I would change it from requirement for HD Ration to optional choice to use HD ratio to determine utilization when requesting additional ips. Here is what I would prefer for text for that policy proposal: --- 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. When requesting additional ip blocks ISP Members and other organizations with direct ARIN allocations and assigments may choose to have its utilization counted by means of HD Ratio, otherwise RFC2050 utilization guidelines should be used by ARIN 3. The HD ratio is calculated as log(utilized IPv4 addresses) divided by log(total addresses in all previous allocations). In this formula, log refers to the natural logarithm. 4. Efficient Utilization per RFC2050 guidelines requires 80% utilization of ip blocks, ARIN will verify this by requesting utilization statistics for one or more previously assigned or allocated ip blocks. --- This way we do not all of a sudden change everything and at the same time those that want to use HD Ratio would be free to do so. ARIN may also try to promote HD ratio if it likes it by informing whoever requests ip block that they have this choice, etc. On Mon, 9 Feb 2004 Michael.Dillon@radianz.com wrote:
I'm going to present the following policy change at the ARIN meeting in April. In a few days I have to submit the exact wording to ARIN and I'm looking for comments before I do this. Basically this policy loosens the rigid 80% utilization requirement in a progressive fashion to recognize the inevitable overhead of hierarchy in larger networks.
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 log(utilized IPv4 addresses) divided by log(total addresses in all previous allocations). In this formula, log refers to the natural logarithm.
Rationale:
The HD ratio was proposed as a way to determine allocation usage thresholds for IPv6 address allocations. For more details on this, please refer to RFC 3194 <http://www.faqs.org/rfcs/rfc3194.html>. There is some detailed background discussion about applying the HD ratio to IPv4 allocations in a
proposal by Paul Wilson posted to the APNIC mailing list on Aug 7, 2003
http://www.apnic.net/mailing-lists/sig-policy/archive/2003/08/msg00000.html and he presented the it to the annual APNIC policy meeting using these slides http://www.apnic.net/meetings/16/programme/sigs/docs/policy/addpol-pres-wils... I am not suggesting that ARIN should adopt the APNIC proposal and although Paul invents a new name for the HD ratio, I prefer to keep the original term.
The basic thrust of this 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 is because the utilization threshold
establishes a time buffer between the beginning of an ARIN application for
additional addresses and the final deployment of new addresses in the operational network. By using a looser criterion as network size grows, we
are also expanding this time buffer. This recognizes that the economy is more dependent than ever on the smooth running of our networks and we should not artificially force larger members to operate with virtually no safety buffers for implementing new addresses. This safety buffer size is important because larger networks have more involved processes for changes to their network and these processes take time.
Paul Wilson's paper contains ample discussions of the technical justification for using the HD ratio. 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.
------------------------------------------------------- Michael Dillon Capacity Planning, Prescot St., London, UK Mobile: +44 7900 823 672 Internet: michael.dillon@radianz.com Phone: +44 20 7650 9493 Fax: +44 20 7650 9030