Hi,
"Bogaert, Bart (Nokia - BE/Antwerp)" <bart.boga...@nokia.com> wrote: > Hi Martin, > > -----Original Message----- > From: Martin Bjorklund <m...@tail-f.com> > Sent: Thursday, November 28, 2019 9:28 AM > To: Bogaert, Bart (Nokia - BE/Antwerp) <bart.boga...@nokia.com> > Cc: netmod@ietf.org > Subject: Re: [netmod] Question about schema-mount > > Hi, > > "Bogaert, Bart (Nokia - BE/Antwerp)" <bart.boga...@nokia.com> wrote: > > Hi, > > > > We're trying to figure out whether it is possible to define a module > > in the parent schema which would use a node being a leafref to a node > > in a model under a mount point. > > In order for this to work, the leafref target would have to be present > at compile time / design time. RFC 8528 defines Design time, > Implementation time, and Run time mounts, and says: "Design-time > mounts are outside the scope of this document" (see section 1). > > Another alternative would be some new kind of "leafref-like" construct > that supported this. > > What you can do though is to ensure the leaf in the parent module is > of the same type as the mounted node you want to refer to, and explain > in text what the semantics is. > > [Bogaert, Bart] Thanks for this feedback. The use case we're looking > into is the following: > [Bogaert, Bart] A forwarder contains references to interfaces which > are defined as leafref with path /interfaces/interface/name. In the > scope of this question the path would be > /logical-network/elements/logical-network-element/interfaces/interface/name. > Question is: will this work with leafref? No, since a YANG compiler that sees this leafref will fail to find the target and thus throw an error. [side note: a single leafref wouldn't work anyway, since you would the name of both the lne and the name of the interface] > What will the [Bogaert, > Bart] NETCONF server do in such a case, in other word: is it able to > resolve this leafref or do we have to define this as a some kind of > string that includes the name of the logical-network-element and the > name of the interface? Yes, a single string or two leafs, 'lne-name' and 'if-name'. /martin > > I don't seem to find any statement > > that would prohibit this but RFC 8530, referred to from the schema > > mount RFC, uses a leafref to a node in a module which is still in the > > list of YANG modules of the parent (and consequently in the YANG > > library of the parent). > > > > So, using RFC8530 as example: > > > > Instead of lne:bind-lne-name being a leafref to > > /logical-network-elements/logical-network-element/name we would point > > to > > /logical-network-elements/logical-network-element/interfaces/interface/name. > > > > The interfaces YANG module is also part of the YANG library of the > > parent but I'm not so sure whether above construction would work well > > as the information related to the mounted YANG modules is in a YANG > > library different from the parent's YANG library. > > > > Note that there is also some confusion with the examples in RFC8530: > > while the bind-lne-name in the YANG module is a leafref as syntax, the > > examples work with a string as syntax for that same leaf. > > Do you mean the tree diagram? > > [Bogaert, Bart] Correct. > > Best regards, Bart > > module: ietf-interfaces > +--rw interfaces > +--rw interface* [name] > +--rw name string > +--rw lne:bind-lne-name? string > > This looks like a bug to me; it should be a leafref. > > > /martin > _______________________________________________ netmod mailing list netmod@ietf.org https://www.ietf.org/mailman/listinfo/netmod
