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Re: draft-ietf-v6ops-addcon-03.txt ... ULAs of shorter-than-/48 and ULA multicast scope matching ...



Le vendredi 16 mars 2007 19:10, Tim Chown a écrit :
> > A /48 ULA would do just fine. They aren't going to be in short
> > supply.
>
> I would assume doing that would affect the collision probabilities?

This is about ULAs, that are not supposed to become part of the public 
Internet ever. As such, I will assume that it is the probability which 
matters, is that of a conflict between my network prefix and my 
girlfriend's prefix, or BigCorp's prefix and GrossFirma's prefix or 
FooPublicBureau's and BarStateAgency's. However, the probability that 
there is one or more conflict between all of the existing (but 
disconnectd) ULAs is not an issue.

If I'm not mistaken, the probability of two uniformly random /48 
colliding is exactly the same as (2^8)² = 65536 times the probability 
of two /56 colliding. That is to say under 10^(-12) for the whole 
fd00::/8. So, yes, it's much bigger, but that's merely in proportion to 
the number of possible prefixes.

This shall not be construed as an endorsment of /48 by me.

-- 
Rémi Denis-Courmont
http://www.remlab.net/