Re: [core] Robert Wilton's Discuss on draft-ietf-core-sid-16: (with DISCUSS and COMMENT)

Michael Richardson <mcr+ietf@sandelman.ca> Tue, 13 July 2021 17:38 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Robert Wilton <rwilton@cisco.com>, "The IESG" <iesg@ietf.org>, draft-ietf-core-sid@ietf.org, core-chairs@ietf.org, core@ietf.org
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Date: Tue, 13 Jul 2021 13:38:33 -0400
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Subject: Re: [core] Robert Wilton's Discuss on draft-ietf-core-sid-16: (with DISCUSS and COMMENT)
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Robert Wilton via Datatracker <noreply@ietf.org> wrote:
    > (1) I would like further discussion regarding whether SIDs are bound just to
    > the schema name, or the schema item definition.

I'm not sure I understand the question.... I guess schema name is the leaf definition.

    > The draft states that if the
    > definition is changed in a non-backwards-compatible (NBC) way then a new SID
    > SHOULD be allocated.

True, I assume that this leads to a new YANG leaf name.

    > But I don't understand how this will work.  Given that
    > the .sid file would then contain exactly the same path but with different sids
    > assigned (for every time the meaning of the definition changes), then how do
    > consumers of the sid file know which sid to use for a given path (given that
    > there is no indication in the .sid file)?  Instead, I think that this is the
    > wrong way to be handling NBC changes, and SIDs should be bound only to the
    > schema path (i.e., the name of the item), and a new SID is only allocated if
    > the name/path changes, and otherwise the same SID is used, even if the
    > definition changes in a non-backwards-compatible way.

This is my understanding.

    > (3) This draft makes use of the rc:yang-data extension.  Was there any
    > discussion about using "YANG Data Structure Extensions" (RFC 8791) instead,
    > which is meant to be a cleaner formulation of the rc:yang-data extension, and
    > without the dependency on RESTCONF?  I would suggest that using RFC 8791 would
    > be preferable if possible.

I don't know of any such discussion, but I don't really understand the distinction.

    > (4) The policy in 7.4.2 for allocation a SID mega-range seems to aiming this
    > towards organizations rather than individuals.

Yes, the idea being that "Zigbee" or "IEEE" or ... would allocate a mega-range.

    > The policy in 7.6 for the "IETF
    > YANG SID Registry" requires an RFC.  What is the mechanism if an individual or
    > open source project wanted to get SIDs assigned for some of their YANG modules?

    > I.e., should we be defining a separate mega-range, managed by IANA, with just
    > Expert Review or Specification Required so that these modules could use SIDs
    > allocated?  Or do you envisage a separate entity taking up the responsibility
    > for coordinating this?

My impression was that there would be a mega-range operated outside of IANA
for this (open source, non-RFC YANG module) kind of thing, but I think that
the energy for doing that may have waned.

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