Re: [DNSOP] Cache utilization review and suggestion for EDNS client-subnet

[Mukund Sivaraman <[e-mail]>]

Hi Yuri

On Thu, Feb 04, 2016 at 11:51:31AM +0100, Yuri Schaeffer wrote:
> In any case it would answer with A2 because given the information
> provided this is the most specific answer (it gets it from the root of
> the tree).

The draft doesn't state that the answer is for the SOURCE PREFIX-LENGTH
when SCOPE > SOURCE. At all other times, the answer is meant to be
cached at the SCOPE PREFIX-LENGTH.

I quote the draft (all that's there on the topic):

>  The SCOPE PREFIX-LENGTH in the response indicates the network for
>  which the answer is intended.
>
>  A SCOPE PREFIX-LENGTH value longer than the SOURCE PREFIX-LENGTH
>  indicates that the provided prefix length was not specific enough to
>  select the most appropriate Tailored Response.  Future queries for
>  the name within the specified network SHOULD use the longer SCOPE
>  PREFIX-LENGTH.
	       
Where does it say that the answer is for the SOURCE PREFIX-LENGTH?


> You seem to imply that a SCOPE > SOURCE means an answer from further
> down the tree. But I think it doesn't, or at least it shouldn't. The
> SCOPE is not tied to an answer but rather used as an indicator how
> many bits the authority needs/wants for the most/more specific answer.

So you are saying that your assumption is more correct than my
assumption. :) That may be so, but both are assumptions and because we
can both assume whatever we want, it would be best to describe what the
correct meaning and behavior is in the draft, wouldn't you agree?

Having the auth and resolver sides doing different things in different
flavours of implementation would lead to incorrect caching.

		Mukund