Hi - > From: "Murray S. Kucherawy" <m...@cloudmark.com> > To: "IETF discussion list" <ietf@ietf.org> > Sent: Wednesday, August 31, 2011 11:00 AM > Subject: RE: 2119bis > > > -----Original Message----- > > From: ietf-boun...@ietf.org [mailto:ietf-boun...@ietf.org] On Behalf Of > > Hector > > Sent: Wednesday, August 31, 2011 10:57 AM > > Cc: IETF discussion list > > Subject: Re: 2119bis > > > > > But I don't think there's anything wrong with the definitions as we have > > > them; > > > I think they've served us well for the last fourteen years. > > > > Correct and by far, most deployments have use SHOULD = OPTION with an > > documented right to IGNORE - so be it written so be it followed. > > This sentence is self-contradictory. "SHOULD" is, by definition, not > "OPTIONAL".
I disagree with the claim that there is a contradiction there, but I also think "IGNORE" is incorrect. The only difference between "SHOULD" and "MAY" is that the implementor / deployer needs a good excuse to not implement / employ a "SHOULD." That's not the same as "IGNORE". However, looking at an implementation from a conformance testing perspective, these are indistinguishable. If the conditions under which the feature may be omitted are well-defined, then an "if not x MUST y" structure would be much more appropriate, and this can be easily handled with the existing keywords. Randy _______________________________________________ Ietf mailing list Ietf@ietf.org https://www.ietf.org/mailman/listinfo/ietf
