Subject: RE: Why ULA-* will not harm the DFZ

From: "Azinger, Marla" <[email-masked]>
Date: Tue, 10 Jul 2007 17:17:13 -0400

Thank you Joe.  That is where my thoughts went with all of it and its nice to see it written out line by line.

There is just one point that needs to be considered as well, and that is what next?  While I believe ULA-Central should be used for private VPNs or internal infrastructure, I also ask everyone to consider the following:

1. Either designate space FC00::/8 as ULA-central and finish the documentation and processes needed (which their is a draft in front of IETF right now). 
2. Or release space FC00::/8 for another type of use (becuase sitting on the shelf is wasteful)
3. Or maybe double the size of statistically unique ULA.

Ok. Those are my thoughts.  Fire at will.
Marla Azinger
Frontier Communications

-----Original Message-----
From: Joe Abley [mailto:[email-masked]]
Sent: Monday, July 09, 2007 7:25 PM
To: IPv6 WG
Subject: Why ULA-* will not harm the DFZ

The risk to the DFZ of leaking ULA-* {routes, packets, whatever}  
keeps coming up on this list. I thought I'd try to address just that  
problem in isolation, just to see whether I'm hearing things right.  
Please attack the following.

1. With PI address space there is an expectation of global utility  
(or, reachability across the DFZ, or however you want to describe  
"useful on the Internet"). I said expectation, not guarantee.

2. With ULA-* address space there would be no expectation of global  
utility. In fact, there would be an expectation that the addresses  
are for local use only (for some definition of "local").

3. There is doubt that any ULA-* address space would be kept properly  
local in all cases. In fact, there is an expectation that {routes,  
packets, something} would leak.

4. If some leaks are tolerated, then maybe, eventually, all leaks  
will be tolerated. Let's assume that will happen, just to see where  
it takes us.

5. If everybody has non-PA addresses (be they PI or ULA-*) and they  
are all leaked to the Internet, then the DFZ will suffer state  
explosion.

6. If operators can distinguish between should-be-local addresses  
(ULA-*) and allowed-to-be-global addresses (PI) in ASICs then  
operators can filter in order to head off the cataclysm looming in (5).

7. Since people were told up-front that their ULA-* addresses were no  
good for use on the Internet, step (6) shouldn't cause anybody to  
lock and load their lawyers.

(6) and (7) above ring true for ULA-* but not for PI-for-all. So, ULA- 
* would not harm the DFZ in the way that PI-for-all might harm the DFZ.

Joe

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From: <[email-masked]>
Date: Tue, 10 Jul 2007 22:48:35 +0100

> sitting on the shelf is wasteful)

This is a good example of ossified IPv4 thinking. IPv6 is different from
IPv4. It is not just IPv4 with more address bits. It is not wasteful to
leave IPv6 address ranges sitting on the shelf any more than it is
wasteful to assign a /48 prefix to a homeowner.

--Michael Dillon

---

From: Joe Abley <[email-masked]>
Date: Tue, 10 Jul 2007 22:42:27 -0400

> wasteful to assign a /48 prefix to a homeowner.

In fact, I was thinking as I typed in my precarious train of logic  
the other evening that one of the nice features of IPv6 is that you  
can take an enormous chunk of addresses for use as an experiment like  
this, and not have to worry to hard about reclaiming them if the  
experiment turns out to go nowhere.

Joe

---

From: Mark Smith <[email-masked]>
Date: Wed, 11 Jul 2007 19:02:53 +0930

On Tue, 10 Jul 2007 22:42:27 -0400

> experiment turns out to go nowhere.

Exactly.

Convenience is a desirable characteristic, functionality is an
essential one.

With IPv6's large address space we have both convenience
and functionality.

We used to have both with IPv4 too, but then the Internet had to be
scaled to connect the world, so convenience had to go. By changing to
IPv6, we can now have it back.

Regards,
Mark.