Hi Qiufang,

Thank you very much for addressing my comments and for the clarifications.
They are OK for me.

Best regards,

Ines

On Thu, Jan 8, 2026 at 9:39 AM maqiufang (A) <[email protected]> wrote:

> Hi, Ines,
>
>
>
> Thanks a lot for the careful review, the authors try to update the draft
> to incorporate your comments below, and the diff is available at:
> https://author-tools.ietf.org/diff?url_1=https://raw.githubusercontent.com/netmod-wg/system-config/refs/heads/Qiufang-1/draft-ietf-netmod-system-config-17.txt.
> Please also see my response below inline with [Qiufang]...
>
>
>
> -----Original Message-----
> From: Ines Robles via Datatracker [mailto:[email protected]]
> Sent: Wednesday, January 7, 2026 9:32 AM
> To: [email protected]
> Cc: [email protected]; [email protected];
> [email protected]
> Subject: draft-ietf-netmod-system-config-16 ietf last call Genart review
>
>
>
> Document: draft-ietf-netmod-system-config
>
> Title: System-defined Configuration
>
> Reviewer: Ines Robles
>
> Review result: Almost Ready
>
>
>
> I am the assigned Gen-ART reviewer for this draft. The General Area Review
> Team (Gen-ART) reviews all IETF documents being processed by the IESG for
> the IETF Chair.  Please treat these comments just like any other last call
> comments.
>
>
>
> For more information, please see the FAQ at
>
>
>
> <https://wiki.ietf.org/en/group/gen/GenArtFAQ>.
>
>
>
> Document: draft-ietf-netmod-system-config-16
>
> Reviewer: Ines Robles
>
> Review Date: 2026-01-06
>
> IETF LC End Date: 2026-01-06
>
> IESG Telechat date: Not scheduled for a telechat
>
>
>
> Summary:
>
>
>
> This document introduces the concept of a system configuration datastore
> holding configuration controlled by the system on which a server is running.
>
> The system configuration can be referenced by configuration explicitly
> created by clients.
>
>
>
> The document is complete and well written. I have a few questions and
> comments that would be helpful to address before publication.
>
>
>
> Comments/Questions:
>
>
>
> 1.- Section 1.1: Given that <system> is read-only to clients, how does the
> definition of “conventional configuration datastore” apply to <system>,
> particularly with respect to statements about copying data between
> datastores?
>
> Is “conventional” intended to refer primarily to shared schema structure
> rather than to support for operational behavior such as copying?
>
> [Qiufang] You are raising a good point. The current definition inherits
> the statement from 8342, which also defines <intended> (read-only
> datastore) as a conventional configuration datastore as well. This might be
> slightly misleading. But also note that a client can indeed read from
> <system> and copy that data into other conventional datastores (e.g.,
> <candidate> or <running>), while any protocol operation that attempts to
> copy data into <system> MUST fail. I am trying to add some clarification in
> the draft on this point, such as :
>
> Note while protocol operations allow copying data between conventional
> datastores, the read-only nature of datastores such as <system> and
> <intended> restricts copying data into them.
>
> Thoughts?
>
>
>
> 2.- It would be nice to update the terminology to include the new
> definition of <intended>, in addition to its description in Section 1.3.
>
> [Qiufang] This draft does not update the definition of <intended> (i.e.,
> "intended configuration datastore" term in
> https://datatracker.ietf.org/doc/html/rfc8342#section-3), it updates the
> meaning of "intended" origin metadata annotation defined in
> https://datatracker.ietf.org/doc/html/rfc8342#section-5.3.4.
>
> I am unsure if this can be a standalone term, as it is more about a
> specific value (identity) of the origin annotation. Note the "origin"
> itself is formally defined in the terminology section of 8342 ("intended"
> is one of its value).
>
>
>
>
>
> 3.- The document describes <system> as a configuration datastore, but the
> way <system> behaves closely resembles default system behavior. The values
> in <system> are created by the system, can be overridden by the user, and
> reappear when the user removes the override. It is therefore unclear
> whether <system> is intended to represent what the user intends to
> configure, or whether it represents system-provided default values that
> apply when the user has not configured anything. In other words, is
> <system> intended to express configuration intent, or system-provided
> defaults, capabilities, or behavior that fill in missing intent (i.e., that
> apply when the user has not configured anything)? A brief clarification in
> the document would help avoid this ambiguity.
>
> [Qiufang] <system> serves as a read-only source system defined
> configuration, the configuration in <system> comes and goes, which is
> beyond the control of clients. While clients can interact with system
> configuration (by editing <running>), nothing affects the contents of
> <system>. Note <running> holds the configuration provided by clients,
> <intended> holds the configuration intended to be applied by the device,
> <operational> holds the configuration successfully applied by the device.
> Given all these definition in this draft and 8342 , and what is clarified
> in
> https://datatracker.ietf.org/doc/html/draft-ietf-netmod-system-config-16#section-4,
> is there anything else that you think needs to be clarified in the draft?
>
>
>
>
>
> 4.- For clarity, how are override semantics expected to behave across a
> reboot?
>
