Re: [Netconf] [Gen-art] Genart last call review of draft-ietf-netconf-nmda-netconf-06

Martin Bjorklund <mbj@tail-f.com> Tue, 07 August 2018 12:20 UTC

Return-Path: <mbj@tail-f.com>
X-Original-To: netconf@ietfa.amsl.com
Delivered-To: netconf@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 0B465130E59; Tue, 7 Aug 2018 05:20:30 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.9
X-Spam-Level:
X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VjYesMALljX4; Tue, 7 Aug 2018 05:20:28 -0700 (PDT)
Received: from mail.tail-f.com (mail.tail-f.com [46.21.102.45]) by ietfa.amsl.com (Postfix) with ESMTP id 7FA7B1252B7; Tue, 7 Aug 2018 05:20:28 -0700 (PDT)
Received: from localhost (unknown [173.38.220.61]) by mail.tail-f.com (Postfix) with ESMTPSA id 77AE41AE0144; Tue, 7 Aug 2018 14:20:27 +0200 (CEST)
Date: Tue, 07 Aug 2018 14:20:26 +0200 (CEST)
Message-Id: <20180807.142026.317034485671058801.mbj@tail-f.com>
To: j.schoenwaelder@jacobs-university.de
Cc: christer.holmberg@ericsson.com, gen-art@ietf.org, ietf@ietf.org, draft-ietf-netconf-nmda-netconf.all@ietf.org, netconf@ietf.org
From: Martin Bjorklund <mbj@tail-f.com>
In-Reply-To: <20180807121452.2c7k7mlwfeoxykoa@anna.jacobs.jacobs-university.de>
References: <16f7bca5d58b4d69a3e1618b8ba9dbf5@ericsson.com> <20180807121452.2c7k7mlwfeoxykoa@anna.jacobs.jacobs-university.de>
X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO)
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/netconf/VOFVGFJK7vLMxFD2L9e_udTt7P0>
Subject: Re: [Netconf] [Gen-art] Genart last call review of draft-ietf-netconf-nmda-netconf-06
X-BeenThere: netconf@ietf.org
X-Mailman-Version: 2.1.27
Precedence: list
List-Id: Network Configuration WG mailing list <netconf.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/netconf>, <mailto:netconf-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/netconf/>
List-Post: <mailto:netconf@ietf.org>
List-Help: <mailto:netconf-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/netconf>, <mailto:netconf-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 07 Aug 2018 12:20:30 -0000

Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> wrote:
> On Tue, Jul 31, 2018 at 02:27:36PM +0000, Christer Holmberg wrote:
> > 
> > >> Related to that, it would also be good to have an interoperability
> > >> statement, saying that implementations that implement the draft will
> > >> still work with implementations that do not.
> > >
> > > This primarily concerns clients: They need to be able to fallback to
> > > using <edit-config> instead of <edit-data> and <get> instead of
> > > <get-data> if they communicate with a non NMDA NETCONF server. I am
> > > not sure whether this is a "SHOULD be able to fallback" or a "MUST be
> > > able to fallback".
> > 
> > If you use MUST, you guarantee that fallback will always work (assuming implementations follow the spec). If you use SHOULD, I think you'll need some additional discussion on when it doesn't apply, what to do then, etc.
> > 
> > So, my suggestion (from a reviewer perspective) would be MUST.
> >
> 
> I am not sure about this. It is very well possible that in a few years
> client implementations may require NMDA and instead of trying a
> fallback they stop if the peer does not support NMDA. The complexity
> of clients varies widely, ranging from implementations that can hide
> the complexities behind an API to simple scripts without much fallback
> complexity. If we write MUST, it will be ignored in practice by a
> certain fraction of clients.

I agree.  I don't even think we should write SHOULD.  IMO we shouldn't
make such requirements on the clients at all.


/martin