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

[Ole Troan <[e-mail]>]

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.

> 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.

cheers,
Ole