Re: [DNA] RE: Review of draft-krishnan-dna-simple-01.txt

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

Hi Bernard and Jin,
Bernard Aboba wrote:
>  > Multiple NSs won't correct the wrong DNA decision from RAs with
>  > disjoint prefix lists. An NS/NA based DNA decision is overruled by RA
>  > based DNA decision. Upon receiving an RA with no known prefix, a host
>  > will assume a link change even if NS/ NA exchange indicates no link
>  > change.
>  
> [BA] Why?  If a NUD exchange suceeds, the host should merely assume
> that the information it got from that particular router is still valid, 
> not that
> it has confirmed *all* the information from *all* the routers.   So if it
> assigned a still-valid address based on a particular prefix announcement,
> it need only confirm reachability to the router that sent that prefix
> announcement.  Receiving an RA with no known prefix from some other
> router is immaterial.  And of course, if that same router updates its 
> prefix list,
> then the previously cached DNA configuration information is invalidated.
>  
> As an example, if a host previously recieved an RA with no known prefix,
> and as a result got a valid address assigned via DHCPv6, it should be able
> to confirm the validity of that address based on a NUD exchange with the
> router (while doing a DHCPv6 configuration exchange in the background).

I have to admit that when we wrote the draft, we did not consider the 
precedence between the NS/NA tests and the RS/RA test. The way I see it 
today, an RA from a router containing disjoint prefixes will only 
override a positive NA confirmation from the same router and other than 
this there will be no interaction between the NS/NA tests and te RS/RA 
tests. I will give this a little more thought and come up with some text 
on this regard.

Thanks
Suresh