[arin-ppml] ARIN-2011-5: Shared Transition Space for IPv4 Address Extension - Last Call

[Benson Schliesser]

On Apr 25, 2011, at 2:09 AM, William Herrin wrote:

> "A requirement for IPv4 addresses used solely inside a single
> autonomous system shall not qualify an organization to receive or
> retain an IPv4 address assignment or allocation."

In general, it's ok to ask ARIN staff to require use of the Shared Transition /10 when possible.  But I have a couple concerns about the practical enforcement.

Foremost, we must recognize that there are exceptions.  Some network designs may involve NAT (even CGN) and yet require globally unique addresses.  Other network designs may require globally unique addresses that are never routed outside of the AS.  I'm opposed to policy that disables organizations with such use cases.  And in the context of this policy, the language should be clear that the Shared Transition /10 is preferred but exceptions can be made.

Secondarily, the term "autonomous system" may not be useful in all circumstances.  In the Internet routing context (i.e. BGP) we have a fairly clear idea about how prefixes are associated with an AS / administrative domain.  But in other circumstances this isn't the case.  Examples include community of interest networks, VPNs with end-site NAT, etc.  And even in Internet routing, there isn't necessarily an obvious 1:1 org to AS relationship.

Cheers,
-Benson