[ppml] Summary of Trial Balloons for Dealing with IPv4 AddressCountdown

Alexander, Daniel Daniel_Alexander at Cable.Comcast.com
Fri Apr 13 14:05:19 EDT 2007


Sorry for the late response, but I am having a hard time keeping up with
this mailing list. I just wanted to clarify a point you made below about
one of the allocations. Comcast actaully received that address space in
three installments over an 18 month period. The first was in April of
05, with the last piece of the /8 being allocated in 12/06. All ISP,
regardless of size, are still bound by the timeframe policies in every
RIR. The size of any ISP's request can only be for what they can
justifiably use within a certain timeframe. For the ARIN region it is
currently six months. So while we ended up with the whole /8, we were
only given it because we actaully put it to use over a now, two year
time frame.

The problem with a size restriction is that is doesn't change demand. It
will only cause ISP to submit more applications, more often with the end
result being the same. If you use a million IP for your customers in a
year, the only difference between two applications in that year or a
dozen, is the amount of administrative work that is done to process the


-----Original Message-----
From: ppml-bounces at arin.net [mailto:ppml-bounces at arin.net] On Behalf Of
Iljitsch van Beijnum
Sent: Tuesday, April 03, 2007 2:22 PM
To: Jim Weyand
Cc: ppml at arin.net
Subject: Re: [ppml] Summary of Trial Balloons for Dealing with IPv4

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  
> IPv6
> 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

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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