Re: [Lsr] [netmod] A question on the parameter overriding in draft-ietf-isis-yang-isis-cfg
Martin Bjorklund <mbj@tail-f.com> Mon, 10 June 2019 08:04 UTC
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Date: Mon, 10 Jun 2019 10:04:56 +0200
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To: bill.wu@huawei.com
Cc: j.schoenwaelder@jacobs-university.de, xufeng.liu.ietf@gmail.com, lsr@ietf.org, netmod@ietf.org
From: Martin Bjorklund <mbj@tail-f.com>
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Subject: Re: [Lsr] [netmod] A question on the parameter overriding in draft-ietf-isis-yang-isis-cfg
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Hi, Qin Wu <bill.wu@huawei.com> 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:netmod-bounces@ietf.org] 代表 Juergen > Schoenwaelder > 发送时间: 2019年6月9日 23:28 > 收件人: Xufeng Liu <xufeng.liu.ietf@gmail.com> > 抄送: lsr@ietf.org; NETMOD WG <netmod@ietf.org> > 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 > > netmod@ietf.org > > 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/> > > _______________________________________________ > netmod mailing list > netmod@ietf.org > https://www.ietf.org/mailman/listinfo/netmod > _______________________________________________ > netmod mailing list > netmod@ietf.org > https://www.ietf.org/mailman/listinfo/netmod
- [Lsr] A question on the parameter overriding in d… Xufeng Liu
- Re: [Lsr] [netmod] A question on the parameter ov… Juergen Schoenwaelder
- Re: [Lsr] [netmod] A question on the parameter ov… Qin Wu
- Re: [Lsr] [netmod] A question on the parameter ov… Rob Wilton (rwilton)
- Re: [Lsr] [netmod] A question on the parameter ov… Martin Bjorklund
- Re: [Lsr] [netmod] A question on the parameter ov… Xufeng Liu
- Re: [Lsr] [netmod] A question on the parameter ov… Per Hedeland
- Re: [Lsr] [netmod] A question on the parameter ov… tom petch
- Re: [Lsr] A question on the parameter overriding … stephane.litkowski