Re: [OSPF] [Isis-wg] Mail regarding draft-ietf-ospf-segment-routing-extensions

Rob Shakir <rjs@rob.sh> Mon, 29 December 2014 10:16 UTC

Return-Path: <rjs@rob.sh>
X-Original-To: ospf@ietfa.amsl.com
Delivered-To: ospf@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1FD591A00A8; Mon, 29 Dec 2014 02:16:46 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.91
X-Spam-Level:
X-Spam-Status: No, score=-1.91 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01] autolearn=ham
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 W66pFQ97dFW2; Mon, 29 Dec 2014 02:16:43 -0800 (PST)
Received: from cappuccino.rob.sh (cappuccino.rob.sh [IPv6:2a03:9800:10:4c::cafe:b00c]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D3BAE1A00AE; Mon, 29 Dec 2014 02:16:42 -0800 (PST)
Received: from [86.180.124.183] (helo=[192.168.1.78]) by cappuccino.rob.sh with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from <rjs@rob.sh>) id 1Y5XNK-0000Oy-OG; Mon, 29 Dec 2014 10:16:34 +0000
Mime-Version: 1.0 (Mac OS X Mail 8.0 \(1990.1\))
Content-Type: text/plain; charset="utf-8"
From: Rob Shakir <rjs@rob.sh>
In-Reply-To: <BY1PR0501MB1381BC773F791EF11B528899D5510@BY1PR0501MB1381.namprd05.prod.outlook.com>
Date: Mon, 29 Dec 2014 10:16:33 +0000
Content-Transfer-Encoding: quoted-printable
Message-Id: <1A0EBDEF-FF86-413E-91DB-D1E58BCDC861@rob.sh>
References: <BY1PR0501MB13819883015276791F20D631D5540@BY1PR0501MB1381.namprd05.prod.outlook.com> <54A10B35.4030301@cisco.com> <BY1PR0501MB1381B131A68B321264B7E930D5510@BY1PR0501MB1381.namprd05.prod.outlook.com> <54A10E78.6030006@cisco.com> <BY1PR0501MB1381610E47F46E81528B5416D5510@BY1PR0501MB1381.namprd05.prod.outlook.com> <54A11188.8040301@cisco.com> <BY1PR0501MB1381860D81EE3DF32A76B6D7D5510@BY1PR0501MB1381.namprd05.prod.outlook.com> <54A1173D.6000200@cisco.com> <8673017E-4E86-4D2E-8522-DF49ED869E2D@rob.sh> <BY1PR0501MB13811064F9C6F3FE646CDEBCD5510@BY1PR0501MB1381.namprd05.prod.outlook.com> <EE01350B-D88A-4797-B6D8-8E003405C562@rob.sh> <BY1PR0501MB1381BC773F791EF11B528899D5510@BY1PR0501MB1381.namprd05.prod.outlook.com>
To: Shraddha Hegde <shraddha@juniper.net>
X-Mailer: Apple Mail (2.1990.1)
Archived-At: http://mailarchive.ietf.org/arch/msg/ospf/23UNYUOhdiM9B6gxe9zAwTd8h6A
Cc: "ospf@ietf.org" <ospf@ietf.org>, "draft-ietf-isis-segment-routing-extensions@tools.ietf.org" <draft-ietf-isis-segment-routing-extensions@tools.ietf.org>, "draft-ietf-ospf-segment-routing-extensions@tools.ietf.org" <draft-ietf-ospf-segment-routing-extensions@tools.ietf.org>, "isis-wg@ietf.org" <isis-wg@ietf.org>
Subject: Re: [OSPF] [Isis-wg] Mail regarding draft-ietf-ospf-segment-routing-extensions
X-BeenThere: ospf@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: The Official IETF OSPG WG Mailing List <ospf.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ospf>, <mailto:ospf-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/ospf/>
List-Post: <mailto:ospf@ietf.org>
List-Help: <mailto:ospf-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ospf>, <mailto:ospf-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 29 Dec 2014 10:16:46 -0000

Shraddha,

Do you see deployments today where there are configured RSVP-TE FRR paths, but there are loose routed LSPs that request no FRR protection?

Such a datapoint would be interesting to figure out whether we currently have demand for this approach — but clearly this would not necessarily say anything about future requirements.

Cheers,
r.

> On 29 Dec 2014, at 10:12, Shraddha Hegde <shraddha@juniper.net> wrote:
> 
> Rob/Peter,
> 
> 
> I think today there are networks which run only on SPF paths and having a facility of "unprotected node-sid" is useful in my opinion 
> Rather than not providing such a facility in the protocol at all.
> 
> I agree that if there is no sufficient interest on the list it can be dropped. 
> I hope we can wait until the holiday season to get over to hear others opinion on this.
> 
> Rgds
> Shraddha
> 
> 
> -----Original Message-----
> From: Rob Shakir [mailto:rjs@rob.sh] 
> Sent: Monday, December 29, 2014 3:11 PM
> To: Shraddha Hegde
> Cc: Peter Psenak; draft-ietf-ospf-segment-routing-extensions@tools.ietf.org; draft-ietf-isis-segment-routing-extensions@tools.ietf.org; ospf@ietf.org; isis-wg@ietf.org
> Subject: Re: [Isis-wg] Mail regarding draft-ietf-ospf-segment-routing-extensions
> 
> 
>> On 29 Dec 2014, at 09:33, Shraddha Hegde <shraddha@juniper.net> wrote:
>> 
>> <Shraddha> It is likely that some application wants to use the node-sids when the strict path for performance sensitive traffic matches with that of the SPF  for some segments or for the entire path. 
>> 
> 
> There is nothing stopping it doing so, but it cannot deterministically say that the path will remain coherent with the one that it expects for multiple reasons:
> 
> 1) Nodes along the path may select a subset of ECMPs, the performance of which may vary.
> 2) There may be topology changes (triggered by failure or not) which mean that the shortest-path may change.
> 
> Given that either of these can result in performance variance, it’s very likely (from a practical standpoint) that the traffic must be able to live with FRRs too - hence it being unclear to me that there’s a requirement for an ‘unprotected’ Node SID.
> 
> r.