RE: dns discovery for agenda? [Re: chairs and charter]

["BELOEIL Luc FTRD/DMI/CAE" <luc.beloeil@rd.francetelecom.com>]

Hi all, 

> De : Erik Nordmark [mailto:Erik.Nordmark@Sun.COM]
> 
> 
> > If we have statefull address autoconfig & stateful address 
> autoconfig, I
> > think having an additional mechanism for getting DNS server 
> addresses is not
> > a  bad thing.  At the transport layer, we have UDP, 
> UDP-lite, DCCP, TCP,
> > SCTP ... to transfer packets.  Having multiple ways to do 
> something is a
> > reasonable solution.
> 
> Two issues with multiple methods to configure the same thing that
> hasn't been brought up are:
>  - potential impact on time to discover
> 	Since each router advertisement doesn't need to contain all
> 	options will a host need to listen for RAs for some time
> 	before it decides it to DHCPv6 to find the info?

I agree, that is a generic issue when several mechanisms exist. You
could also mentioned "will a host need to wait for DHCPv6 failure before
it decides to uses well-known DNS resolver addresses" .

>  - conflicting information
> 	A host might use DHCPv6 for other reasons/other information.
> 	What should it do if the RAs and the DHCPv6 reply contains
> 	different DNS information?

Maybe should we require some architectural constraints to avoid such
scenarios? Nevertheless in multihoming scenarios that remains a critical
point.

> 	What if different RAs received on the same interface contain
> 	different DNS information?
> 

For that last point, IMHO, DNS information transported in a RA should be
associated to the prefix annouced in that RA. If several RA advertise
several prefixes with different DNS information it's a matter of policy
management on the host. Am I wrong ?


Luc 

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