Hi,
Qin Wu <[email protected]> wrote:
> I think what they are looking for in RFC7950 is generic overridden
> rule, i.e., a parent node statement can be overridden by its child
> node substatement.
See Per's reply to the netmod list. In summary, in this case you
should do:
container priority {
leaf value {
type uint8;
default 64;
}
container level-1 {
leaf value {
type uint8;
description
"If not configured, use the value of ../../value.";
}
}
container level-2 {
leaf value {
type uint8;
description
"If not configured, use the value of ../../level-1/value.";
}
}
}
/martin
>
> -Qin
> -----邮件原件-----
> 发件人: netmod [mailto:[email protected]] 代表 Juergen
> Schoenwaelder
> 发送时间: 2019年6月9日 23:28
> 收件人: Xufeng Liu <[email protected]>
> 抄送: [email protected]; NETMOD WG <[email protected]>
> 主题: Re: [netmod] A question on the parameter overriding in
> draft-ietf-isis-yang-isis-cfg
>
> Hi,
>
> YANG does not have 'levels'. This seems to be an ISIS specific
> question you should ask on the ISIS list.
>
> /js
>
> On Sun, Jun 09, 2019 at 10:35:11AM -0400, Xufeng Liu wrote:
> > In Section 2.3. and many other locations, the current IS-IS model
> > applies the parameter overriding rule as below:
> >
> > [Quote]:
> >
> > 2.3
> > <https://tools.ietf.org/html/draft-ietf-isis-yang-isis-cfg-35#section-2..3>.
> > Per-Level Parameters
> >
> >
> > Some parameters allow a per level configuration. In this case, the
> > parameter is modeled as a container with three configuration
> > locations:
> >
> > o a top-level container: corresponds to level-1-2, so the
> > configuration applies to both levels.
> >
> > o a level-1 container: corresponds to level-1 specific parameters.
> >
> > o a level-2 container: corresponds to level-2 specific parameters.
> >
> > +--rw priority
> > | +--rw value? uint8
> > | +--rw level-1
> > | | +--rw value? uint8
> > | +--rw level-2
> > | +--rw value? uint8
> >
> > Example:
> >
> > <priority>
> > <value>250</value>
> > <level-1>
> > <value>100</value>
> > </level-1>
> > <level-2>
> > <value>200</value>
> > </level-2>
> > </priority>
> >
> > An implementation SHOULD prefer a level specific parameter over a
> > level-all parameter. As example, if the priority is 100 for the
> > level-1, 200 for the level-2 and 250 for the top-level configuration,
> > the implementation should use 100 for the level-1 and 200 for the
> > level-2.
> >
> > [End of Quote]
> >
> >
> > In the model, all three value leaves above have a default statement
> > “default 64”, which brings up my question for the following example:
> >
> >
> > <priority>
> > <value>250</value>
> > <level-1>
> > <value>100</value>
> > </level-1>
> > </priority>
> >
> >
> > The user does not provide a configured value for level-2. According to
> > Section 7.6.1. of RFC7950, because the default value is in use, “the
> > server MUST operationally behave as if the leaf was present in the
> > data tree with the default value as its value”. This means the
> > priority value for level-2 will be 64 (the default value), so the
> > value 250 can never take effect as intended in the above quoted
> > Section 2.3.
> >
> >
> > Is my understanding correct?
> >
> >
> > Since this is a generic question, I am CC’ing NETMOD WG too.
> >
> >
> > Thanks,
> >
> > - Xufeng
>
> > _______________________________________________
> > netmod mailing list
> > [email protected]
> > https://www.ietf.org/mailman/listinfo/netmod
>
>
> --
> Juergen Schoenwaelder Jacobs University Bremen gGmbH
> Phone: +49 421 200 3587 Campus Ring 1 | 28759 Bremen | Germany
> Fax: +49 421 200 3103 <https://www.jacobs-university.de/>
>
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