Rob Seastrom rs at
Fri Nov 29 13:39:59 UTC 2013

I'd like to call everyone's attention to ARIN's policy on IPv6
transition space which
was created specifically in response to the standardization of 6rd.

The discussion at the time that this policy was under consideration
was that encoding the [m,n] in a non-overlapping fashion when one has
a bajillion allocations due to slow start was a pain in the butt and
that, in practice, everyone would just encode 32 bits of IPv4 into 6rd.

Note that it's possible to get a /24 of IPv6 space (huge!).  Yes, it's
from space that is "tainted" as being marked as transition space.
Yes, you have to recertify that you're using it for the intended
purpose every three years.

Of course, 24 + 32 = 56.  This is not an accident.  It was our sense
at the time that /56 was bad enough and that there was no reason to
codify giving people an even more parsimonious slice of IPv6 space.

So there really is no excuse on AT&T's part for the /60s on uverse 6rd...


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