-----Original Message-----
From: ietf-bounces(_at_)ietf(_dot_)org
[mailto:ietf-bounces(_at_)ietf(_dot_)org] On Behalf Of John C Klensin
Sent: Saturday, September 03, 2011 6:00 AM
To: Sam Hartman; Eric Burger
Cc: IETF discussion list
Subject: Re: 2119bis
Note that this loops back to the the discussion about
conformance and certification. The standards bodies whose
principal concerns about about conformance and certification
cannot use what we call SHOULD because one cannot build a
conformance test around a case that might have exceptions,
especially exceptions that are not completely enumerated. They
can, and do, use what we periodically describe with language
like "MUST implement but are not required to configure in
operation" (and, to add to the confusion, sometimes call that
"SHOULD use"), but the conformance test then checks only for the
implementation and, perhaps, for the presence of the knob.
We do have a few RFCs that have a subsection called "Conformance Requirements"
or something close to it. Section 3 of RFC3464 comes to mind, and it's not
that old. I take it the current posture in the IETF is that such things are
actually a bad idea, or at least not something we encourage?
For especially large or complex protocol documents, it might not be a bad idea
to have all the MUSTs, SHOULDs and MAYs enumerated in one place as a summary
for implementers to use as a checklist, and they can then consult the rest of
the document for the details about how to implement each point.
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