[arin-ppml] ULA-C

David Farmer farmer at umn.edu
Wed Mar 31 21:16:47 EDT 2010

Fred Baker wrote:
> Dumb question.
> The complaint with ULAs as presently formulated is that there is a non-zero probability of them colliding.
> If you give a prefix to your favorite admin and have them number their network with it, and then re-assign the prefix to someone else, what's the probability that you have a collision?
> I think you need to accept that once put into use, a ULA will be in use by that administration permanently. You obviously see otherwise.  Fill me in?


- continuing or enduring without marked change in status or condition or 
- not capable of being reversed or returned to the original condition;

This may be an issue of semantics.

Your argument holds for GUA too.  The University of Minnesota has had since 1986.  For most practical purposes all allocations 
or assignments made by an RIR are at least semi-permanent.  But the 
community has taken the stance that GUA assignments or allocations are 
not permanent, so I believe we should take that same stance for 
centrally assigned ULA.

If you wish to use the word permanent when referring to GUA assignments, 
then using it for ULA would be appropriate.

I believe there is a consensus building at least here on PPML that ULA-C 
and PI should be thought of from a policy sense as identical, other than 
ULA-C is by convention not routed.

David Farmer               Email:farmer at umn.edu
Networking & Telecommunication Services
Office of Information Technology
University of Minnesota	
2218 University Ave SE	    Phone: 612-626-0815
Minneapolis, MN 55414-3029   Cell: 612-812-9952

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