Internet Engineering Task Force (IETF) B. Leiba
Request for Comments: 8174 Huawei Technologies
BCP: 14 May 2017
Updates: 2119
Category: Best Current Practice
ISSN: 2070-1721
Internet Engineering Task Force (IETF) B. Leiba
Request for Comments: 8174 Huawei Technologies
BCP: 14 May 2017
Updates: 2119
Category: Best Current Practice
ISSN: 2070-1721
Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words
RFC2119关键词中大小写的歧义性
Abstract
摘要
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.
RFC 2119指定协议规范中可能使用的公共关键字。本文件旨在通过澄清只有大写的关键词才具有定义的特殊含义来减少歧义。
Status of This Memo
关于下段备忘
This memo documents an Internet Best Current Practice.
本备忘录记录了互联网最佳实践。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on BCPs is available in Section 2 of RFC 7841.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。有关BCP的更多信息，请参见RFC 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc8174.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问http://www.rfc-editor.org/info/rfc8174.
Copyright Notice
版权公告
Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2017 IETF信托基金和确定为文件作者的人员。版权所有。
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.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(http://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Clarifying Capitalization of Key Words . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. Normative References . . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Clarifying Capitalization of Key Words . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. Normative References . . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
RFC 2119 specifies common key words, such as "MUST", "SHOULD", and "MAY", that may be used in protocol specifications. It says that the key words "are often capitalized," which has caused confusion about how to interpret non-capitalized words such as "must" and "should".
RFC2119规定了协议规范中可能使用的常用关键字，如“必须”、“应该”和“可能”。它说，关键词“通常是大写的”，这导致了人们对如何解释“必须”和“应该”等非大写单词的困惑。
This document updates RFC 2119 by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document is part of BCP 14.
本文件更新了RFC 2119，澄清了只有大写的关键词才具有定义的特殊含义。本文件是BCP 14的一部分。
The following change is made to [RFC2119]:
对[RFC2119]进行了以下更改：
=== 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:
===旧===在许多标准跟踪文档中，几个词用于表示规范中的需求。这些词通常大写。本文件定义了IETF文件中应解释的词语。遵循这些指导原则的作者应在其文件开头加入以下短语：
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.
本文件中的关键词“必须”、“不得”、“要求”、“应”、“不得”、“应”、“不应”、“建议”、“可”和“可选”应按照RFC 2119中的说明进行解释。
=== 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. These 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.
===新===在许多IETF文档中，几个单词（如下图所示）用以表示规范中的要求。这些大写的单词可以为文档带来显著的清晰度和一致性，因为它们的含义定义良好。本文件定义了IETF文件中所有大写字母的词语的解释方式。
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 这些词可以按照这里的定义使用，但不需要使用它们。具体而言，规范性文本不需要使用这些关键词。它们用于清晰和一致性，但很多规范性文本不使用它们，仍然是规范性的。
o The words have the meanings specified herein only when they are in all capitals.
o 这些词语只有在全部大写时才具有本文规定的含义。
o When these words are not capitalized, they have their normal English meanings and are not affected by this document.
o 如果这些词未大写，则它们具有正常的英语含义，不受本文件的影响。
Authors who follow these guidelines should incorporate this phrase near the beginning of their document:
遵循这些指导原则的作者应在其文件开头加入以下短语：
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] [RFC8174] when, and only when, they appear in all capitals, as shown here.
本文件中的关键词“必须”、“不得”、“必需”、“应”、“不应”、“建议”、“不建议”、“可”和“可选”在所有大写字母出现时（如图所示）应按照BCP 14[RFC2119][RFC8174]所述进行解释。
=== END ===
=== END ===
This document does not require any IANA actions.
本文件不要求IANA采取任何行动。
This document is purely procedural; there are no related security considerations.
这份文件纯粹是程序性的；没有相关的安全考虑。
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>.
[RFC2119]Bradner，S.，“RFC中用于表示需求水平的关键词”，BCP 14，RFC 2119，DOI 10.17487/RFC2119，1997年3月<http://www.rfc-editor.org/info/rfc2119>.
Author's Address
作者地址
Barry Leiba Huawei Technologies
巴里·雷巴华为技术有限公司
Phone: +1 646 827 0648
Email: barryleiba@computer.org
URI: http://internetmessagingtechnology.org/
Phone: +1 646 827 0648
Email: barryleiba@computer.org
URI: http://internetmessagingtechnology.org/