Updating When Standards Track Documents May Refer Normatively to Documents at a Lower Level

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 ): 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 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.

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.

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.