On Wed, Jun 24, 2015 at 7:34 AM, Phil Shafer <[email protected]> wrote:

> Andy Bierman writes:
> >1) defaults are not used in the ephemeral datastore
> >
> >The default-stmt is altered for the ephemeral datastore.
> >Default leafs are ignored (except for XPath evaluation).
> >Otherwise the schema default would always override the configuration.
>
> List instances in the ephemeral datastore with no matching
> instance in the committed datastore would need to have
> default values from the schema.
>
> Think of defaults as the pane of glass that sits behind
> all other planes.
>
>
good point



> >2) XPath hierarchy is based on config-stmt.
> >
> >  config=true context node -> can reference config=true
> >  config=ephemeral context node -> can reference true + ephemeral
> >  config=false context node -> can reference true, ephemeral, false
>
> Are you talking about must/when statements in config false nodes?
>

yes -- all values of config-stmt


>
> I think the key point is that the committed config must be valid
> without references anything else.  The ephemeral config must be
> valid without referencing config false nodes.
>


exactly -- that is what I was trying to say above



>
> >3) must/when evaluation applies only to the datastore indicated by
> >config-stmt
> >     config=true -> running
> >     config=ephemeral -> ephemeral
> >     config=false -> operational
>
> ephemeral nodes should be able to reference config=true nodes.
> An ephemeral interfaces should be able to reference a pre-configured
> filter/policer.  But the reverse would not be true.
>
>

The issue is where to enforce the YANG datastore validation for must/when.
The "portability" of must/when is a general problem, but more datastores
makes
it more complicated



> >4) panes of glass applied to data instances
> >    all running datastore instances are visible in the ephemeral datastore
> >    all ephemeral datastore instances are visible in the operational
> >datastore
>
> What is "all running datastore instances"?
>


All the data instances (like interfaces) are visible in the ephemeral
for the purpose of XPath and path-stmt (leafref) evaluation



>
> >5) admin-foo and oper-foo can go away
> >
> >  The instance of 'admin-temp' in the operational datastore would return
> >  the value in effect, not the desired value, so 'oper-temp' is not needed
> >  and the correlation between config, ephemeral, and operational is
> >maintained
> >  in the common instance-identifier in all 3 datastores
>
> The issues remain: what happens when the set of possible values
> varies between the operational world and the configuration world?
>


New notifications can be defined to let a client know when a data resource
converges or diverges from the configured value.



> How is that expressed in the data model?  "auto" would not be an
> operational value for "duplex".  "none" would not be a valid
> configuration value, but would be the operational value for an
> empty port.
>


good point -- the operational instance would not exist is the status is
'none'



>
> Thanks,
>  Phil
>


Andy
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