[address-policy-wg] 2007-05 New Policy Proposal (IPv6 ULA-Central)

At 11:08 PM 4/05/2007, Wilfried Woeber, UniVie/ACOnet wrote:
>Geoff Huston wrote:
>
> > On 5/4/07, Gert Doering <gert at space.net> wrote:
> >
> >>
> >> Hi,
> >>
> >> On Fri, May 04, 2007 at 11:54:22AM +0200, Shane Kerr wrote:
> >> > The motivation for a version with a central registry however is not so
> >> > obvious to me. The only justification I can think of is that you can
> >> > be sure not to pick the same /48 as someone else has picked. But the
> >> > chances of that are *billions* (that's "thousands of millions" to
> >> > British folk) to one!
> >>
> >> Take the "birthday paradoxon" into account.  Chances for a clash with
> >> "someone else in the room" are actually much higher than the chance
> >> for a clash with "a *specific* number out of the ame pool".
> >
> >
> >
> >   The general solution of
> >   the probability of a collision after d draws from n possible values
> >   is given by:
> >
> >      P = 1 - ((n!) / ((n**d)((n-d)!)))
> >
> >   Given that the value for n is 2.199,023,255,552, then the objective
> >   is to find the lowest value of d for which P is greater than or equal
> >   to 0.5. In this case the value for d  is some 1.24 million.
>
>That formula does apply under the assumption(s) that the draws
>will be evenly distributed across the value space, correct?


Yes, thats correct.

    Geoff