[ppml] IPv4 wind-down

michael.dillon at bt.com michael.dillon at bt.com
Wed Mar 21 06:58:24 EDT 2007

IPv4 wind-down is the natural running-out of the IPv4 space, as opposed
to some manufactured countdown process.

>     The RIR's, in order to assure the orderly shutdown of IPv4
>     allocations should do their best to predict the date at which
>     there will be no more IPv4 addresses available, 

That's not policy. Maybe you should make a suggestion at:
https://app.arin.net/suggestion/ and the BoT will instruct staff to do

> - There is a well known date at which no more IPv4 space will be
>   available, making it easier for those needed addresses to show their
>   management the need for alternate plans.

I don't believe a policy is needed for this, just better publicity of
the fact that IPv4 addresses are running out SOON where SOON is defined
as "within the normal timeframe for mid-range corporate planning". The
stats that have been published to date tend to be dry and lifeless
things written by people who are more comfortable with data than with
the English language. We don't need policy to fix this.

> - By the RIR's shutting down distributions of addresses at the same
>   time it prevents the "last RIR standing" from being swamped by every
>   international company solely because they still have addresses.

Why is this a problem?

> - We may leave some IPv4 space unused that could otherwise be put to
>   good use.

This seems foolhardy in the extreme and if my company was in need of an
additional allocation at that time, I would certainly refer this issue
to our legal department to see if we could challenge ARIN/ICANN in
court. We all know there will be hardship when the food runs out, but,
like the British landlords in Ireland during the potato famine, you want
to keep grain in the storehouses while the peasants starve. 

> - Reclamation of unused address space.  It doesn't matter if 
> we do this
>   or not, all predictions are we still run out of address space.

However, it would be good to have a reclamation discussion in some
forum. There are varying levels of reclamation. IANA/ICANN could reclaim
some space such as class E addresses, some of the loopback block, and
portions of early network number allocations that are not fully used.
The RIRs can reclaim addresses by auditing all allocees and assignees to
see if they still are using those addresses. Individual companies can
reclaim addresses, perhaps by shuffling them around internally with lots
of internal /32 routes. Or by renumbering to get a better internal
aggregation scheme in place. These possibilities whould all be
documented, along with estimates of the amount of addresses recoverable.
In some cases we might be able to publish some best practices for
reclamation and reuse of addresses in individual networks.

> - Encouraging people to use less IPv4 addresses, including but not
>   limited to higher fees, required use of NAT, 

ARIN should never promote shifting to IPv4 NAT without promoting a shift
to non-NAT IPv6 at the same time. Yes, there are tradeoffs and the IPv4
NAT solution may be more expedient, however both options should be
fairly presented. I don't want to see ARIN pushing NAT.

--Michael Dillon

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