[ppml] Defining Utilization of IPv4 addresses

Michael.Dillon at radianz.com Michael.Dillon at radianz.com
Wed Feb 11 06:38:25 EST 2004

Yet another policy proposal that will be submitted to ARIN
in the next few days. Comments?

1. When an ISP applies for IPv4 address space, ARIN analyzes the
   utilization rate of any existing IPv4 address blocks allocated 
   to the ISP.

2. For the purposes of calculating the utilization rate, any IPv4
   address range that is assigned or allocated to another organization
   will be counted as utilized if it meets the following two conditions.

3. The assigned or allocated address range must be of a size that is
   justified by ARIN policy.

4. The ISP must require the other organization to use their addresses
   efficiently using VLSM and CIDR technologies.

5. The utilization rate of an address block is calculated as the 
   number of utilized addresses divided by the total number of 
   addresses in the block.


Currently, there is no clear definition of utilization in ARIN's IPv4
policy. The result is that different organizations interpret this in 
different ways. This policy change is an attempt to level the playing
field so that noone has an unfair competitive advantage due to the
vagueness of the policy.

This policy change only provides a clear definition for the utilization
rate of address blocks allocated by ARIN to ISPs. It does not address the
utilization rate of address blocks assigned to end users which would
presumably be calculated differently by counting end devices, network
and broadcast addresses.

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

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