Internet DRAFT - draft-leiba-rfc2119-update
draft-leiba-rfc2119-update
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
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This Internet-Draft will expire on September 08, 2017.
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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 Some Notes for Reviewers (not for publication)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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