[arin-ppml] GUA vs ULA vs ?

Steve Bertrand steve at ibctech.ca
Mon Mar 29 20:47:25 EDT 2010

I am overwhelmed with the number of posts regarding the whole
'Non-connected networks', so I'll admit freely that I haven't been able
to keep up.

With that said, I would like to share my opinion(s), even if they
conflict, overlap, or otherwise override what others may have said.


- I am in favour of eliminating NAT from IPv6
- I do have experience in dealing with both the ISP environment, and the
small-medium enterprise (across multiple boundaries), so I do see the
'value' of NAT (I use the term 'value' loosely)
- Since I have dealt with both sides, I am willing and able to drop all
bias toward NAT for the purpose of this discussion
- I want what is best for everyone


- I'm a bit behind the curve on some of the abbreviations, but I believe
that this is correct:
--- ULA == Unique Local Address
--- GUA == Global Unique Address

If that is the case, here is how I feel...

We'll assume that I want to try to exploit a weakness in the policy to
garner space that I'll "say" won't be routed, but thinking that I'll
route it eventually anyways.

If the community decides that ARIN, not IANA, should provide 'private'
space, it should:

- be from a large block designated as such.

--- why?

- So that the maintainers of BOGON lists (eg: Team Cymru) can hold one
slot in their filters for all entrants, ensuring that enough staggered
and unpredictable routing breakage will occur to ensure that serious
network engineers/architects will realize that the `cheap way out' won't

- as has been said, ARIN is not a routing policy maker. However, if
someone has a block allocated by ARIN that is 'supposed' to be private
(ie. not globally routable) but it happens to show up in the DFZ, then
it costs me. Perhaps it costs me for the extra tax hit I pay on my
filter list, or if I choose to not be diligent, a slot in my routing table

Although I want the barrier-to-entry for IPv6 to be very low, I don't
like the idea of ARIN supplying ULA, unless it sits equal in cost to
GUA, and unless ARIN can supply it in a way that facilitates a very
simple method for third parties to (help) ensure that the ULA will never
appear in the DFZ.

Otherwise, the way I see it, is that the cost of my /32 has the same
administrative costs to ARIN as someone else's ULA. If ARIN doesn't
achieve a lower administrative overhead to managing the different IP
space, then the price should be equal.

Perhaps IANA should be approached for a 1918 v6. Perhaps I'm out of my
league ;)


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