Re: [yang-doctors] [netmod] Operational State usage of YANG choices and constraints

[Andy Bierman <[e-mail]>]

On Fri, Jan 19, 2024 at 9:02 AM Acee Lindem <[e-mail]> wrote:

> Along the same lines, what is the sentiment for “mandatory true” data
> nodes for operational state (i.e., “config false” nodes)? Does this make
> sense to identify data nodes the must be returned if the parent node is
> returned?
>
>

What does "must be returned" mean?

Obviously, it does not mean returning the data even if the filters do not
select that node. (I hope)
I used to think it meant conformance  (whether the server must implement or
may implement).
I was told years ago that is not the case. Use if-feature for that. No
if-feature == mandatory-to-implement.

If a client requests the parent subtree, then how would it know the
difference between config=false
nodes that are not present vs. the server just decided not to return them
(even though conformance
to the retrieval operation requires them)?

IMO the mandatory-stmt for config=false nodes does not make any sense at
all.



> Thanks
> Acee
>
>
Andy


> > On Dec 22, 2023, at 2:36 PM, Jürgen Schönwälder
> <[e-mail]> wrote:
> >
> > On Fri, Dec 22, 2023 at 07:22:55PM +0000, Kent Watsen wrote:
> >> With limited experience wrt the impact on servers, as a client, it’s
> always best for the opstate data to be modeled as accurately as possible,
> for better processing and user experience.
> >>
> >
> > What is accurate?
> >
> > I think the answer is "it depends". There are states that a model
> > allows to represent and there are states it does not allow to
> > represent. If a device ends up in a state that the model can't
> > represent, then the device has a problem, From a debugging point of
> > view, the worst is a device in a state that can't be represented
> > propoerly reporting a valid state it is not in.
> >
> > So like everything else, it is a modeling decision, like picking types
> > and everything else. I am not sure that 'as accurate as possible" is a
> > helpful guideline; for operational state I prefer to see as much as
> > possible the device's true state. (But even picking data types for
> > leaves restricts what can be represented, so it is a judgement call.)
> >
> > /js
> >
> > --
> > Jürgen Schönwälder              Constructor University Bremen gGmbH
> > Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
> > Fax:   [phone]         <https://constructor.university/>
>
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