[ppml] Policy Proposal 2007-16: Ipv4 Soft Landing - a simulationanalysis

Geoff Huston gih at apnic.net
Thu Jan 31 23:42:40 EST 2008

David Conrad wrote:
> Geoff,
> On Jan 31, 2008, at 3:22 PM, Geoff Huston wrote:
>> The key assumptions I've made are:
>> 1. For requests for additional IPv4 address space the requestor has
>> fully utilized their existing holdings at the point of the additional
>> allocation of address space.
>> 2. The distribution of new requestors who are requesting initial
>> allocations and requestors wishing a further allocation are largely
>> unchanged from that of the average of the past three years
>> 3. That the demand model is uniformly spread across the year.
>> 4. That the distribution of size of address requests is unchanged from
>> that of the average of the past three years.
>> 5. That the unadvertised pool of addresses has the same factors acting
>> on it that have been visible in the past 3 years - i.e. no change in
>> policies here.
> Would you agree that an additional assumption you make is:
> 6. Address utilization efficiency is unchanged.
> Implicit in Soft Landing is the assumption that there is non-trivial 
> inefficiency in the use of allocated address space, e.g., use of public 
> address space for infrastructure that could be numbered with private 
> space, fixed size assignments to customers based on pricing tiers, 
> unused but unrecovered assignments, etc.

I had wrapped this up in assumption 1. but its a valid point. The 
problem with this particular assumption is that there is no clear data 
at hand to determine the extent of this potentially recyclable address 
pool and the nature of the barriers the prevent its use under the 
current policy regime.

If this is a critical component of your policy proposal in terms of the 
impact of this policy on projected IP address consumption rates, then 
there is a significant problem here in attempting to quantify the 
potential outcomes of adopting the policy due to a lack of coherent and 
reliable data here. We could all make guesses I suppose, but without any 
solid foundation then frankly one guess is probably as good as any other 
as to how the policy would impact the address consumption trend data.



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