Re: 6MAN WG Adoption call : draft-jeong-6man-rdnss-rfc6106-bis

Hi Ole,

On 22 July 2015 at 17:36, Ole Troan <otroan@employees.org> wrote:
> Mark,
>
>> My comments below in part on this draft and Fernando's earlier one seem to have been ignored again.
>
> it wasn’t our intention to ignore your comments. I don’t see them as blocking for adoption, and we wanted that done first.

Ok. It is only that I've posted them a couple of times over the last
few months (once in feedback to Fernando's ID, once to this one) and
nothing in the draft seemed to have changed.

>
>> The advice to consider RDNSS and DNSSL option values to be invalid if RA lifetime has expired is inconsistent with RFC4861's advice on the use of Router Lifetimes. A RA Lifetime of zero is valid, and should not cause options within the RA to be considered invalid - that is why they have their on lifetime values. Again quoting from RFC4861,
>>
>> "The Router Lifetime applies only to
>>                     the router's usefulness as a default router; it
>>                     does not apply to information contained in other
>>                     message fields or options. "
>>
>> For example, RDNSS addresses could be link-local addresses, so the expiry of the default router information (specifically and only indicated by the Router Lifetime) would not impact the ability to use the on-link DNS resolvers. NUD and/or the DNS resolver's failure detection methods would determine if link-local addressed resolvers are still valid to send requests to.
>
> let me try to answer the point on lifetime first.
> I’m a little confused why you say the RDNSS lifetime is tied to the Router Lifetime, that certainly wasn’t the intention.
>
> the RDNSS Lifetime text is:
>                    The value of Lifetime SHOULD by
>                    default be at least 3 * MaxRtrAdvInterval where
>                    MaxRtrAdvInterval is the Maximum RA Interval defined
>                    in [RFC4861].  A value of all one bits (0xffffffff)
>                    represents infinity.  A value of zero means that the
>                    RDNSS address MUST no longer be used.
>
> the text states that the should be larger than lifetime > 3 RA advertisement interval.
> that’s to ensure that a network that runs with very short lifetimes would survive even if a few RAs are lost.
> that’s independent of those RAs having Router Lifetime of 0.
>

Here's the text that says Router Lifetime is a constraint on the
use/validity of the RDNSS and DNSSL option values:

"Note:  An RDNSS address or a DNSSL domain name MUST be used only as
      long as both the RA router Lifetime (advertised by a Router
      Advertisement message [RFC4861]) and the corresponding option
      Lifetime have not expired."

Regards,
Mark.

> cheers,
> Ole
>
>
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