Re: [netmod] Choice Case vs Container+When in RFC7950

Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> Tue, 02 April 2019 06:05 UTC

Return-Path: <j.schoenwaelder@jacobs-university.de>
X-Original-To: netmod@ietfa.amsl.com
Delivered-To: netmod@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E0A5E120049 for <netmod@ietfa.amsl.com>; Mon, 1 Apr 2019 23:05:26 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, 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 KmVJR0v4Q9Jj for <netmod@ietfa.amsl.com>; Mon, 1 Apr 2019 23:05:23 -0700 (PDT)
Received: from atlas5.jacobs-university.de (atlas5.jacobs-university.de [212.201.44.20]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id DF2DF120086 for <netmod@ietf.org>; Mon, 1 Apr 2019 23:05:18 -0700 (PDT)
Received: from localhost (demetrius5.irc-it.jacobs-university.de [10.70.0.222]) by atlas5.jacobs-university.de (Postfix) with ESMTP id 44DDEB83; Tue, 2 Apr 2019 08:05:17 +0200 (CEST)
X-Virus-Scanned: amavisd-new at jacobs-university.de
Received: from atlas5.jacobs-university.de ([10.70.0.217]) by localhost (demetrius5.jacobs-university.de [10.70.0.222]) (amavisd-new, port 10032) with ESMTP id Nf3Knq0-Z4Gi; Tue, 2 Apr 2019 08:05:17 +0200 (CEST)
Received: from hermes.jacobs-university.de (hermes.jacobs-university.de [212.201.44.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "hermes.jacobs-university.de", Issuer "Jacobs University CA - G01" (verified OK)) by atlas5.jacobs-university.de (Postfix) with ESMTPS; Tue, 2 Apr 2019 08:05:17 +0200 (CEST)
Received: from localhost (demetrius5.irc-it.jacobs-university.de [10.70.0.222]) by hermes.jacobs-university.de (Postfix) with ESMTP id 2E85C200A8; Tue, 2 Apr 2019 08:05:17 +0200 (CEST)
X-Virus-Scanned: amavisd-new at jacobs-university.de
Received: from hermes.jacobs-university.de ([212.201.44.23]) by localhost (demetrius5.jacobs-university.de [10.70.0.222]) (amavisd-new, port 10028) with ESMTP id BVf4Dj_3mjz5; Tue, 2 Apr 2019 08:05:16 +0200 (CEST)
Received: from exchange.jacobs-university.de (sxchmb03.jacobs.jacobs-university.de [10.70.0.155]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "exchange.jacobs-university.de", Issuer "DFN-Verein Global Issuing CA" (verified OK)) by hermes.jacobs-university.de (Postfix) with ESMTPS id C03E6200A7; Tue, 2 Apr 2019 08:05:16 +0200 (CEST)
Received: from anna.localdomain (10.50.218.117) by sxchmb03.jacobs.jacobs-university.de (10.70.0.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.1591.10; Tue, 2 Apr 2019 08:05:15 +0200
Received: by anna.localdomain (Postfix, from userid 501) id 51FB63007AAA91; Tue, 2 Apr 2019 08:05:13 +0200 (CEST)
Date: Tue, 2 Apr 2019 08:05:13 +0200
From: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
To: Qin Wu <bill.wu@huawei.com>
CC: "netmod@ietf.org" <netmod@ietf.org>
Message-ID: <20190402060513.7eh5kgnc63gxyu7w@anna.jacobs.jacobs-university.de>
Reply-To: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
Mail-Followup-To: Qin Wu <bill.wu@huawei.com>, "netmod@ietf.org" <netmod@ietf.org>
References: <B8F9A780D330094D99AF023C5877DABAA48CDC7A@nkgeml513-mbx.china.huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <B8F9A780D330094D99AF023C5877DABAA48CDC7A@nkgeml513-mbx.china.huawei.com>
User-Agent: NeoMutt/20180716
X-ClientProxiedBy: SXCHMB03.jacobs.jacobs-university.de (10.70.0.155) To sxchmb03.jacobs.jacobs-university.de (10.70.0.155)
Archived-At: <https://mailarchive.ietf.org/arch/msg/netmod/WagQdmE19jdkN85oUWaLCSCwXxI>
Subject: Re: [netmod] Choice Case vs Container+When in RFC7950
X-BeenThere: netmod@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: NETMOD WG list <netmod.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/netmod>, <mailto:netmod-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/netmod/>
List-Post: <mailto:netmod@ietf.org>
List-Help: <mailto:netmod-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/netmod>, <mailto:netmod-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 02 Apr 2019 06:05:27 -0000

I prefer choice since a choice says clearly upfront that what follows
are N alternatives. With when statements, I have to keep all the when
statements in my mind to derive the conclusion that the model defines
alternatives. And the transport leaf in your when construction is
redundant.

/js

On Tue, Apr 02, 2019 at 01:13:52AM +0000, Qin Wu wrote:
> Hi, Folks:
> Choice case seems interchangeable with Container+when, here is the example of Choice case
>      container system {
>        description
>          "Contains various system parameters.";
>        choice services {
>          description
>            "Configure externally available services.";
>          case ssh {
>            description
>              "SSH service-specific configuration.";
>            // more leafs, containers, and stuff here...
>          }
>          case tls {
>            description
>              "TLS service-specific configuration.";
>            // more leafs, containers, and stuff here...
>          }
>        }
>      }
> I think it can be replaced with container+when representation as follows:
>     container system {
>        description
>          "Contains various system parameters.";
>        container services {
>          description
>            "Configure externally available services.";
>          leaf transport {
>            enum ssh {
>             description
>              "ssh";
>           }
>            enum tls {
>            description
>             "tls";
>           }
>          }
>          container "ssh" {
>            when "../transport=ssh" {
>             description
>             "active only when the transport is ssh";
>            }
>            description
>              "SSH service-specific configuration.";
>            // more leafs, containers, and stuff here...
>          }
>          container "tls" {
>            when "../transport=tls" {
>             description
>             "active only when the transport is tls";
>            }
>            description
>              "TLS service-specific configuration.";
>            // more leafs, containers, and stuff here...
>          }
>        }
>      }
> However I didn't see any guidance on when to use Choice case or when to use Container+when?
> Any thought about this?
> 
> -Qin

> _______________________________________________
> netmod mailing list
> netmod@ietf.org
> https://www.ietf.org/mailman/listinfo/netmod


-- 
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/>