were they thinking” when they made it possible to use 4GB of RAM instead of just 640k, but lots of people have said “what the F*** were they thinking when they limited it to 640k.”
> 
> Actually, they did. And "PAE" was invented. (or "re-invented", as various paging mechanisms had existed for many decades by then)

Huh?

You’re missing the point or deliberately ignoring it, hard to tell which.

Vast address availability has never lead to WTF moments.
Restrictive addressing, OTOH, has created many WTF moments.

I look at NAT and I think WTF were they thinking, but it was an unfortunate consequence of the 32-bit limitation of IPv4.
It’s an effort at coping with the limitations, however misguided it may be.

I look at providers handing out /60 and I think WTF are they thinking. There’s no legitimate reasoning behind it.

Why repeat the same mistakes again by limiting IPv6 deployments to something less than /48?

As to your arguments on segmentation, no, RFC1918 is 3 segments because, again, of limitations in IPv4. In IPv6,
it’s still only one segment. Arguing that the 4th (which actually isn’t RFC-1918) is a segmentation isn’t entirely valid
as it’s more of an allocation than a segmentation and in any case, all of them are more than covered in the single
existing IPv6 segmentation of fc00::/0 or even fd00::/9.

Class E isn’t so much a segmentation as an early error that never got corrected. By the time anyone recognized the
need to fix class E, it was easier to move to IPv6 than to repair that part of IPv4, so we moved on.

255/8 is not really still applicable and does not apply to IPv6 in any way, so I don’t think you can count that one.
Same with 0/8. These weren’t segmentations, they were limitations of the technology at the time those RFCs
were written.

You can argue that localhost is a segmentation, I suppose, but in IPv6, it has reserved ::1/128.

Everything else in ::/3 is still available to the best of my knowledge.

So, in terms of total impact on IPv6, we’ve got three segmentations other than Unicast that are carried forward
from IPv4. No more, no less. (unless someone comes up with something not yet mentioned).

Owen