On Fri, Jul 31, 2015 at 5:45 AM, Ladislav Lhotka <lho...@nic.cz> wrote:
>
> > On 31 Jul 2015, at 14:40, Andy Bierman <a...@yumaworks.com> wrote:
> >
> >
> >
> > 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)
>
> I understood Martin’s proposal so that a device that doesn’t support an
> extension used in modules it advertises will have to put it in a
> “not-supported” deviation.
>
>
So features are all "not-supported" by default. but extensions,
which a tool MAY ignore, are all supported by default?
A server would be required to identify and remember all
extensions used? And what about nested extensions:
acme:foo test1 {
acme:foo2 test2;
}
The server would be required to completely parse all extensions,
and not skip over them? Just to list them as deviations?
I think extensions should be like features and the server should
advertise them if they are supported.
I don't agree that "external-stmt" should be under YANG conformance
at all. That is why MAY skip over is in the text. A tool that
understands the extension is purely optional.
Lada
>
>
Andy
> >
> >
> >
> > 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
> >
>
> --
> Ladislav Lhotka, CZ.NIC Labs
> PGP Key ID: E74E8C0C
>
>
>
>
>
_______________________________________________
netmod mailing list
netmod@ietf.org
https://www.ietf.org/mailman/listinfo/netmod
