Re: I-D Action: draft-leiba-rfc2119-update-00.txt

Brian E Carpenter <> Tue, 09 August 2016 22:44 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id B6E0012D5A0 for <>; Tue, 9 Aug 2016 15:44:17 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.7
X-Spam-Status: No, score=-2.7 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id ftlRZZylUQ8C for <>; Tue, 9 Aug 2016 15:44:16 -0700 (PDT)
Received: from ( [IPv6:2607:f8b0:400e:c03::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id E6F8D12D135 for <>; Tue, 9 Aug 2016 15:44:15 -0700 (PDT)
Received: by with SMTP id pp5so9219679pac.3 for <>; Tue, 09 Aug 2016 15:44:15 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20120113; h=subject:references:from:organization:to:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding; bh=yH13soMKiIaqD/cB8lm34c6j5TCaNqsWXaL3LSjzF+4=; b=RExlPC5+o4aRtquhfmDDY7yQaESBHBZ3KfggsWlMsqz2SYKPPlzfM1I5+gy9zxBk2R N1A6Ek8TMKAd1kRX3hy35rVgknoGQ5Dlw0jA5xFOy6p8GlCjcYHvqCv4ypwbkB4M20AP LBnCpc1HsG2MOAl/6a+Hf7ipFJKA/AHegRmcLeffhhhU2z7RT+0WkyI3rhwvkLn6j/vO RZ0UOSFYQZPb8L0BpO/9yF1LLdXUXhw4irqCZJWm8VmHHjVUxymTgrWMdCVPqTvYdK/J GpffNcZK6YgOkbixYRvhB3neUR3vWf0Nbu+VQCuSKtY35SkvghsQFomYqqtJAbKz3Wbd ORxg==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20130820; h=x-gm-message-state:subject:references:from:organization:to :message-id:date:user-agent:mime-version:in-reply-to :content-transfer-encoding; bh=yH13soMKiIaqD/cB8lm34c6j5TCaNqsWXaL3LSjzF+4=; b=eguS9Spx6IEYcz5Zu6iPCugQ2tH2V3EyOMy4fa7rlpjR0RqXCYE5NI6fBIFywSk05O oAGlpdw72r1wrYTcvrVLANGac0YhXJU87CdlZBniDGJ1vwWsD/L+KvqW80Jd8VWap5d0 o5+cWRruwUf6BpdkOcXA4BeAW83UmOPGZ0Z+iPO8lPYibW/zhR08WSLXDM6nArrsG0vV onzvPZCWH9nQ8Uy/ryDV8hiihJcmt3b6UCn4AF0z7ehmRkhv7x1mwqy7X/SV5KDerzpa jhsBPmO/L7lEqrnZdVsDX8nDS99jue6xO4mu/u8MMLEbzkrwDqcsBciI4qewxOxOZS1e 5P3Q==
X-Gm-Message-State: AEkoousTrLwB02CtverkEl6aZyYhUvOqZrg0toDOLS0BX9PxxNZoJCrlWhyBEUpDNuWxFQ==
X-Received: by with SMTP id j10mr1405929pax.60.1470782653596; Tue, 09 Aug 2016 15:44:13 -0700 (PDT)
Received: from ?IPv6:2001:df0:0:2006:c0da:ac17:5f6d:8e76? ([2001:df0:0:2006:c0da:ac17:5f6d:8e76]) by with ESMTPSA id ty6sm58513572pac.18.2016. for <> (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Aug 2016 15:44:12 -0700 (PDT)
Subject: Re: I-D Action: draft-leiba-rfc2119-update-00.txt
References: <>
From: Brian E Carpenter <>
Organization: University of Auckland
To: IETF discussion list <>
Message-ID: <>
Date: Wed, 10 Aug 2016 10:44:13 +1200
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Archived-At: <>
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: IETF-Discussion <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 09 Aug 2016 22:44:18 -0000


>    o  When these words are not capitalized, they have their normal
>       English meanings; this document has nothing to do with them.

There are, and probably always will be, standards track documents
that do not cite RFC 2119 and do not use upper-case normative
keywords. In those documents, we will find usage of 'should' and
'should not' whose interpretation will remain ambiguous. (Does
'should' mean 'must unless there is a very good reason' or something
less?) I think that ambiguity is worth pointing out. I don't think
'must' and 'may' are ambiguous in that way.

However, that point leads me to another issue:

>    Authors who follow these guidelines should incorporate this phrase
>    near the beginning of their document:

I think that 'should' needs to be 'must'. Otherwise we could in theory
have documents using both 'MUST' and 'must' with no disambiguation.
(This is also a bug in RFC 2119.)

>    To reduce the number of reserved key words, the following key words
>    are deprecated, and no longer have special meanings defined by BCP
>    14:

I will be glad to see the back of SHALL, but I object to deprecating
the adjectives. They are useful - indeed, sometimes required - for
the construction of readable sentences and, for example, tables of

   Brian Carpenter

On 10/08/2016 07:55, wrote:
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>         Title           : Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words
>         Author          : Barry Leiba
> 	Filename        : draft-leiba-rfc2119-update-00.txt
> 	Pages           : 4
> 	Date            : 2016-08-09
> 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.
> The IETF datatracker status page for this draft is:
> There's also a htmlized version available at:
> Please note that it may take a couple of minutes from the time of submission
> until the htmlized version and diff are available at
> Internet-Drafts are also available by anonymous FTP at:
> _______________________________________________
> I-D-Announce mailing list
> Internet-Draft directories:
> or