> -----Original Message----- > From: ietf-bounces@xxxxxxxx [mailto:ietf-bounces@xxxxxxxx] 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. _______________________________________________ Ietf mailing list Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf