[arin-ppml] Draft Policy 2009-2: Depleted IPv4 reserves

[Owen DeLong]

On Mar 24, 2009, at 8:48 AM, Matthew Wilder wrote:

> Hi Owen,
>
> I agree that there should be some amount of rationing of IP  
> Addresses in the IPv4 endgame.  I simply question the fairness of a  
> policy that says everyone can have what they need in IPv4 addresses  
> except those who need more than a /20 every 6 months.
>
> Fairness itself is a loaded word in these discussions.  To me,  
> fairness in this case fundamentally implies equal access to IPv4  
> addresses.  The question then becomes the definition of equal  
> access.  Is that access to an equal amount of space per  
> organization?  Though that sounds good, that answer ignores the  
> philosophy of needs-based allocations.  And what about equal amount  
> of space per EU organization represented by an ISP?  That would  
> imply that the large ISPs should still have access to the majority  
> of IP Addresses, since they represent the vast majority of internet  
> users in North America.
>
> The starting point for this policy has to be some kind of target  
> objective.  If the objective of the policy is to make the last /9 of  
> space last around one year before depletion, without consideration  
> of consistent limitation to vastly different organizations, I think  
> this policy fits the bill.
>
> I think there is a way of making the last /9 last for a year without  
> unequally affecting different organizations.  I think the way to  
> implement such a policy more fairly is to limit allocations to a  
> certain percentage of space an organization already has allocated to  
> it.  Thus, each organization can have equal geometric growth to  
> their IPv4 address space, and thus everyone has the same limitations  
> placed on them.  I don't know the numbers that would accomplish a  
> goal of 1 year spreadout of the last /9, but I would bet it is in  
> the 5-10% ballpark.  Note that this kind of policy would prevent a  
> run on ARIN by smaller ISPs and EUs that can request a /20 which  
> might double their IPv4 address space.
>
I think it would be closer to 1%.  Let's look at that in real terms,  
however.

For an organization that has an effective /10 worth of space, 1% is more
than 40,000 addresses.  On the other hand, for an organization that
has a /22, 1% is 10 addresses.  I really don't think the argument that  
this
is an equal impact on the small provider and the large one holds in such
a comparison. True, as a growth percentage, the effect is roughly the  
same,
but, in real terms, 1% of a /10 allows the large ISP to add a number of
large customers, lots of medium customers and/or a whole lot of small
customers. On the other hand, for the small provider, those 10  
addresses,
even if we're generous and bump them up to a /28 (16 addresses) to make
things line up are probably nearly useless.  First, they can only add  
one
small customer or a handful of home users.  Second, it's unlikely they  
can
even get the prefix routed, so, maybe they can't even do that.

Even if we use 10%, the numbers are still pretty skewed.  True, the  
small
provider now gets, essentially, a /25 to use for growth.  They might  
even
be able to put 8-16 small customers into that space.  There's even a  
small
chance they could get it routed.  But, the large ISP with a /10 under  
this
system gets a nice juicy /13 or so (more than 400,000 addresses).

However, with 24 x-large organizations (many of whom have more than
a /8, not just a /10 under their control) vying for this remaining /9,  
at
10%, I don't think you'll get anywhere close to a year.

You do raise some interesting questions.  It would be good to get a
sense from the community of:

1.	How long would the community like rationed IPv4 to last?
	A.	Brick Wall -- allocate as we have until it's gone.
	B.	Ration by some mechanism to last 1 year
	C.	Ration for 2 years
	D.	Ration for 5 years

2.	How would the community prefer to ration?
	A.	Percentage of existing space
	B.	Nobody gets more than a /x every 6 months
	C.	A graduated table based on your org. type:
			(example only:
					x-large		<=/18 every 6 months
					large		<=/19 every 6 months
					medium		<=/20 every 6 months
					smaller		<=/22 every 6 months
			)

3.	How does the community feel we should balance the conflicting needs
	of large quantities of addresses for large ISPs vs. large numbers of
	smaller organizations needing fewer addresses each?

I don't really have a strong opinion on how this should go.  But, I  
think it is
important we have the discussion and come to a deliberate decision as
a community in the near future.

Owen