[arin-ppml] ARIN-prop-127: Shared Transition Space for IPv4 Address Extension

Jack Bates jbates at brightok.net
Sat Jan 22 16:02:49 EST 2011

On 1/22/2011 2:22 PM, Frank Bulk - iName.com wrote:
> If current policy allows for IPv4 requests to be fulfilled based on the need
> for numbering a CGN network, I would be willing to support an amendment to
> prop-127 that would nullify this justification, but that's about as far as I
> think we can go.  Please correct me if I'm wrong, but I don't think ARIN
> mandates the use of specific type of addressing within a member's operation;
> the closest concept I could find is micro-allocations.
I don't see where current policy would forbid it. This restriction to 
justification is a safety measure to insure the /10 has maximum effect 
when dealing with CGN networks. It would not prohibit them from using 
RFC-1918 either.

ARIN has not normally mandated specific address types, as there is a 
limitation in types. I suspect that using class D addressing as a 
justification for an allocation might be met with some resistance. This 
/10 allocation is a new type designed to meet a specific need by ARIN. 
The policy still will not mandate the use of CGN; only mandate that you 
cannot use the addressing behind the CGN in your IPv4 address 
justifications (though they are still technically applicable to IPv6 
justifications, though not directly since we gauge IPv6 differently).

Case in point. Some networks, despite being behind NAT (or are 
completely isolated without NAT) utilize globally unique addressing 
internally to deal with interconnecting networks. It is these private 
interconnections that justifies the use of globally unique addresses 
even though the networks will not be publicly routed. CGN works on a 
completely different premise and is based on non-unique addressing. As 
such, we need to insure that we recognize this and don't allow 
justification to apply to the internal side of a CGN.

We could, I believe, even take it a step further and mandate a ratio for 
CGN in the public side justifications (I believe this was done for modem 
bank ratios at one point?). Such a mandate would fit in a different 
policy proposal, though. Not this one.


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