8. What to Do in "bis" Documents

On occasion, an RFC is issued that obsoletes a previous edition of the same document. We sometimes call these "bis" documents, such as when RFC 4637 is to be obsoleted by draft-ietf-foo-rfc4637bis. When the original document created registries and/or registered entries, there is a question of how to handle the IANA Considerations section in the "bis" document.

If the registrations specify the original document as a reference, those registrations should be updated to point to the current (not obsolete) documentation for those items. Usually, that will mean changing the reference to be the "bis" document.

There will, though, be times when a document updates another, but does not make it obsolete, and the definitive reference is changed for some items but not for others. Be sure that the references always point to the correct, current documentation for each item.

For example, suppose RFC 4637 registered the "BANANA" flag in the "Fruit Access Flags" registry, and the documentation for that flag is in Section 3.2.

The current registry might look, in part, like this:

Name        Description           Reference
--------    -------------------   ---------
BANANA      Flag for bananas      [RFC4637], Section 3.2

If draft-ietf-foo-rfc4637bis obsoletes RFC 4637 and, because of some rearrangement, now documents the flag in Section 4.1.2, the IANA Considerations of the bis document might contain text such as this:

IANA is asked to change the registration information for the BANANA flag in the "Fruit Access Flags" registry to the following:

Name        Description           Reference
--------    -------------------   ---------
BANANA      Flag for bananas      [[this RFC]], Section 4.2.1

In many cases, if there are a number of registered references to the original RFC and the document organization has not changed the registered section numbering much, it may simply be reasonable to do this:

Because this document obsoletes RFC 4637, IANA is asked to change all registration information that references [RFC4637] to instead reference [[this RFC]].

If information for registered items has been or is being moved to other documents, then the registration information should be changed to point to those other documents. In most cases, documentation references should not be left pointing to the obsoleted document for registries or registered items that are still in current use. For registries or registered items that are no longer in current use, it will usually make sense to leave the references pointing to the old document -- the last current reference for the obsolete items. The main point is to make sure that the reference pointers are as useful and current as is reasonable, and authors should consider that as they write the IANA Considerations for the new document. As always: do the right thing, and there is flexibility to allow for that.

It is extremely important to be clear in your instructions regarding updating references, especially in cases where some references need to be updated and others do not.