[ppml] Utilization

Leslie Nobile leslien at arin.net
Thu Feb 12 16:45:15 EST 2004


We have been following this discussion and thought that it might be useful
to the community if we clarified several points as they relate to current
ARIN practice and policy.  

(ARIN comments begin with ***)

-----Original Message-----
From: owner-ppml at arin.net [mailto:owner-ppml at arin.net] On Behalf Of
Michael.Dillon at radianz.com
Sent: Thursday, February 12, 2004 11:38 AM
To: ppml at arin.net
Subject: [ppml] Utilization

In response to Lee:

I agree that this proposal is more complex than it should
be. I wish that the current policy had numbered paragraphs
so that I could clearly and concisely refer to it rather
than trying to restate it. Let me start again by posting
the current wording (slightly changed) and then
list a number of explanatory points.

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

*** Utilization rate is not entirely correct terminology as it actually
refers to how fast IP address space is used over time.  In its analysis of
how an IPv4 address block is used, ARIN looks at overall utilization,
including the percentage of space used, and the amount of time it took to
use that space (the utilization rate).

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

*** Under current policy, when reviewing overall utilization, ARIN looks at
sub-delegations made to the ISP's services (i.e. DSL, dial-up.),
web-hosting, and infrastructure, in addition to reassignments and
reallocations made to other organizations.

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, in particular by 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.

*** The total utilization percentage is currently calculated this way.


Leslie Nobile
Director, Registration Services
American Registry for Internet Numbers (ARIN)

Note the following points:

a) This policy is for ISPs, i.e. organizations
   who receive an allocation from ARIN and then
   transfer chunks of the allocation to other parties.

b) The utilization that we are measuring refers
   to the allocation received from ARIN.

c) We don't care whether a subset of the allocation
   is assigned or allocated to another party. For the
   purposes of calculating utilization they are 

d) We don't want to supersede other restrictions
   on allocations and assignments so we impose two
   conditions which attempt to echo the existing

e) Point d above would be unnecessary if we could
   simply refer to numbered paragraphs.

f) The first condition says that we are not usurping
   the existing requirement to justify an allocation
   or an assignment.

g) The second conditon says that we are not usurping
   the existing requirement for a transitive
   technical AUP.

h) The final clause could be considered redundant 
   because once we have defined "utilized" the
   rate calculation should be obvious. However
   I believe that there is value in making the
   calculation explicit so that tool implementors
   have a reference that maps easily into programming

i) I don't want to incorporate a few wording changes
   into existing policy. I want to explicitly say
   what we mean by utilization and how we measure it
   in an unambiguous way because the existing policy
   is interpreted differently by different ISPs.

j) I also want a clear definition for IP address
   management tool vendors who may have incporporated
   different calculations in their tools.

I could probably deal with references to the existing
policy in a better way. I'll think about that. And
I didn't mention broadcast and network addresses because
those are used in calculating utilization of an assigment
by end users, i.e. leaf nodes in the hierarchy.

--Michael Dillon

More information about the ARIN-PPML mailing list