Re: [DNA] Some questions about Simple DNA

[Suresh Krishnan <suresh.krishnan@ericsson.com>]

Hi Bernard,

Bernard Aboba wrote:
>  > * Address was configured using SLAAC : Nobody is keeping track of the
>  > address used by the node. In this case when the node gets back into the
>  > link, it needs to do DAD.
>  >
>  > Is this an acceptable bifurcation?
> 
> Not completely.  If the host is only gone from the link for a small 
> period (e.g. enough to complete a handoff), then I don't see why DAD 
> should be required, since enough time would not have elapsed to allow 
> another host to complete DAD for the same address.

In order to do this we need to keep track of how long the host has been 
gone from the link. And since the DAD transmits and timeouts are based 
on host specific configuration, it might be very hard to come up with a 
decent borderline number on the amount of time elapsed away from the 
link when the host needs to start doing DAD.

>  
> Also, longer absences are similar in the effect of network partitioning 
> and healing, where two hosts can each complete DAD, and therefore come 
> to believe that their addresses are unique.  Yet when their previously 
> partiioned networks are joined, they can discover conflicts.  Therefore 
> the problem of ongoing conflict detection exists in either scenario.

Agree.

Thanks
Suresh