> What happens to <running> when the device reboots?
>
> [Qiufang] Typically <running> contents will not be lost across reboots,
> but <system> contents will be reloaded (e.g., a hardware may be absent now
> that was present before), so <intended> will also be updated immediately
> when <system> changes (<intended> reflects the merging results of <system>
> and <running>).
>
> The draft says: "Whenever configuration in <system> changes, the server
> MUST also immediately update and validate <intended>."
>
> You may also see https://datatracker.ietf.org/doc/html/rfc8342#section-5.1
> for detailed definition of <running> and <intended>.
>
>
>
> 5.- If <system> is read-only to clients but can change due to upgrades or
> hardware events, could it be clarified whether clients should expect
> <system> to remain stable for the duration of an operation, or whether it
> may change at any time?
>
> [Qiufang] Given system may change if there are system events or resource
> changes, I don’t think client should expect <system> to remain stable, but
> the draft also states notification can be leveraged to learn what has been
> updated. Anything else that needs to be clarified then given what is in
> https://datatracker.ietf.org/doc/html/draft-ietf-netmod-system-config-16#section-6.1?
>
>
>
>
> 6.- RFC 8342 defines configuration transformations as occurring between
> <running> and <intended>. Section 4 of this draft states that, if <system>
> or <running> includes configuration that requires further transformation,
> such transformations MUST be performed before merging.
>
>
>
> Given this, could it be clarified:
>
>
>
> 6.1.- whether transformations are applied independently to <running> and
> <system>,
>
> [Qiufang] Have added that "..., configuration transformations MUST be
> performed independently to each datastore before <running> is merged with
> <system>."
>
> 6.2.- whether <system> is already fully transformed before it is exposed,
> and
>
> [Qiufang] The document already says that <system>/<running> may include
> configuration that requires further transformation (e.g., template
> expansion, inactive configuration removal), this implies that
> <system>/<running> is not transformed when exposed. Fig.1 also implies that
> it is <intended> that contains the configuration after transformation. Does
> this make sense?
>
> 6.3.- whether transformations are persistent or recomputed each time
> <system> and <running> are processed?
>
> [Qiufang] This might depends on whether the template/inactive
> configuration has changed. For example, if there are new templates defined
> in <system>, transformations must be done to update <intended>, otherwise,
> I feel that this is implementation-specific details to decide whether to
> re-transform each time to update <intended>. Regardless of the
> method/approach, the content of <intended> remains unaffected, and
> interoperability is not impacted.
>
>
>
> 7.- Section 6.3 allows overriding system-provided settings only when the
> server permits it. Thus:
>
>
>
> 7.1.- How can a client determine which nodes can be overridden?
>
> [Qiufang] The document has a reference to
> draft-ietf-netmod-immutable-flag, which defines an immutable flag to allow
> the client to discover the immutability of system configuration.
>
> 7.2.- Is the set of overridable nodes fixed, or can it change at runtime?
>
> [Qiufang] This is also documented in the immutable-flag draft that (
> https://datatracker.ietf.org/doc/html/draft-ietf-netmod-immutable-flag-06#section-3)
> :
>
>    " The immutability of any configuration data,
>
>    and the value of any immutable configured data node, MUST only change
>
>    via software upgrade, hardware resources change, or license change."
>
> 7.2.- If a node is marked as configurable in the YANG schema but the
> server may still forbid overriding it, how should clients interpret and
> rely on that information?
>
> [Qiufang] Clients should interpret the YANG schema's config true
> declaration as indicating that a node is conceptually configurable, but
> they must rely on the runtime "immutable" annotation to determine actual
> immutability. Immutable-flag has some use cases for this, e.g., some system
> defined list entries are immutable, but clients may define their own list
> entries, and those are mutable. Thus the list should be "config true".
>
> This is not to say that servers must have system configuration that cannot
> be overridden, but to document an existing behavior implemented by servers
> today.
>
>
>
>
>
> Nits
>
> 8.- Section 8.2- datatstore --> datastore ?
>
> [Qiufang] Fixed.
>
> 9.- Section 1. some implementations defines --> some implementations define
>
> [Qiufang] Fixed.
>
> 10.- the descendant nodes of system-defined configuration --> the
> descendant nodes of system-defined configurations
>
> [Qiufang] This is the one that I tend to keep it in the singular, as we
> want to treat "system-defined configuration" as an uncountable, collective
> concept, instead of enumerate distinct configurations.
>
> 11.- Section 2.1: irrespective of physical resource present or not, a
> special functionality enabled or not --> irrespective of whether physical
> resources are present or whether a special functionality is enabled?
>
> [Qiufang] Fixed.
>
> 12.- Section 3: manage operations --> management operations ?
>
> [Qiufang] Fixed. Thanks for spotting this.
>
>
>
> Thanks for this document,
>
>
>
> Ines.
>
>
>
> Best Regards,
>
> Qiufang //co-author
>
>
>
>
>
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