Internet Engineering Task Force (IETF)
Request for Comments: 8067
BCP: 97
Updates: 3967
Category: Best Current Practice
ISSN: 2070-1721
B. Leiba
Huawei Technologies
January 2017

Updating When Standards Track Documents May Refer Normatively to

Documents at a Lower Level


RFC 3967 specifies a process for allowing normative references to documents at lower maturity levels ("downrefs"), which involves calling out the downref explicitly in the Last Call notice. That requirement has proven to be unnecessarily strict, and this document updates RFC 3967, allowing the IESG more flexibility in accepting downrefs in Standards Track documents.

Status of This Memo

This memo documents an Internet Best Current Practice.

This document is a product of the Internet Engineering Task Force (IETF). It has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on BCPs is available in Section 2 of RFC 7841.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at

Copyright Notice

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This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents ( 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  The IESG's Responsibility with Respect to Downrefs  . . . . .   2
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   4.  Normative References  . . . . . . . . . . . . . . . . . . . .   3
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   3

1. Introduction

[RFC3967] notes the importance of assuring that normative references from Standards Track and Best Current Practice (BCP) documents are appropriately mature, and specifies a process for allowing normative references to documents at lower maturity levels ("downrefs"). That process starts at IETF Last Call (see Section 3 of [RFC3967]):

For Standards Track or BCP documents requiring normative reference to documents of lower maturity, the normal IETF Last Call procedure will be issued, with the need for the downward reference explicitly documented in the Last Call itself. Any community comments on the appropriateness of downward references will be considered by the IESG as part of its deliberations.

Section 2 of [RFC3967] lists some conditions under which downrefs may make sense. In addition to those, it has become common for working groups to produce foundational documents (which contain important information such as terminology definitions and architectural design and considerations) at Informational status, and those documents are often needed as normative references in the Standards Track protocol documents that follow.

The requirement to explicitly mention the downrefs and the need for them in the Last Call message has proven to be unnecessarily restrictive and has often resulted in unnecessary repetitions of Last Call, with the corresponding delay and with no real benefit.

2. The IESG's Responsibility with Respect to Downrefs

The process in RFC 3967 is hereby updated to specify that explicitly documenting the downward references in the Last Call message is strongly recommended but not required. The responsible AD should still check for downrefs before sending out the Last Call notice, but if an undetected downref is noticed during Last Call or IESG review, any need to repeat the Last Call is at the discretion of the IESG. However, the process in RFC 3967 is not fundamentally altered: If the IESG decides not to repeat the Last Call, the status of the affected downrefs is not changed, and the process in RFC 3967 will still apply if those downrefs are used in the future.

This gives the IESG the responsibility to determine the actual maturity level of the downward reference with respect to the document at hand, and to decide whether or not it is necessary to explicitly ask the IETF community for comments on the downref on a case-by-case basis. In making that decision, the IESG should take into account the general discussion in RFC 3967. The responsible AD should make sure that the omission is recorded as a comment in the datatracker.

3. Security Considerations

Referencing immature protocols can have security and stability implications, and the IESG should take that into account when deciding whether re-consulting the community is useful.

4. Normative References

   [RFC3967]  Bush, R. and T. Narten, "Clarifying when Standards Track
              Documents may Refer Normatively to Documents at a Lower
              Level", BCP 97, RFC 3967, DOI 10.17487/RFC3967, December
              2004, <>.

Author's Address

Barry Leiba
Huawei Technologies

   Phone: +1 646 827 0648