Re: analysis of YANG vs. RELAX NG

"Randy Presuhn" <randy_presuhn@mindspring.com> Mon, 03 December 2007 19:59 UTC

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From: "Randy Presuhn" <randy_presuhn@mindspring.com>
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Subject: Re: analysis of YANG vs. RELAX NG
Date: Mon, 3 Dec 2007 12:01:34 -0800
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Hi -

> From: "Ladislav Lhotka" <lhotka@cesnet.cz>
> To: "Andy Bierman" <ietf@andybierman.com>
> Cc: <discuss@apps.ietf.org>
> Sent: Monday, December 03, 2007 10:02 AM
> Subject: Re: analysis of YANG vs. RELAX NG
>

>
> Andy Bierman píše v Po 03. 12. 2007 v 09:21 -0800:
>
> > I strongly agree with Juergen.
> > YANG is based (in part) on 18+ years experience
> > with SNMP and SMI.
>
> And ignoring the additional flexibility XML can provide.

I strongly agree with Andy and Juergen.  "Mushy" definitions
are disastrous for interoperability.

> > It s absolutely forbidden in NM to redefine the syntax and semantics
> > of a managed object in this way.

Agreed.

> Why? Even if I explicitly specify I am using another data model? The
> difference is that if the data model is easily extensible, I can just
> write
>
> import parent-model;
>
> and then 5 lines or so describing the differences, so that it is
> immediately clear what I am doing (and hopefully why). If the
> extensibility is weak, I have to take the parent model, change few lines
> and declare it as a new data model - but the differences are not that
> clear.

Re-use of definitions in the process of creating *new* definitions is
another matter.  The important point is that those new definitions in
no way affect the models on which they were based, and therefore must
not be understood as a redefinition of either the semantics or the
syntax of a managed object.

Randy