Re: [Lsr] When is an IANA Registry Required

[tom petch <[e-mail]>]

From: Lsr <[e-mail]> on behalf of Tony Li <[e-mail]>
Sent: 17 March 2021 20:56

Les,

[Les:] The question here is whether there is a qualitative difference between two classes of bit fields.

That is indeed the key question. IMHO, there is not.

I don’t much care if a field is updated by a bis document or a related document. Regardless of the cause, as soon as there is more than one source of truth about the field, we are
creating ambiguity and confusion.

At the same time, I see no point in a registry with contents that never change. Thus, I will propose an alternative: by analogy to copy-on-write shared memory semantics, I propose that
we apply ‘registry-on-write’ semantics.

Specifics: When a potentially shared field is created, the defining document speciifies the name of a future registry, but does NOT request IANA create the registry at this time. When any document wishes
to update the field, it requests that IANA create it and populate it with both legacy and updated values.

Implementors that come along either document know where the source of truth is.  If the registry has not been created, then there is no ambiguity. If it has been, then there is no ambiguity.

Thoughts?

<tp>
I keep seeing YANG modules which reference the RFC that set up the IANA Registry which by then is of course out-of-date as the Normative definition is now in the IANA Registry.  I suspect that the authors fail to notice that this is now an IANA registry just reading the body of the RFC.  We do hide IANA Considerations out of site in Section 42 or some such tucked away at the end of the document.

The other issue is that if you want an example of abysmal choice of an identifier, then the IANA Registry names provide a wealth of examples, along with a comprehensive set of examples of how not to structure information in a hierarchy (assuming, that is, that you want others to be able to find the information).

LSR is not bad in this regard, compared to some routing WG, but it could do better.  Thus I see
Sub-sub-TLV
sub-sub-TLVs
Sub-TLVs
etc
For me everyone of these is not as helpful as it could be.  What matters?  TLV 144, so that comes first; to me, it is a no-brainer but clearly my brain is different.

Tom Petch

Tony