Table of Contents

RFC8174 - Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words

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Table 1: Data sheet for RFC8174 Ambiguity of Uppercase vs Lowercase in RFC2119 - Key words for use in RFCs to Indicate Requirement Levels Key Words
Title Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words
Acronym
Version 2017
Document Number RFC8174
Release Date Month YYYY
Reference https://tools.ietf.org/html/rfc8174
Note: The following is an excerpt from the official IETF RFC. It is provided here as a convenience and is not authoritative. Refer to the original document as the authoritative reference.

Abstract

RFC2119 - Key words for use in RFCs to Indicate Requirement Levels 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.

Introduction

RFC2119 - Key words for use in RFCs to Indicate Requirement Levels 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”.
This document updates RFC2119 - Key words for use in RFCs to Indicate Requirement Levels by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document is part of BCP 14.