Re: [L3sm] Comments on draft-ietf-l3sm-l3vpn-service-model

Benoit Claise <> Wed, 22 July 2015 12:53 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 618F21B3306 for <>; Wed, 22 Jul 2015 05:53:05 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -13.911
X-Spam-Status: No, score=-13.911 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, J_CHICKENPOX_12=0.6, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id 9M9mEzinyJJj for <>; Wed, 22 Jul 2015 05:53:03 -0700 (PDT)
Received: from ( []) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id D6C2F1A1B5D for <>; Wed, 22 Jul 2015 05:53:00 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;;; l=2742; q=dns/txt; s=iport; t=1437569581; x=1438779181; h=subject:to:references:from:message-id:date:mime-version: in-reply-to:content-transfer-encoding; bh=6OI5/ia0mxx/AWA3RbOYCozxsgmCwhjawKJl4J3wV0k=; b=K6nbWSobCSaG0V9I2FkZyz4FiGwkVY83GwCstB8YpPrsKvXh/USw0PV8 j867/nd8KPLeak/Yat1ktuYZZ7cBdkzGh2jYj1P78pRJ8jVGJWVPweHac CI7hbFEfLAr9pKAGZmN6h/fQbYZph1nkLWCU4NKdpTpMmv0Kt4s8NhaXR A=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-AV: E=Sophos;i="5.15,523,1432598400"; d="scan'208";a="595566528"
Received: from (HELO ([]) by with ESMTP; 22 Jul 2015 12:52:59 +0000
Received: from [] ( []) by (8.14.5/8.14.5) with ESMTP id t6MCqtjf022493; Wed, 22 Jul 2015 12:52:55 GMT
To:, 'Kireeti Kompella' <>,
References: <> <029d01d0c479$dc07ccd0$94176670$>
From: Benoit Claise <>
Message-ID: <>
Date: Wed, 22 Jul 2015 14:52:54 +0200
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1
MIME-Version: 1.0
In-Reply-To: <029d01d0c479$dc07ccd0$94176670$>
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Transfer-Encoding: 8bit
Archived-At: <>
Subject: Re: [L3sm] Comments on draft-ietf-l3sm-l3vpn-service-model
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: L3VPN Service YANG Model discussion group <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 22 Jul 2015 12:53:05 -0000

Dear all,

+1 to Adrian's message.

My ocean-boiling concern has always been: in order to do the perfect job 
of modularity/grouping/augmentation, we should investigate all existing 
and potential future services. And the L2VPN are technology specific, so 
it's start to be difficult.

This is the reason why the charter is so strict and only focuses on L3VPN.

Obviously, we should follow Adrian's advice: "But some early, 
precautionary modularisation is not going to be a problem so long as we 
don't spend too long arguing about exactly what to modularise."

Regards, Benoit
> Hello Kireeti,
> Welcome to the party.
>> 1) At a high level, I would like to see services as compositions (mash-ups) of
>> service elements.  This is a generalization of the comments that Aijun made.
>> Here’s why.  As we (either the IETF or other bodies, or SPs on their own) define
>> other services, it would be very convenient to be able to reuse these service
>> elements.
> I completely take your point, but...
> When we started the L3SM work we were not certain (and some remain uncertain) that the problem could be addressed even for one of our most simple services (the L3VPN) let alone for a more generic concept of services. Therefore, the WG was explicitly tasked (read the charter) to work with focus and attention on L3VPN only and to exclude consideration of other services.
> That, in itself, does not predicate against modularisation, but it does make it hard to consider which modules to have (since some aspects of modularisation must surely consider the other services that might use the modules).
> Therefore, my expectation of progress is...
> - Continue to progress L3SM towards completion
> - Publish an RFC (if it can be agreed and done)
> - Start work on another similar service model (e.g. L2SM)
>     - If there is energy
>     - If the IESG gives us permission
> - Look for commonalities and modularisations
>     - If they exist it may be necessary to revise L3SM
> So, from some aspects this does not look optimal. Perhaps you could have made this comment during chartering.
> But from another perspective it enables some initial progress in a new subject space that the IETF has not previously attempted. If it is successful we can dig deeper.
> Overall (setting aside the fact that we are anyway constrained by our charter) I have a fear of ocean-boiling. But some early, precautionary modularisation is not going to be a problem so long as we don't spend too long arguing about exactly what to modularise.
> Adrian
> _______________________________________________
> L3sm mailing list