Re: [netmod] backward compatibility requirements in draft-verdt-netmod-yang-versioning-reqs-00

Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> Sat, 21 July 2018 05:46 UTC

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Date: Sat, 21 Jul 2018 07:45:56 +0200
From: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
To: Andy Bierman <andy@yumaworks.com>
Cc: NetMod WG <netmod@ietf.org>
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Subject: Re: [netmod] backward compatibility requirements in draft-verdt-netmod-yang-versioning-reqs-00
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My understanding is that the MUST puts a requirement on the solution
and the rest is an "allow servers", i.e., something that servers may
want to do. (I was against using RFC 2119 keywords in the first place
for this document.)

/js

On Fri, Jul 20, 2018 at 02:41:33PM -0700, Andy Bierman wrote:
> Hi,
> 
> I strongly object to requirement 3.1:
> 
> 
>     3.1  The solution MUST provide a mechanism to allow servers to
>             support existing clients in a backward compatible way.
> 
> 
> 
> This is not what servers do today at all.
> They provide only one version of an implemented module, as specified in RFC
> 7950.
> 
> It is a vendor and operator decision when to upgrade a server such that
> non-backward compatible changes are made. They must decide if/when it is ok
> based on the client applications in use.
> 
> This requirement says you cannot make backward-incompatible changes
> which completely contradicts requirements 1.1 and 1.2.
> 
> IMO requirement 3.1 should be removed, or change MUST to MAY
> 
> 
> Andy

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> netmod@ietf.org
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-- 
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/>