Applying HD Ratio to all IPv4 allocations

[Michael . Dillon]

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 . 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/msg0.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-wilson-hd-ratio.pdf
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 672Internet: [EMAIL PROTECTED]
Phone: +44 20 7650 9493Fax: +44 20 7650 9030

Re: Applying HD Ratio to all IPv4 allocations

[williamelan.net]

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 [EMAIL PROTECTED] 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 . 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/msg0.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-wilson-hd-ratio.pdf
> 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 672Internet: [EMAIL PROTECTED]
> Phone: +44 20 7650 9493Fax: +44 20 7650 9030