Network Working Group                                          T. Hansen
Internet-Draft                                         AT&T Laboratories
Intended status: Informational                                D. Crocker
Expires: January 4, 2012                     Brandenburg InternetWorking
                                                            July 3, 2011


                     Non-Normative Synonyms in RFCs
                  draft-hansen-nonkeywords-non2119-00

Abstract

   Specifications can contain normative keywords, as defined in RFC
   2119, to signify requirements, permission or prohibitions.  They
   include MUST, SHOULD and MAY, which are commonly spelled in all
   CAPITALS (but need not be).  These words can also be used for non-
   normative purposes.  However when used within an RFC this is
   confusing, given their typical use as normative vocabulary, even when
   they do not formally have normative import.

   Several words and phrases are specified in this document for non-
   normative purposes as alternatives to the normative vocabulary of RFC
   2119.  Authors who follow these guidelines do NOT need to incorporate
   any declaration at the beginning of their document.

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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   This Internet-Draft will expire on January 4, 2012.

Copyright Notice

   Copyright (c) 2011 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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   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


.  A List of Synonyms

   To indicate a degree of requirement, permission or prohibition for an
   aspect of a specification, words such as MUST, SHOULD and MAY are
   defined as normative vocabulary in the culture of RFCs.[RFC2119].
   However it is also natural to use them non-normatively, in a
   narrative fashion.  Even when this is permitted, such as RFCs that do
   not invoke the conventions of RFC 2119, non-normative use of these
   words can be confusing; their normative meaning is too deeply
   ingrained for RFCs.

   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 [RFC2119].

   Fortunately, there are other words readily available, in lieu of the
   RFC 2119 words.



      MUST, REQUIRED, SHALL:  The words "needs to" and "necessary" can
         be used to connote that something is essential.

      SHOULD, RECOMMENDED:  The words "ought", "encouraged" and "suggest
         strongly" can be used to connote something that is strongly
         urged.

      MAY, OPTIONAL:  The words "can" and "might" can be used to
         indicate the possibility of or ability for an action.

      NOT:  The word "not" may be freely used with any of the above
         suggestions and will not be taken to have any separate 2119
         connotation.  The word only takes on a special meaning when it
         is combined with one of the RFC 2119 words.  For example,
         "ought not" is non-normative, while "should not" and "SHOULD
         NOT" are normative in the RFC 2119 sense.

   This document may be discussed on the ietf@ietf.org mailing list.



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.  Acknowledgements

   TBD


.  IANA Considerations

   This document has no IANA considerations.


.  Security Considerations

   The 2119 terms are frequently used to specify behavior with security
   implications.  The effects on security of changing something from a
   "MUST" to a "needs to", or vice versa, can be very subtle, as one has
   normative meaning and the other does not.  Document authors should
   take the time to consider the effects of using non-normative verbiage
   as specified in this document instead of the normative verbiage from
   2119.


.  Informative References

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


Authors' Addresses

   Tony Hansen
   AT&T Laboratories
   200 Laurel Ave South
   Middletown, NJ  07748
   USA

   Phone: +1.732.420.8934
   Email: tony+nonkeywords@maillennium.att.com














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   D. Crocker
   Brandenburg InternetWorking
   675 Spruce Dr.
   Sunnyvale
   USA

   Phone: +1.408.246.8253
   Email: dcrocker@bbiw.net
   URI:   http://bbiw.net










































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