my feeling and belief is that RFC 2119 only gives SHOULD and RECOMMENDED the same normative requirement level, but that it does not override or change the distinct meanings of these words in English. sentences using each of these terms have different meanings in English, even when those sentences appear in RFCs. -michael thornburgh > From: ietf-bounces@xxxxxxxx [mailto:ietf-bounces@xxxxxxxx] On Behalf Of John C Klensin > Sent: Monday, June 24, 2013 5:40 AM > > --On Monday, June 24, 2013 07:52 -0400 Phillip Hallam-Baker > <hallam@xxxxxxxxx> wrote: > > > They are not synonyms > > > > Lets go back to 1980: > > > > Implementations SHOULD support DES > > vs > > RECOMMENDED encryption algorithms: DES, IDEA > > Actually, that is the point. The usage above, although much > earlier, reflects the Protocol Specification/ Applicability > Statement split rather well. > > But 2119's language makes the two terms substitutable for and > equivalent to each other, which is about as close a definition > of "synonyms" as one can find. What I said is that making them > equivalent was probably a mistake and that treating them that > was should be discouraged. Others expressed agreement with that > assessment. > > Personally, I don't think the problem is severe enough to reopen > 2119. If others disagree and believe that 2119 is generating > enough problems to be worth an update, I await a draft. > > So, other than quibbling about the "synonym" issue -- not > generally, which no one has claimed, but in context with 2119-- > are you disagreeing and, if so, about what? > > john >