Todd Underwood was a little late

Lee Howard lee at
Fri Jun 18 18:42:49 UTC 2010

> -----Original Message-----
> From: Todd Underwood [mailto:toddunder at]
> firstly:  cgn puts reachability in the hands of a single organization.
>  with the PAP System you have a set of distributed choices about
> reachability:  different people can assess their different tolerance
> to certain kinds of unreachability.

Well, your proposal gives each "single organization" the same control
as CGN.
Except that if you announce somebody else's prefix, you're forcing
your neighbors to choose whether to accept your announcement or
the other organization's.

> as i said in the presentation, the probability that there will be
> positive operational overhead for a prefix is related the the count of
> reuse within an association domain for a prefix ( p(Oop) = Cr(Ap) ).
> We need to work out how to subdivide which parts of the internet
> actually want to communicate directly with each other reliably and
> make sure that they are within association domains.

Yes, exactly.  To minimize p(Oop), you need to consider what you'll
leak.  Generally, squat only when p(Oop) is very small, ideally when 
you can keep it all in.

But seriously (and less scatalogically), when organizations can't get 
IPv4 addresses from their RIRs, some are likely to try using numbers 
registered to other organizations.  In order of preference, they will use:
1) Globally unique, registered space
2) RFC1918 space
3) Space registered but unrouted (and unlikely to be routed) (see below)
4) Space registered and in use by someone very far away

"Registered but unrouted" would include space that is in use in large
private networks that aren't visible from your standard sources for
route views, such as U.S. DoD (6, 11, 22, 26, 28, 29, 30 /8) or U.K. 
MoD (25/8).  

I've heard that some organizations are growing beyond rfc1918 space 
and starting to use addresses like these already (for devices not capable
of IPv6) for internal networking (not publically routed).  I believe this 
is generally considered bad citizenship, but I'm interested in why?
Is there a range most people camp on?

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