[ppml] Summary of Trial Balloons for Dealing with IPv4 Address Countdown
Iljitsch van Beijnum
iljitsch at muada.com
Tue Apr 3 14:22:12 EDT 2007
On 30-mrt-2007, at 23:34, Jim Weyand wrote:
> I find myself struggling with how to convert the suggestions and
> comments on this list into actual policy proposals.
Perhaps it would be a good idea to see if we can agree on what our
goals and assumptions are. An important question is whether it's a
good idea to try and postpone the moment when the RIRs have to turn
down requests for lack of free address space. Assuming we still have
around five years, and that a great deal can be accomplished in that
time, is it worth going through a lot of trouble to buy us a limited
number of additional years?
> 4) Several similar informal proposals to encourage recycling by
> empowering ARIN to more actively police the use of IPv4 addresses by
> various means
> 6) An informal proposal to ask holders of unused address IPv4
> addresses to voluntarily return the addresses
A "use it or lose it" policy would make sense. Large amounts of
address space aren't visible on the global internet, so either people
aren't using it at all, or they're only using it internally. If we
set a deadline by which address space must be "in use" (hard to
define) or it will be put at the end of the free list, this gives
people who are using it for internal purposes a reasonable amount of
time to move to something else.
> 7) Several variants of informal proposals to start assigning
> space with IPv4
> 8) An informal proposal to get endusers to demand access to IPv6
> networks by creating a media storm similar to Y2K.
The depletion of IPv4 and the adoption of IPv6 are largely orthogonal
in the short term. Having IPv6 doesn't mean you don't need IPv4 any
more, not having IPv4 doesn't make IPv6 more useful.
This is what I suggest:
In my opinion, it's a problem that the RIRs are giving out extremely
large blocks of address space to the world's largest ISPs. For
instance, Softbank has a /8, Comcast got a /8 in two installments and
French, Deutsche and British Telecom all have multi-million sized
blocks. Even very large ISPs need some time to put these amounts of
address space to use, so what happens is that at various intervals,
new large blocks are requested, so the number of addresses given out
in any particular year varies widely because one request can be as
much as 5 to 10 % of the yearly world-wide use. So giving out large
blocks makes making predictions harder. Another problem is that if
and when business stalls, a good part of a large block will go
unused. For both of these reasons, it's a good idea to limit the
maximum block size that is given out *today*.
When we start to run out of address space for real, this only gets
worse, and we run the risk that a large request clears out the
remaining address space in one go. To avoid this, we should adopt a
policy where there is a maximum block size, and a minimum interval
between obtaining address blocks. As the number of addresses left
gets smaller, the maximum block size is reduced.
For instance, we could make the maximum block size 2 million and the
minimum interval 2 months. So if an ISP thinks they need 16 million
addresses in a year, they'll have request 2 million, wait 2 months,
request another 2 million and so on.
In 3 or 4 years, the limit could be half a million, so someone
needing 16 million addresses would only be able to get 6 x 1/2
million = 3 million. (Note that people who need smaller blocks still
get what they need.) The effect is that an ISP who signs up 16
million new users each year will then have to share an IPv4 address
over several users, where the number of users per address increases
every year, rather than that in year X every user can get their own
address and in year Y there's nothing left.
The maximum block size could each year be set to (for instance) the
next higher CIDR boundary of 0.1% of the remaining IPv4 address space.
This policy has the important property of being predictable so people
can plan rolling out new technologies to deal with the IPv4 address
shortage in ways that fit their business.
A problem would be that this works per-organization, so it favors
smaller organizations over larger ones.
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