[ppml] Policy Proposal 2003-10: Apply the HD Ratio to All Future IPv4 Allocations

[Member Services]

Many apologies, the subject and text in the first post are
mismatched.  Please disregard and use this one.

ARIN welcomes feedback and discussion about the following policy 
proposal in the weeks leading to the ARIN Public Policy Meeting 
in Chicago, Illinois, scheduled for October 22-23, 2003. All feedback 
received on the mailing list about this policy proposal will be 
included in the discussions that will take place at the upcoming 
Public Policy Meeting. 

This policy proposal discussion will take place on the ARIN Public 
Policy Mailing List (ppml at arin.net). Subscription information is 
available at http://www.arin.net/mailing_lists/index.html 

Member Services
American Registry for Internet Numbers (ARIN) 


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Proposal to apply the HD ratio to all future IPv4 allocations.

1. All requests for additional IPv4 address space shall require the
efficient utilization of all previous allocations including all space
reassigned to customers, if any.

2. The HD(Host Density) ratio of all previous allocations shall be greater
than or equal to .966 and the HD ratio of the most recent allocation shall
be greater than or equal to .930 in order to receive additional space.

3. The HD ratio is calculated as log10(utilized IPv4
addresses)/log10(totall addresses in all previous allocations). In this
formula, log10 refers to the base 10 logarithm.

Discussion of the proposal.

For more details on the HD ratio, please refer to RFC 3194
http://www.faqs.org/rfcs/rfc3194.html and to a proposal by Paul Wilson
posted to the APNIC mailing list on the 7th of August 2003
http://www.faqs.org/rfcs/rfc3194.html

The basic thrust of my proposal is to replace the rigid 80% usage
criterion by the more flexible HD ratio and to shift the emphasis away
from the last allocated block to include the total allocated address
space. To that end, the .930 criterion for the last block is a lot looser
than the existing requirements for the last block. This recognizes that
the economy is more dependent than ever on the smooth running of our
networks and we should not artificially force members to operate with
virtually no safety buffers for implementing new addresses.

Paul Wilson's paper contains ample discussions of the justification for
using the HD ratio. I prefer to retain the same name for the ratio as RFC
3194 and although I have proposed that we use the .966 number that he
suggests, I believe there may be valid arguments for reducing this
slightly, perhaps to .960.

It would be good for ARIN to have more detailed discussion of the HD ratio
on file however I don't believe that needs to be in the policy itself.
However, I would suggest that the ARIN website should contain a copy of
RFC 3194, a copy of Paul Wilson's paper, and a summary of any ARIN member
discussions regarding application of the HD ratio to IPv4 addresses.

Timetable for implementation

I suggest that this proposal should be implemented within 30 days of a
decision by a members meeting.


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Michael Dillon
Capacity Planning, Prescot St., London, UK
Mobile: +44 7900 823 672 Internet: michael.dillon at radianz.com
Phone: +44 20 7650 9493 Fax: +44 20 7650 9030