Jared Mauch wrote:
we can specify that AAAA be sent as additional data for QTYPE=A, and
that A be sent as additional data when QTYPE=AAAA.
given identical deployment curves along both the ANYA and
additional-data timelines, we will get identical results.
As this is DNSOP, what implementations support this?
of authorities, none.
of recursives as initiators, most.
of recursives as responders, none.
of stubs, some.
there are two measurable lobes here. one is now, where any authority who
adopts this behaviour is likely to pre-seed the recursive initiator's
cache with "the other answer" (among A and AAAA), and any stub who makes
two queries in series (AAAA then A) will get a faster answer to the
second query.
the other is the future, where stubs are taught to notice the additional
data section and begin to avoid the second query, and where recursive
responders both ensure that they do cache additional data whose owner is
the same as the effective qname, and begin to send additional data to stubs.
so, the benefit begins immediately, but gets better over time, and there
is no new signalling required, and nothing ever breaks, and it is never
necessary to try-then-fallback (causing additional round trips.)
have no fear. every few years this topic comes up, and i say what i'm
saying, and we don't do it, and then people ask for QDCOUNT>1 again. so
we are right on track at this stage of the thread. had the response to
"resimprove" been better, i would have written this up before now.
--
P Vixie
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