[arin-ppml] GUA vs ULA vs ?

michael.dillon at bt.com michael.dillon at bt.com
Tue Mar 30 04:32:04 EDT 2010

> - 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

In this glossary
and in several Internet drafts, GUA means Global Unicast Address.
The IETF has allocated the range 2000::/3 for use as Global
Unicast Addresses. 

Please let's avoid creating new acronyms that are not
absolutely necessary. 

> If the community decides that ARIN, not IANA, should provide 'private'
> space, it should:
> - be from a large block designated as such.

RFC 4193 has already designated FC00::/7 for this purpose.

> - 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 work

Cymru currently references someone else's IPv6 bogon list here:
And it doesn't mention FC00::/7

> 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. 

That's not true. 
a) ARIN does not deal with ULA's currently so there is no
cost at all, nor is the cost known
b) ULA's would have to be handled by a global registry so
there is potential for costs to be shared with other RIRs
thus making them less than GUA allocations.
c) costs and fees are not part of ARIN's policy. They are
determined by ARIN members and the Board of Trustees.
d) the cost of operating a low volume automated registry
is likely to be so low that it is dwarfed by comparison
with other ARIN activities.
e) I suspect that the main costs of ULA-C will be in maintaining
a relationship with the registrants and checking with them
once a year to see that they still exist.

--Michael Dillon

More information about the ARIN-PPML mailing list