Re: [rfc2462bis issue 275] DAD text inconsistencies

[Francis Dupont <Francis.Dupont at enst-bretagne.fr>]

 In your previous mail you wrote:

   >    Omitting DAD altogether removes the ability to detect and correct
   >    address collisions, whereas optimizations such as Optimistic DAD
   >    mean that while there may be a short term disruption the problem
   >    will be detected and corrected.
   >    
   > => in the real world this kind of problem cannot be corrected...
   > The only thing you can do is to avoid to reproduce the same error again.
   
   That's a rather broad statement to make,
   since there may not be L2 address conflicts, and
   EUI based v6 addresses may not be used.
   
=> L2 address conflicts are very uncommon. Personally I never got one.
The usual problem is a config which is copied but not updated,
and the auto-conf does not save you because it is not used for every nodes.

   What really matters then is the effect on (the real)
   address owner's and configuring node's applications.
   
=> usually both the real owner and the offender are dead. Murphy's law
makes the real owner an important server.

   I think it's worth getting implementors' experience
   with address conflicts with DAD, without DAD and with
   optimizations.
   
=> I am an implementor and from time to time a network manager so
I can say that:
 - address duplications happen
 - at least once DAD saved us from real trouble even the IPv6 network
   was very small at this time
So I really believe in the DAD usefulness and if you'd like to remove
or "optimize" DAD on one of my networks my answer will be "NO!".

Regards

Francis.Dupont@enst-bretagne.fr

   > PS: optimistic DAD is like optimistic russian roulette: look at in the
   > chamber after to check it is empty.
   
   That's highly emotive talk which doesn't help the discussion.
   
=> the optimistic DAD is an old topic now and I believe some of us don't
(didn't? :-) understand our opinion about it.

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