Hi Dean I agree with you which I suggested before an update to the RFC [*], I actually writing a work in progress ID, you may give me your suggestion if you like. I recommend you use for your work IF, THEN rather than MUST. Easier to read.
* http://tools.ietf.org/id/draft-baryun-rfc2119-update-00.txt AB > > > I've always held to the idea that RFC 2119 language is for defining > levels of compliance to requirements, and is best used very sparingly > (as recommended in RFC 2119 itself). To me, RFC 2119 language doesn't > make behavior normative -- rather, it describes the implications of > doing something different than the defined behavior, from "will break > the protocol if you change it" to "we have reason to think that there > might be a reason we don't want to describe here that might influence > you not to do this" to "here are some reasons that would cause you to > do something different" and on to "doing something different might > offend the sensibilities of the protocol author, but probably won't > hurt anything else." > > But I'm ghost-editing a document right now whose gen-art review > suggested replacing the vast majority of "is" "does" and "are" prose > with MUST. The comments seem to indicate that protocol-defining text > not using RFC 2119 language (specifically MUST) is "not normative". > > This makes me cringe. But my co-editor likes it a lot. And I see smart > people like Ole also echoing the though that RFC 2119 language is what > makes text normative. > > For example, the protocol under discussion uses TLS or DTLS for a > plethora of security reasons. So, every time the draft discusses > sending a response to a request, we would say "the node MUST send a > response, and this response MUST be constructed by (insert some > concatenation procedure here) and MUST be transmitted using TLS or > DTLS. > > Or, a more specific example: > > For the text: > > In order to originate a message to a given Node-ID or > Resource-ID, a node constructs an appropriate destination list. > > > The Gen-ART comment here is: > -First sentence: "a node constructs" -> "a node MUST construct" > > > We'll literally end up with hundreds of RFC 2119 invocations (mostly > MUST) in a protocol specification. > > Is this a good or bad thing? My co-editor and I disagree -- he likes > formalization of the description language, and I like the English > prose. But it raises process questions for the IETF as a whole: > > Are we deliberately evolving our language to use RFC 2119 terms as the > principle verbs of a formal specification language? > > Either way, I'd like to see some consensus. Because my head is > throbbing and I want to know if it MUST hurt, SHOULD hurst, or just > hurts. But I MUST proceed in accordance with consensus, because to do > otherwise would undermine the clarity of our entire specification > family. > > -- > Dean >
