[arin-ppml] ARIN-prop-127: Shared Transition Space for IPv4 Address Extension

George Bonser gbonser at seven.com
Sat Jan 22 17:48:23 EST 2011

> Remember, the limitations on LSN is the actual number of connections;
> however, you must still assign IPv4 addressing to all entities handled
> by the BRAS/CMTS. As IPv4 winds down, there will be (and many will
> to prepare for it), larger portions of the network served by common
> LSNs. This would utilize considerably more address space between CPE
> and
> LSN while at the same time serving fewer connections.
> Jack

There is no way to enforce who uses this and how.  Once the /10 is
allocated for this purpose, no communication with ARIN is required to
start using it.  In fact, an organization that does their own Internet
service could turn this into a defacto RFC-1918 net by numbering all
their internal nets in this space and there is no way to track it.  We
end up with what amounts to a private /10 that anyone can use at any
time for any purpose and many will.  Then you will run into exactly the
same collision issues you have with RFC-1918 space with this space.

Now one might argue that anyone who does that gets exactly what they
were asking for if such a collision occurs but maybe that doesn't happen
until years after the person that set it up has gone.  

So some genius sets up their network using a /8 for each of EU/AF, APAC,
NA/LATAM and bingo, you have the same problem that you were trying to
avoid and there is absolutely no way to enforce the proper use of such
address space.  Once it is allocated, anyone on the planet can use it
for what amounts to any purpose they want because it is "guaranteed" to
be no regionally routed and if they do their own Internet connectivity,
they will never see a collision from their upstream.

I am willing to bet a cheeseburger and a coke that as soon as that /10
is set aside that it will be used for unintended purposes.

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