[arin-ppml] Draft Policy ARIN-2024-8: Restrict the Largest Initial IPv6 Allocation to /20

[Tyler O'Meara]

Hi Bill and David,

Those are the 2 reasons for nibble alignment that I was aware of. Personally, I
think once we get to a large enough allocation size those reasons aren't worth
the wasted address space, but as that's not the purpose of this policy so we
should probably agree to disagree on that point.

It's worth noting that the nibble boundary requirement doesn't apply to
subsequent allocations that result in expansions currently. 

Tyler

On Fri, 2024-06-28 at 10:35 -0700, William Herrin wrote:
> On Fri, Jun 28, 2024 at 9:27 AM Tyler O'Meara <arin at tyleromeara.com> wrote:
> > If I may, why do you believe nibble alignment is important?
> 
> Hi Tyler,
> 
> Nibble boundaries offer two valuable characteristics in IPv6:
> 
> First, it simplifies reverse DNS delegation since ip6.arpa is
> implemented on nibble boundaries.
> 
> Second, it makes it easier to understand written IPv6 addresses and
> subnets, since the subnet boundary always occurs between written
> digits instead of causing those digits to change.
> 
> I agree with David on the nibble boundary issue. I concede David's
> point that when arguing against a /16 I'm really arguing against a /19
> because anyone reasonably justifying a /19 should see their netmask to
> expand to /16 to meet the nibble boundary requirement. To be clear: I
> think /19 is more than should be allocated based solely on the
> intentionally weak technical justifications we've selected. And I'm in
> favor of keeping the intentionally weak technical justifications for
> smaller allocations.
> 
> Regards,
> Bill Herrin
> 
>