[ppml] Allocation and reallocation

Charles Scott cscott at gaslightmedia.com
Mon Oct 27 17:07:08 EST 2003

  Note that most of these policies say that the end-user must have 
"efficiently utilized" 80% ...  I take this to mean that 80% of the space 
is deployed in the network, not that 80% of all possible addresses are 
assigned to hosts. I suppose then that I could have been causing trouble 
for no reason if one accepts that no ISP would hold a customer to having 
80% of their address space assigned to specific hosts (or broadcast 
addresses). If you look at it that way, a subnet that has 25% of the 
addresses in use currently and will have 50% in use in one year is being 
efficiently utilized and that entire sub-net is ticked off against the 80% 
utilization of the assignment. 
  RFC2050, which is the stated basis for the ARIN policy is pretty clear
(as mud) that the reccomendation end-users is the 25%/50% guideline and
that the 80% criteria only applies to reassignemnt. So, I can't see how
anyone would hold any end-user to 80% host utilization of a netblock.
What's left to the imagination is what the 25%/50% guideline means. Is 
that applied accross the board for the number of host addreses in use in 
the entire assignment, or is that per sub-net in use. If it's applied 
accross the entire assignment, then the H/D ratio would be a better 
indication of efficient utilization (only for end-user utilization of 

Chuck Scott

On Mon, 27 Oct 2003, Leo Bicknell wrote:

> In a message written on Mon, Oct 27, 2003 at 12:01:21PM -0600, Rob Vinson wrote:
> > That has always been my take. I know whenever customers have asked me to
> > expand their /28 to a /27 (or whatever) - I ask them to show 80%
> > utilization. It's also in our AUP. Wrong or right, end user accountability
> > makes it easier for me to validate a new /20 request. 
> Following up on Rob's 80%...some google found the following:
> http://www.netsonic.net/ip-alloc-policy.php
> http://www.stickdog.com/ippol.phtml
> http://www.hostdepot.com/Company/Policies/IPAddress.asp
> http://www.more.net/technical/netserv/tcpip/ipreq.html
> http://www.imagina.com/support/ipjust/ipjustguidelines.html
> http://www.coop.net/about_us/government/policy/addresses.php
> http://www.onsitenj.com/dialup/faq/ip_allocation_policy.htm
> It would seem a lot of ISP's out there are holding end-users to an
> 80% rule.  If that's wrong we need to fix something, because 
> lots of people are getting the wrong idea.
> -- 
>        Leo Bicknell - bicknell at ufp.org - CCIE 3440
>         PGP keys at http://www.ufp.org/~bicknell/
> Read TMBG List - tmbg-list-request at tmbg.org, www.tmbg.org

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