Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words
draft-leiba-rfc2119-update-00
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Author | Barry Leiba | ||
| Last updated | 2016-08-09 | ||
| Stream | (None) | ||
| Formats | plain text xml htmlized pdfized bibtex | ||
| Reviews |
SECDIR Last Call review
(of
-01)
Has Nits
|
||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-leiba-rfc2119-update-00
Network Working Group B. Leiba
Internet-Draft Huawei Technologies
Updates: 2119 (if approved) August 09, 2016
Intended status: Best Current Practice
Expires: February 08, 2017
Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words
draft-leiba-rfc2119-update-00
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, and by deprecating some versions of the key
words.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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 February 08, 2017.
Copyright Notice
Copyright (c) 2016 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
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 to this document. Code Components
extracted from this document must 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.
1. Introduction
Leiba Expires February 08, 2017 [Page 1]
Internet-Draft RFC 2119 Clarification August 2016
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. It also
reduces wording conflicts by deprecating some synonymous key words.
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. That said, it may still be worth continuing
the discussion a bit.
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:
Leiba Expires February 08, 2017 [Page 2]
Internet-Draft RFC 2119 Clarification August 2016
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 standards track documents several words are used to signify
the requirements in the specification. These words are often
capitalized, as shown below, but they do not have to be. This
document defines how these words are interpreted in IETF documents
when the words are capitalized.
o These words can be used as defined here, but it is not required
that they be. 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 does not need to use them.
o The words have the meanings specified herein only when they are
capitalized.
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", "SHOULD", "SHOULD NOT", and
"MAY" in this document are to be interpreted as described in
BCP 14 [RFC2119],[RFCxxxx] when, and only when, they appear
capitalized, as shown.
=== END ===
[[RFC Editor: Please replace "RFCxxxx", above, with a reference to
this RFC number, and remove this note.]]
3. Deprecating some synonymous key words
To reduce the number of reserved key words, the following key words
are deprecated, and no longer have special meanings defined by BCP
14:
REQUIRED, SHALL, SHALL NOT, RECOMMENDED, NOT RECOMMENDED, OPTIONAL
4. IANA Considerations
There are no IANA considerations for this document.
5. Security Considerations
Leiba Expires February 08, 2017 [Page 3]
Internet-Draft RFC 2119 Clarification August 2016
This document is purely procedural, and there are no related security
considerations.
6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Author's Address
Barry Leiba
Huawei Technologies
Phone: +1 646 827 0648
Email: barryleiba@computer.org
URI: http://internetmessagingtechnology.org/
Leiba Expires February 08, 2017 [Page 4]