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Network Working Group J. Klensin Request for Comments: 4897 BCP: 97 S. Hartman Updates: 3967 MIT Category: Best Current Practice June 2007

     Handling Normative References to Standards-Track Documents

Status of This Memo

 This document specifies an Internet Best Current Practices for the
 Internet Community, and requests discussion and suggestions for
 improvements.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (C) The IETF Trust (2007).


 The Internet Engineering Task Force (IETF) and Request for Comments
 (RFC) Editor have a long-standing rule that a document at a given
 maturity level cannot be published until all of the documents that it
 references as normative are at that maturity level or higher.  This
 rule has sometimes resulted in very long publication delays for
 documents and some claims that it was a major obstruction to
 advancing documents in maturity level.  The IETF agreed on a way to
 bypass this rule with RFC 3967.  This document describes a simpler
 procedure for downward references to Standards-Track and Best Current
 Practice (BCP) documents, namely "note and move on".  The procedure
 in RFC 3967 still applies for downward references to other classes of
 documents.  In both cases, annotations should be added to such

Klensin & Hartman Best Current Practice [Page 1] RFC 4897 Normative References June 2007

Table of Contents

1. Introduction …………………………………………….2 2. Terminology ……………………………………………..3 3. Normative Reference Rule ………………………………….3

 3.1. Source Documents Not Yet Processed by the IESG .............3
 3.2. Documents Already in the RFC Editor Queue ..................4

4. Target Documents Not on the Standards Track …………………4 5. Target Documents that Can Be Referenced This Way …………….4 6. Security Considerations …………………………………..5 7. Acknowledgements …………………………………………5 8. Normative References ……………………………………..5

1. Introduction

 The IETF and RFC Editor have a long-standing rule (see, e.g., RFC
 2026, Section 4.2.4 [RFC2026] and the extended discussion in RFC 3967
 [RFC3967]) that a document at a given maturity level cannot be
 published until all of the documents to which it makes a normative
 reference are at that maturity level or higher.  This rule has
 sometimes resulted in very long publication delays for documents and
 some claims that it was a major obstruction to advancing documents in
 maturity level.  Recognizing the problems that this rule sometimes
 caused, RFC 3967 established an exception procedure for normative
 downward references under some specific circumstances.  Perhaps
 because of its fairly stringent requirements, RFC 3967 has not proven
 adequate either to clear the backlog of documents awaiting upgraded
 documents or to prevent additional documents from joining that queue.
 This document replaces the long-standing rule for downward references
 to Standards-Track documents (including BCPs) that are already
 published.  For normative references to Standards-Track and BCP
 documents, that rule was to hold the newer, referencing, document
 until the referenced ones could be brought to the appropriate
 maturity level.  It is now possible, following procedures described
 below, to simply note the downward normative reference and move on.
 This document also updates RFC 3967.  When downward references from a
 source document are approved under the procedure specified in that
 specification, we recommend that the references in the approved
 (source) document be annotated in the same way as references approved
 under this rule.

Klensin & Hartman Best Current Practice [Page 2] RFC 4897 Normative References June 2007

2. Terminology

 A reference involves two documents, the one in which the reference is
 embedded and the document referenced.  Where needed for clarity,
 these documents are referred to as the "source document" and "target
 document", respectively.
 The term "Standards-Track document", as used in this specification,
 is assumed to include BCPs but not Informational or Experimental
 documents of any variety or origin.

3. Normative Reference Rule

 This document specifies an alternative to holding source documents
 until all target documents referenced normatively are upgraded or by
 applying the procedure of RFC 3967.

3.1. Source Documents Not Yet Processed by the IESG

 An author or editor who requires a normative downward reference to a
 Standards-Track RFC uses the following very simple procedure:
 o  The reference text (i.e., in the "Normative References" section of
    the source document) is written as usual.
 o  A note is included in the reference text that indicates that the
    reference is to a target document of a lower maturity level, that
    some caution should be used since it may be less stable than the
    document from which it is being referenced, and, optionally,
    explaining why the downward reference is appropriate.
 The Internet Engineering Steering Group (IESG) may, at its
 discretion, specify the exact text to be used, establish procedures
 regarding the text to use, or give guidance on this text.  When
 establishing procedures, the IESG should seek appropriate community
 These annotations are part of the source document.  If members of the
 community consider either the downward reference or the annotation
 text to be inappropriate, those issues can be raised at any time
 during the document life cycle, just as with any other text in the
 document.  There is no separate review of these references.
 With appropriate community review, the IESG may establish procedures
 for when normative downward references should delay a document and
 when downward references should be noted.  Absent specific guidance,
 authors and reviewers should use their best judgment.  It is assumed
 that, in a significant majority of cases, noting a downward reference
 is preferable to delaying publication.

