Re: [netmod] New Version Notification for draft-verdt-netmod-yang-versioning-reqs-01.txt

Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> Fri, 09 November 2018 15:13 UTC

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Date: Fri, 9 Nov 2018 16:13:47 +0100
From: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
To: Martin Bjorklund <mbj@tail-f.com>
CC: <andy@yumaworks.com>, <netmod@ietf.org>
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Subject: Re: [netmod] New Version Notification for draft-verdt-netmod-yang-versioning-reqs-01.txt
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On Fri, Nov 09, 2018 at 02:37:29PM +0100, Martin Bjorklund wrote:
> 
> > I think we need to distinguish between the agreement on the
> > requirement, namely that a server should be able to provide support
> > for an old and a new definition, and agreement on the solution.
> > 
> > Do you disagree with the requirement? Or do you disagree with the
> > consequences of implementing multiple versions of the same module
> > for some of the proposed new versioning schemes? Or both?
> 
> I do not agree with the requirement that a server MUST be able to
> support multiple revisions of the same module, which is how I
> interpret 3.2.  If this is not the intention of 3.2, maybe it can be
> clarified.
>

Here is what 3.2 says:

       3.2  The solution MUST provide a mechanism to allow servers to
            simultaneously support clients using different revisions of
            modules.  A client's choice of particular revision of one or
            more modules may restrict the particular revision of other
            modules that may be used in the same request or session.

This does _not_ say servers MUST implement this.

Item 3.2 establishes a requirement and for some solutions it may be
easy to satisfy this requirement, for others it may be more costly to
satisfy this requirement.

The whole requirements exercise becomes a rather pointless exercise if
we remove requirements so that certain solutions look more attractive.
I have not seen a proposal that addresses all requirements and hence
at the end the WG needs to decide which tradeoffs make sense.

/js

-- 
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/>