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Versions: 00 01 02 RFC 8174

Network Working Group                                           B. Leiba
Internet-Draft                                       Huawei Technologies
Updates: 2119 (if approved)                               March 09, 2017
Intended status: Best Current Practice
Expires: September 08, 2017

       Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words
                     draft-leiba-rfc2119-update-02

Abstract

   RFC 2119 specifies common key words that may be used in protocol
   specifications.  This document aims to reduce the ambiguity by
   clarifying that only UPPERCASE usage of the key words have the
   defined special meanings.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 08, 2017.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Simplified BSD License.

1.  Introduction





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   RFC 2119 specifies common key words, such as "MUST", "SHOULD", and
   "MAY", that may be used in protocol specifications.  It says that
   those key words "are often capitalized," and that has caused
   confusion about how to interpret non-capitalized words such as "must"
   and "should".

   This document updates RFC 2119 by clarifying that only UPPERCASE
   usage of the key words have the defined special meanings.  This
   document will become part of BCP 14 when it is approved.  [[RFC-
   Editor: Please change the previous sentence to "This document is part
   of BCP 14."]]

1.1.  Some Notes for Reviewers (not for publication)

   [[RFC-Editor: Please remove this section before publishing.]]

   This update is intentionally small and focused, and quite
   intentionally updates, but does not replace, RFC 2119.  The author
   considers it important to retain the reference to RFC 2119 because of
   the general familiarity with the number, and to phase in the use of
   "BCP 14".  Note, though, that the References section uses the RFC
   numbers, not the BCP number.  This is because is needs to be clear
   when a document has adopted this update, and the dual reference to
   RFC 2119 *and* this document gives that clarity.

   The point has been made by some that having case be significant to
   the meanings of words is unusual and may be a bad idea.  There is
   specific concern about causing confusion to readers whose native
   languages do not have a distinction between upper and lower case
   (consider Chinese and Hebrew, for example).  The author believes this
   has been discussed and addressed, and that those maintaining this
   point are in the rough.

   There have been suggestions that while we're here we should consider
   a broader BCP 14 update that also talks about proper use of the key
   words, when they should not be used, avoiding overuse, and so on.
   The author agrees, but thinks is best to keep that as a separate
   effort, as coming to consensus on such an update is likely to be much
   more difficult, and is likely to take much longer.

2.  Clarifying Capitalization of Key Words

   The following change is made to [RFC2119]:


   === OLD ===
   In many standards track documents several words are used to signify
   the requirements in the specification.  These words are often
   capitalized.  This document defines these words as they should be
   interpreted in IETF documents.  Authors who follow these guidelines
   should incorporate this phrase near the beginning of their document:



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   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.


   === NEW ===
   In many IETF documents several words, when they are in all capitals
   as shown below, are used to signify the requirements in the
   specification.  Those capitalized words can bring significant clarity
   and consistency to documents because their meanings are well defined.
   This document defines how those words are interpreted in IETF
   documents when the words are in all capitals.

   o  These words can be used as defined here, but using them is not
      required.  Specifically, normative text does not require the use
      of these key words.  They are used for clarity and consistency
      when that is what's wanted, but a lot of normative text does not
      use them, and is still normative.

   o  The words have the meanings specified herein only when they are in
      all capitals.

   o  When these words are not capitalized, they have their normal
      English meanings; this document has nothing to do with them.

   Authors who follow these guidelines should incorporate this phrase
   near the beginning of their document:

      The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
      "MAY", and "OPTIONAL" in this document are to be interpreted as
      described in BCP 14 [RFC2119],[RFCxxxx] when, and only when, they
      appear in all capitals, as shown here.


   === END ===

   [[RFC Editor: Please replace "RFCxxxx", above, with a reference to
   this RFC number, and remove this note.]]

3.  IANA Considerations

   There are no IANA considerations for this document.

4.  Security Considerations

   This document is purely procedural, and there are no related security
   considerations.

5.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.


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Author's Address

   Barry Leiba
   Huawei Technologies

   Phone: +1 646 827 0648
   Email: barryleiba@computer.org
   URI:   http://internetmessagingtechnology.org/













































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