[arin-ppml] /48 per Site

TJ trejrco at gmail.com
Tue Apr 6 09:21:09 EDT 2010

> (Christopher Morrow): because I have 2 locations, one in NYC one in SFO.
>> Running a private
>> network link between them is more expensive than 2 commodity internet
>> links, I can't (today) expect longer than a /48 to pass through
>> inter-AS boundaries... so I need (now) a /47. Now, look at a business
>> like 'the Limited' who has (at last count) +1200 remote/disconnected
>> sites... they could need a much larger block than a /48, if they
>> wanted the benefits of easy multihoming/no-renumbering.
These remote sites probably don't host publicly reachable services, so a
simple "use PA addresses (/48 or even /56) and tunnel
to corporate" approach would work just fine, yes?  They could even be
multi-homed, but use something like GRE to have multiple concurrent tunnels
over different providers' addresses to get back to the hub.

>> Look at Allstate Insurance that had, at last count +10k remote
>> sites... a /48 is a single SITE, not a single ORGANIZATION.
And how many of those remote sites have, say, ~33k network segments?
(I only ask because ... well, see below)

> Note that none of the above colors the discussion about NAT nor
>> internal numbering schemes related to ULA*, I was simply pointing out
>> that it's entirely inaccurate to believe that 'Few Organizations will
>> need more than a single /48'.
"Few" is subjective.  Comparable to every company out there, yes - I think
"few" is an accurate term.  In absolute numbers, perhaps resembles a
different descriptor?

> (David Farmer): Could I please direct you to Draft Policy 2010-8 up for
> discussion in Toronto in less than two weeks, and specifically the following
> section;
> Initial assignment size
> Organizations that meet at least one of the following criteria are
> eligible to receive a minimum assignment of /48. Requests for larger
> initial assignments, reasonably justified with supporting documentation,
> will be evaluated based on the number of sites and the number of subnets
> needed to support a site.
> Organizations may request up to a /48 for each site in their network,
> with the overall allocation rounded up to the next whole prefix only as
> necessary. A subnet plan demonstrating a utilization of 33,689 or more
> subnets within a site is necessary to justify an additional /48 for any
> individual site, beyond this the 0.94 HD-Ratio metric of the number of
> subnets is used.

So an org with multiple "fairly large" sites (or that can draft an address
plan making it appear so ... ) can get multiple,
discrete, noncontiguous blocks.  Don't most networks of that size have their
own mechanism(s) for back-hauling traffic between sites?  I guess I am
trying to say that I don't see this solving a common problem ... happy to be
wrong though!

All assignments shall be made from distinctly identified prefixes, with
> each assignment receiving a reservation for growth of at least a /44.
> Such reservations are not guaranteed and ARIN, at its discretion, may
> assign them to other organizations at any time.
> Note: Organizations with multiple sites are encouraged to consider the
> use of /56s for smaller satellite sites.

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