[arin-ppml] efficient utilization != needs basis

[michael.dillon at bt.com]

> Please note I am not saying they are not routable, they are 
> most assuredly intended to be routed within an Autonomous 
> System or even within a small set of Autonomous Systems.  

This small set can be as much as several hundred ASNs.

> But, that they are not intended to be routed across the 
> entire hierarchically routed global Internet.  In other 
> words, by default the normal expected behavior for a network 
> operator is to not route these across an Autonomous System 
> boundary without special arrangements.

That is an odd way of putting it. These blocks are intended
to be routed across ASN boundaries but the network operator
typically maintains separacy between their public Internet
infrastructure and the COIN (Community of Interest Network)
infrastructure. Even the automotive industry, which does not
have the same security needs as air transport or finance,
requires the ISPs to use a separate infrastructure for ANX
traffic. Let's put it this way, if company A is a member of
a COIN supplied by ISP B, the Company A will buy a separate
circuit from ISP B to supply Internet access. The COIN does
not meet the Internet except internally in the member company
networks where there are usually strict controls in place
including routing, firewalls, edge ACLS to make sure traffic
does not leak onto the wrong network.

COIN IP address blocks are indeed routed across the entire
hierarchically routed global internetwork of the COIN.

> But because they have an intended scope that is meant to 
> encompass multiple Autonomous Systems I believe that use of 
> IPv6 Global Unicast addresses are appropriate.

Yes.

> So, a question I have for you and something I'm not 100% 
> decided on would ULA-Central or ULA-Global be an acceptable 
> alternative?

I suspect that the only acceptable alternative would be one
in which the IETF recognizes the existence of multiple 
global internets, not just the one with the big I, and sets
aside special Global Unicast prefixes for these COINs. And
to get there, at minimum they would have to get the agreement
of the air transport folks, the automotive folks and the global
financial industry folks.

It seems easier to just use ordinary global unicast.

--Michael Dillon