[arin-ppml] Draft Policy 2011-5: Shared Transition Space for IPv4 Address Extension - IAB comment

[William Herrin]

On Wed, Jun 29, 2011 at 5:21 AM, Owen DeLong <owen at delong.com> wrote:
> On Jun 28, 2011, at 10:35 PM, Joel Jaeggli wrote:
>> no it isn't. there is a tangible difference between a
>>scenario where something will not be configured and
>>therefore will never fail and a, something which fires
>>packets into the ether becuase it doesn't know any
>>better. LSN is here, allocating a new prefix or squatting
>>on public scope prefixes will break some fraction of old
>>cpe (it does today) in worse way then allocating them
>>out of private scope prefixes (for which they already
>>have logic) until they age out of the network.
>
> Due to the support issues, no provider in their right
> mind is going to use 1918 space for the middle-layer
> in a NAT444 scenario.

Hi Owen,

I wouldn't say -no- ISPs will use RFC1918 space for their NAT444
deployments. ISPs are a diverse bunch of folks. What's certain is:

1. Many if not most ISPs will use public scope prefixes inside the
NATted part of their deployments whether we provide a shared space for
it or not, and

2. Regardless of the disposition of 2011-5, the vendors and protocol
authors who made assumptions about NAT based on the assigned IP
address are about to get an object lesson in respecting the corner
case.

Regards,
Bill Herrin



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