On Thu, Oct 17, 2002 at 12:54:34PM +0300, Pekka Savola wrote:
> 
>    Optimistic DAD is a useful optimization because DAD is far more 
>    likely to succeed than fail, by a factor of at least 10,000,000,000
>    to one[SOTO].  This makes it worth a little disruption in the failure
>    case to provide faster handovers in the successful case, as long as
>    the disruption is recoverable.
> 
> ==> this is totally, and completely wrong.  [SOTO] only provide analysis 
> in *some* cases, in particular autoconfigured vs privacy addresses.

I see what you mean. I need to make it clear that [SOTO] and I are
referring to strongly random addresses ... this is a requirement
for my Optimistic DAD draft anyway for exactly this reason.

Do you this it is fair to say:

   DAD is far more likely to succeed than fail FOR RANDOMLY
   AUTOCONFIGURED ADDRESSES, by a factor of at least 10,000,000,000
   to one[SOTO].

Do you think it would be advisable for me to add:

   Optimistic DAD MUST NOT be used for manually configured addresses

... because as you point out, manually configured addresses are
far more likely to fail and being a MobileIP type I'm mainly 
interested in configuring CoAs anyway.

> For manually assigned addresses, I believe the ratio is closer
> to 1:10 or 1:100 (unmeasurable, of course).

I'd be really interested to know if anyone has any indicative
figures on MAC address collision: it is inevitable that somewhere
out there there are two adaptors with the same MAC address due
to human frailties, but how many?

Thanks for your feedback!

-----Nick
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