[128144] in North American Network Operators' Group
Re: Addressing plan exercise for our IPv6 course
daemon@ATHENA.MIT.EDU (Saku Ytti)
Sun Jul 25 10:40:22 2010
Date: Sun, 25 Jul 2010 17:40:06 +0300
From: Saku Ytti <saku@ytti.fi>
To: nanog@nanog.org
In-Reply-To: <53955.1280068133@localhost>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On (2010-07-25 10:28 -0400), Valdis.Kletnieks@vt.edu and Mark Smith wrote
similarly:
> > http://www.wolframalpha.com/input/?i=1-((2^40)!)%2F((2^40)^1000000+((2^40)-1000000)!)+
> >
> > So if there are million assigned ULA's there is 36.5% chance of collision, if
> > formula is right.
>
> Bzzt! Wrong, but thank you for playing.
Point I was trying to convey is that you should not assume ULA to be
globally unique. Visibility of IP can extend past routing, for example
someone could use x-forwarded-for and assume rfc4193 to be as unique as any
other IPv6 address.
I personally have no beef with ULA and I don't mind that it can't be
trusted to be globally unique identifier. It'll still allow well planned
enterprise networks to avoid renumbering in M&A.
--
++ytti