Klensin & Hartman Best Current Practice [Page 3] RFC 4897 Normative References June 2007

 At the option of the author, similar notes may be attached to non-
 normative references.

3.2. Documents Already in the RFC Editor Queue

 The IESG may, at its discretion, specify a procedure to be applied to
 source documents that are already in the RFC Editor queue, awaiting
 target referenced documents.  The IESG should encourage authors with
 documents in the RFC Editor queue awaiting downward references to
 Standards-Track RFCs to evaluate whether this new rule is appropriate
 for their documents.  If authors believe that adding an annotation
 and releasing the document is the best way forward, then the IESG
 should ensure that appropriate review is conducted and, if that
 review agrees with that of the authors' evaluation, allow the
 annotations to be added.  The IESG will announce its decision via the
 normal Protocol-Action or Document-Action mechanisms.

4. Target Documents Not on the Standards Track

 In the case of a normative reference to a document not on the
 standards track that is approved under the procedures defined in RFC
 3967, the annotation described in Section 3.1 or the retrospective
 annotation described in Section 3.2, SHOULD be added to the reference
 unless the IESG, after consideration of Last Call input, concludes it
 is inappropriate.

5. Target Documents that Can Be Referenced This Way

 The "downward reference by annotation" model specified here is
 applicable only to published Standards-Track RFCs at lower maturity
 Obviously, such downward references are part of the relevant source
 document at IETF Last Call and subject to comments from the
 Advancing documents, when appropriate, is still considered preferable
 to the use of either this procedure or the one specified in RFC 3967.
 This specification does not impose a specific test or requirement to
 determine appropriateness.  This is partially because it would be
 impossible to do so for the general case, but more so because the
 intention is to permit the IESG and the community to balance the
 importance of getting a source document published against the time
 and difficulty associated with upgrading a target document.  That
 requirement is intended to be less stringent than the one of RFC

Klensin & Hartman Best Current Practice [Page 4] RFC 4897 Normative References June 2007

6. Security Considerations

 This document specifies an IETF procedure.  It is not believed to
 raise any security issues although, in principle, relaxing the
 normative downward reference rules for references associated with
 security mechanisms could make a specification less stable and hence
 less secure.

7. Acknowledgements

 This proposal was suggested by a comment by Spencer Dawkins and many
 complaints about the negative impact of the current rules.  The
 author is unsure about the validity of some of those complaints; the
 proposal is, in part, a way to test the validity question.  Spencer
 also provided helpful comments on a preliminary version.  It was
 revised in response to extensive discussion in the IESG and benefited
 significantly by comments from Brian Carpenter.

8. Normative References

 [RFC2026]  Bradner, S., "The Internet Standards Process -- Revision
            3", BCP 9, RFC 2026, October 1996.
 [RFC3967]  Bush, R. and T. Narten, "Clarifying when Standards Track
            Documents may Refer Normatively to Documents at a Lower
            Level", BCP 97, RFC 3967, December 2004.

Authors' Addresses

 John C Klensin
 1770 Massachusetts Ave, #322
 Cambridge, MA  02140
 Phone: +1 617 491 5735
 Sam Hartman
 Massachusetts Institute of Technology
 77 Massachusetts Ave
 Cambridge, MA  02139

Klensin & Hartman Best Current Practice [Page 5] RFC 4897 Normative References June 2007

Full Copyright Statement

 Copyright (C) The IETF Trust (2007).
 This document is subject to the rights, licenses and restrictions
 contained in BCP 78, and except as set forth therein, the authors
 retain all their rights.
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 Internet Society.

Klensin & Hartman Best Current Practice [Page 6]

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