[ppml] Policy Proposal: IPv4 Soft Landing

[Scott Leibrand]

Iljitsch van Beijnum wrote:
> On 11-mei-2007, at 10:14, Member Services wrote:
>   
>> 30 days after specified thresholds in the amount of address space
>> remaining in the IANA IPv4 free pool are crossed, the requirements
>> necessary for ISPs to obtain additional IPv4 address space are made
>> more stringent
>>     
>
> The effect of a policy like this is that:
>
> a. IPv4 becomes more painful to use because addresses are harder to get
> b. the incentive to move to IPv6 is reduced because the moment that the
>     IPv4 is completely depleted is postponed
>   
As written, those two statements appear to contradict each other.  To 
put it in economic terms, the effect of a policy like this is that:

    * IPv4 becomes more expensive (though additional work required)
      because addresses are harder to get
    * as the cost of IPv4 growth goes up, IPv6 will become a
      cheaper/easier alternative for a number of orgs (for some earlier
      than others)
    * as some orgs switch their growth over to IPv6, the moment that
      IPv4 is completely depleted is postponed.  This delays the
      increase in IPv4 cost (through slower triggering of IPv4 Soft
      Landing thresholds), and allows more time for the cost of
      deploying IPv6 services to come down (through natural replacement
      of old IPv4-only gear with new IPv6-capable gear, and by giving
      people time to learn IPv6)

To re-use a recently proposed analogy, let's say that 5 years from now a 
major war starts in the Middle East, and a good majority of the oil 
extraction infrastructure is destroyed..  The US has to decide how to 
use the Strategic Petroleum Reserve (SPR) in order to minimize economic 
disruption while consumers switch to alternatives, such as transit, 
telecommuting, biofuels, the use of plug-in hybrids (PHEVs), and 
producers ramp up production from more expensive sources.  Two 
strategies are proposed.  In the first, the government proposes to 
release oil from the SPR (under today's replenish-it-later terms) to any 
refiner who needs it until the SPR is exhausted.  In the second, they 
set thresholds for gradually increasing the price of oil from the SPR as 
the reserve is used up.

In the first scenario, which I believe is analogous to leaving IPv4 
allocation policies unchanged until the free pool is exhausted, you 
would see the following:

    * Much ado would be made about the need to make PHEVs, flex-fuel
      vehicles, and biofuels more available, and to encourage their
      use.  Car-makers (vendors) would be encouraged to design and start
      producing PHEVs and flex-fuel vehicles, and some consumers would
      start buying them right away.  The price of gas would go up, and
      consumers would start to change their behavior, but gasoline would
      still be available for several months, so many consumers who can
      still afford gas continue to take advantage of the
      now-less-congested roadways and drive to work as before.  Biofuel
      producers would attempt to ramp up production capacity, but would
      initially be competing with fuel produced from the oil in the SPR
    * As the SPR is exhausted, there would be increasingly frantic
      discussion about the need for people to prepare for the impending
      shortage.  This would encourage some additional consumers to start
      changing their behavior, but other consumers ignore the lectures
      and continue on as before.
    * Once the SPR is exhausted, gas prices shoot through the roof, and
      shortages start to be seen at gas stations.  The consumers who
      have continued relying on their traditional automobiles suddenly
      realize they have to do something, and frantically start trying to
      change their behavior.

In the second scenario, which I believe is analogous to the IPv4 Soft 
Landing proposal (or a similar policy), you would see the following:

    * The same calls for PHEVs, biofuels, etc. would be made.  The price
      of petroleum-based fuels would start to rise more rapidly than
      under the first scenario, as oil from the SPR becomes more costly.
    * The biofuel producers would quickly find that they have a cost
      advantage over petroleum fuel, and would invest more rapidly in
      increasing production.  Auto makers would see their sales switch
      over to nearly 100% PHEVs and flex-fuel vehicles, so they would
      ramp up PHEV production much faster, and convert all their other
      factories to producing flex-fuel vehicles.  Mass transit providers
      would see their ridership rapidly increase, and would rapidly
      start adding buses and trains to their existing fleets.
    * As consumers switch away from petroleum-based fuels, the
      exhaustion of the SPR would slow.  Eventually oil prices would
      settle to a new higher equilibrium, and the SPR probably would not
      be exhausted completely.  Shortages of gas would be rare.
    * Some would argue that the government should've released more oil
      from the SPR to reduce the impact of the switch away from oil, but
      others would recognize that by applying the "Soft Landing" policy,
      major disruptions and shortages were averted, and the switch away
      from oil was accomplished at a much lower cost to the economy than
      originally predicted.  (For other examples of that, see the
      results of the sulfur dioxide cap-and-trade program.)


> c. in many cases, the same amount of address space as before is given  
> out,
>     but now as many small blocks, increasing the ARIN workload and  
> hindering
>     route aggregation
>   
This is a different concern that we'll need to keep an eye on and 
possibly address.  I'm not sure the deaggregation under Soft Landing 
would be any worse than that under a Hard Landing.  As mentioned by 
others, we are likely to see a lot of deaggregation of existing 
allocated-but-unrouted space as exhaustion nears.  It's possible that 
Soft Landing may reduce that, offsetting the additional routing table 
load from smaller allocations.
> As such, a policy like this doesn't seem to be in the best interest  
> of the internet community at large.
>   
As you can tell, I think that a policy like Soft Landing that attempts 
to provide incentives for people to gradually move their growth away 
from IPv4 will help ease the disruption of the transition.  As such, I 
believe that a proposal like Soft Landing is much better than the 
alternative of continuing existing policy until the unallocated IPv4 
pool is exhausted.


-Scott