[ppml] Host-Density Ratio

[Michael.Dillon at radianz.com]

In a few days I will be submitting a formal proposal for a policy which 
adopts the
host-density ratio for IPv4 allocations to replace the current fixed 80% 
utilization rate. At the last meeting, there was a lot of confusion over
the meaning and complexity of the H-D ratio and I hope to clarify things
much more this time, both before and during the meeting. In any case,
I welcome comments on my proposed wording for the policy which is
slightly changed from last time.

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

2. The HD(Host Density) ratio of the sum total 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(total 
   addresses in all previous allocations). In this formula, log10 refers 
to 
   the base 10 logarithm.

Rather than go into detailed explanations at this point, I will just give 
you three
URLs that explain the concepts in a lot more detail

Original IPv6 idea http://www.faqs.org/rfcs/rfc3194.html

Paul Wilson's APNIC proposal
http://www.apnic.net/mailing-lists/sig-policy/archive/2003/08/msg00000.html
and his APNIC 16 presentation
http://www.apnic.net/meetings/16/programme/sigs/docs/policy/addpol-pres-wilson-hd-ratio.pdf

At the APNIC policy meeting there was a consensus in favor of the HD ratio 
but 
people felt it should be discussed more broadly, both in other RIR regions 
and
within the APNIC countries.

In particular, I am considering dropping point number 1 since it is 
supposed to be
already part of the IPv4 policy. Personally, I think that adding in "the 
sum total" makes
the statement more explicit than the existing one, but I could be 
convinced that it
is unnecessary.

Point 3 seems to be rather straightforward and uncontroversial

That leaves point number 2. Does anyone see any flaws in this?

--Michael Dillon


-------------------------------------------------------
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