While we are on the topic of definitions I hoped to stimulate thinking and we can reach the conclusion that best meets our needs.
The source parent document is at the URL on the ANSI web site http://publicaa.ansi.org/sites/apdl/Documents/Standards%20Activities/International%20Standardization/ISO/ISO_IEC_Directives_Part2.pdf ISO/IEC Directives, Part 2 Rules for the structure and drafting of International Standards George T. Willingmyre, P.E. President, GTW Associates Spencerville, MD USA 20868 301.421.4138 www.gtwassociates.com ----- Original Message ----- From: Mykyta Yevstifeyev To: ietf@ietf.org Sent: Thursday, September 01, 2011 9:48 AM Subject: Re: 2119bis George, We currently use MUST in regular cases and SHALL when we either want not to create confusion where non-normative "must" is used or for aesthetic reasons, eg. to make a requirement look not so strict as MUST implies (even though formally they both have similar force). I personally use SHALL when I mean "it is to be so" and not strict "it is mandatory and obligatory and compulsory and <...> to be so". CAN and CANNOT are an interesting idea, but they have little in common with conformance. Current 2119 language, as primarily used in <http://tools.ietf.org/html/rfc1123#page-11>, was intended to clear up the requirements on support of particular feature(s). Yes, it is sometimes desired to express possibility and allowance, but IMO simple "can" and "cannot" are fine for this purpose. I don't actually think Annex H of <I don't know what since you're providing only part of it> should be referenced in 2119bis. Mykyta Yevstifeyev 01.09.2011 16:17, George Willingmyre wrote: I offer for consideration in the attachment the ISO and IEC requirements for use of the terms "Shall" ; Shall not"; "Should"; "Should not" ; "May"; "Need not" ; "Can'; "Cannot" in ISO and IEC standards. This document explains why ISO/IEC selects "Shall" and "Shall not" rather than "Must" and "Must not" to denote mandatory requirements. "Do not use "must" as an alternative for "shall". (This will avoid any confusion between the requirements of a document and external statutory obligations.)" It is in the interests of IETF to contemplate and perhaps reference this ISO/IEC document somehow in our definition of the terms below 2.1. MUST . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2. MUST NOT . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.3. SHOULD . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.4. SHOULD NOT . . . . . . . . . . . . . . . . . . . . . . . . 4 2.5. MAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 George T. Willingmyre, P.E. President, GTW Associates Spencerville, MD USA 20868 301.421.4138 www.gtwassociates.com _______________________________________________ Ietf mailing list Ietf@ietf.org https://www.ietf.org/mailman/listinfo/ietf ------------------------------------------------------------------------------ _______________________________________________ Ietf mailing list Ietf@ietf.org https://www.ietf.org/mailman/listinfo/ietf
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