On Fri, Jul 31, 2015 at 1:12 AM, Ladislav Lhotka <lho...@nic.cz> wrote:
> Martin Bjorklund <m...@tail-f.com> writes:
>
> > Andy Bierman <a...@yumaworks.com> wrote:
> >> On Thu, Jul 30, 2015 at 10:41 AM, Martin Bjorklund <m...@tail-f.com>
> wrote:
> >>
> >> > Andy Bierman <a...@yumaworks.com> wrote:
> >> > > On Wed, Jul 29, 2015 at 10:51 AM, Martin Bjorklund <m...@tail-f.com>
> >> > wrote:
> >> > >
> >> > > > Andy Bierman <a...@yumaworks.com> wrote:
> >> > > > > Hi,
> >> > > > >
> >> > > > > I understand the intent is that an implementation of NACM
> >> > > > > has to understand these NACM extensions. I agree with Lada
> >> > > > > that the YANG text about MAY ignore extensions casts doubt
> whether
> >> > > > > this sort of NACM rule is enforceable or specified correctly.
> >> > > >
> >> > > > So do you agree that it would be a good idea to clarify this
> >> > > > according to Juergen's suggestion?
> >> > > >
> >> > > >
> >> > > >
> >> > > Not really.
> >> > > Pretending the extension is just another description-stmt
> >> > > does not really fix anything.
> >> > >
> >> > > A real YANG statement like config-stmt or a new statement
> >> > > called ephemeral-stmt can be modified with refine-stmt
> >> > > or deviate-stmt. This can never happen for
> >> > > an external statement.
> >> >
> >> > There are two separate issues here:
> >> >
> >> > 1) It seems we are in agreement that if a model uses an extension
> >> > statement, it is normative (like ietf-system's usage of nacm:*).
> >> >
> >> > Should we somehow clarify this in 6020bis?
> >> >
> >> > 2) Extensions cannot be refined or deviated.
> >> >
> >> > Actually, the *syntax* rules allows things like:
> >> >
> >> > deviation /x:foo {
> >> > deviate replace {
> >> > i2rs:ephemeral true;
> >> > }
> >> > }
> >> >
> >> > I agree that it not clear what this means, but we could also
> >> > clarify this in 6020bis.
> >> >
> >> >
> >>
> >> But this will take even longer than just defining the statements that
> >> are needed for ephemeral state, so no point in doing that.
> >>
> >> The text in 7.18.3.2 clearly does not support the example above at all.
> >
> > The grammar allows extensions everywhere, so the example is (as I
> > wrote) syntactically valid.
> >
> >> Only one of the keywords listed in the table are supported.
> >
> > The text doesn't say so, and anyway my point was that - regardless of
> > the outcome of the ephemeral dicussion - it might be a good a idea to
> > clarify that extensions can be deviated as well.
>
> +1
>
So you are saying that a tool MAY ignore any extension, except
inside a deviation-stmt? Then it becomes mandatory to support?
Or do you mean:
Yes you can put extension-stmts anywhere, but also, yes the tool
MAY ignore every single extension (everywhere, including inside a
deviation-stmt)
> Lada
>
Andy
>
> >
> > /martin
> >
> >>
> >>
> >> The substatement's keyword MUST match a corresponding
> >> keyword in the target node, and the argument's string MUST be equal
> >> to the corresponding keyword's argument string in the target node.
> >>
> >> The deviates's Substatements
> >>
> >> +--------------+---------+-------------+
> >> | substatement | section | cardinality |
> >> +--------------+---------+-------------+
> >> | config | 7.19.1 | 0..1 |
> >> | default | 7.6.4 | 0..1 |
> >> | mandatory | 7.6.5 | 0..1 |
> >> | max-elements | 7.7.4 | 0..1 |
> >> | min-elements | 7.7.3 | 0..1 |
> >> | must | 7.5.3 | 0..n |
> >> | type | 7.4 | 0..1 |
> >> | unique | 7.8.3 | 0..n |
> >> | units | 7.3.3 | 0..1 |
> >> +--------------+---------+-------------+
> >>
> >>
> >>
> >>
> >> > > IMO ephemeral data support needs to be a real statement
> >> > > that can be used with refine-stmt and deviate-stmt.
> >> > > It is a real property of a data node.
> >> >
> >> > Note: it is still not clear that such a statement (base or extension)
> >> > is needed at all.
> >> >
> >> >
> >>
> >> Maybe not to you, but according to the I2RS ephemeral requirements,
> >> it is needed, so unless you have a better plan, this is the default.
> >>
> >> Explain how ephemeral state can be identified within a data node.
> >> It must be possible to use groupings to define such data nodes.
> >> If must be possible to refine these groupings.
> >> It must be possible for a vendor to write deviation statements.
> >> All YANG tools must recognize the ephemeral data property.
> >> It should not be isolated to a particular YANG module, which would
> >> create a dependency in all future YANG modules.
> >>
> >>
> >> Andy
> >>
> >>
> >>
> >>
> >>
> >> >
> >> > /martin
> >> >
>
> --
> Ladislav Lhotka, CZ.NIC Labs
> PGP Key ID: E74E8C0C
>
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