Re: [spring] SRV6 - SR-TE support & Flex Alg support ? and comparison and contrast of those two steering strategies
Peter Psenak <ppsenak@cisco.com> Sun, 05 April 2020 16:09 UTC
Return-Path: <ppsenak@cisco.com>
X-Original-To: spring@ietfa.amsl.com
Delivered-To: spring@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id ED4383A0D7D for <spring@ietfa.amsl.com>; Sun, 5 Apr 2020 09:09:49 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.601
X-Spam-Level:
X-Spam-Status: No, score=-9.601 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=cisco.com
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 dARiyk709TlZ for <spring@ietfa.amsl.com>; Sun, 5 Apr 2020 09:09:47 -0700 (PDT)
Received: from aer-iport-2.cisco.com (aer-iport-2.cisco.com [173.38.203.52]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 14BCE3A0D7A for <spring@ietf.org>; Sun, 5 Apr 2020 09:09:46 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=6623; q=dns/txt; s=iport; t=1586102987; x=1587312587; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=+202DDORlF4plh3akhS2OFBHq5yPQGd5hXr5HTUqLW0=; b=gz6aZXeeQKvPSd3qMhgsCZrhG9KeGzgxh3kSYkndUGuOvHHbB1oX0f76 NIDCstSe1JdSq+Qv3CXrC8E7dmrV7HJXpBc6DnNuOz+qO1a4VZuhix56E IFBfZOmINE8H16ET05+0IFUKs91AwxfkHImiM5tuJY7n8oy8FpWIOgreM s=;
X-IronPort-AV: E=Sophos;i="5.72,348,1580774400"; d="scan'208";a="25067662"
Received: from aer-iport-nat.cisco.com (HELO aer-core-2.cisco.com) ([173.38.203.22]) by aer-iport-2.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 05 Apr 2020 16:09:44 +0000
Received: from [10.60.140.51] (ams-ppsenak-nitro2.cisco.com [10.60.140.51]) by aer-core-2.cisco.com (8.15.2/8.15.2) with ESMTP id 035G9iwF029996; Sun, 5 Apr 2020 16:09:44 GMT
To: Gyan Mishra <hayabusagsm@gmail.com>, "Ketan Talaulikar (ketant)" <ketant@cisco.com>
Cc: SPRING WG <spring@ietf.org>
References: <CABNhwV2RVoRqd9HPRSHMarFvmL6cJayq-igbLOSpHtcUDWkXPw@mail.gmail.com> <a1433334-cf0b-dca7-fb3a-c08dd9a33f20@cisco.com> <MW3PR11MB4570FFE64C1AD31B6ECEEF73C1C80@MW3PR11MB4570.namprd11.prod.outlook.com> <CABNhwV3p68vZHUnJAcgdo3fT=cAf0-df1ntJaAGbcvb66cDdHQ@mail.gmail.com>
From: Peter Psenak <ppsenak@cisco.com>
Message-ID: <14b27fd2-9e08-2942-7e1d-8a413bb0427c@cisco.com>
Date: Sun, 05 Apr 2020 18:09:44 +0200
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.7.0
MIME-Version: 1.0
In-Reply-To: <CABNhwV3p68vZHUnJAcgdo3fT=cAf0-df1ntJaAGbcvb66cDdHQ@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Language: en-US
Content-Transfer-Encoding: 8bit
X-Outbound-SMTP-Client: 10.60.140.51, ams-ppsenak-nitro2.cisco.com
X-Outbound-Node: aer-core-2.cisco.com
Archived-At: <https://mailarchive.ietf.org/arch/msg/spring/gCZpcd4x7UYuLg4221HibUEcVsQ>
Subject: Re: [spring] SRV6 - SR-TE support & Flex Alg support ? and comparison and contrast of those two steering strategies
X-BeenThere: spring@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Source Packet Routing in NetworkinG \(SPRING\)" <spring.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/spring>, <mailto:spring-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/spring/>
List-Post: <mailto:spring@ietf.org>
List-Help: <mailto:spring-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/spring>, <mailto:spring-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sun, 05 Apr 2020 16:09:50 -0000
Hi Gyan, On 01/04/2020 03:43, Gyan Mishra wrote: > Thank you both for your feedback. That really helps a lot and clarifies. > > So flex-algo can be used with SR-TE as part of the policy specifying a > delay metric and also be used as part of the IGP flex algo cSPF. yes. > > Their might be some slight nuances but overall as far as features for > both SR-MPLS & SRv6 the SR-TE policy would require binding SID and have > similarities with lose or strict with prefix-sid or ad-sid specified > correct and all same features and functionality. Correct? yes. > > Also for inter-as or inter-domain SR - for both SR-MPLS or SRv6 the > SR-TE w/ binding sid could be used as well in place of traditional > BGP-LU for inter-as or csc. Correct? yes. > > So operators have the option to stay with inter-as BGP-LU or go with > SR-TE which is more attractive and powerful with simplicity. agree. thanks, Peter > > Kind regards > > Gyan > > On Tue, Mar 31, 2020 at 5:15 AM Ketan Talaulikar (ketant) > <ketant@cisco.com <mailto:ketant@cisco.com>> wrote: > > Hi Gyan, > > To add to what Peter has clarified, SR Policy architecture also > supports SRv6 (as you've pointed out in the references) - loose and > strict paths as well as steering for colored BGP routes. > > Thanks, > Ketan > > -----Original Message----- > From: spring <spring-bounces@ietf.org > <mailto:spring-bounces@ietf.org>> On Behalf Of Peter Psenak > Sent: 31 March 2020 13:42 > To: Gyan Mishra <hayabusagsm@gmail.com > <mailto:hayabusagsm@gmail.com>>; SPRING WG <spring@ietf.org > <mailto:spring@ietf.org>> > Subject: Re: [spring] SRV6 - SR-TE support & Flex Alg support ? and > comparison and contrast of those two steering strategies > > Hi Gyan, > > let me comment on the flex-algo aspect. Please see inline: > > On 30/03/2020 23:50, Gyan Mishra wrote: > > > > Does SRv6 support SR-TE and flex Alg? > > yes, it does support both. > > > > > > > Since SRv6 supports native traffic steering with SRH with end prefix > > sid and end.x adjacency sid you can achieve the basic steering and > > ECMP capability with prefix sid lose or strict hop by hop with every > > node specified in SRH SL. > > > > I want to confirm that SRv6 fully supports all of the SR-TE > > capabilities available with SR-MPLS with static lose or strict paths > > and coloring of vpn flows. > > > > From the SR policy draft I did see that section 4 lists segment > types > > and does appear to support SRv6 sid. > > > > > https://tools.ietf.org/html/draft-ietf-spring-segment-routing-policy-0 > > 6 > > > > > > 4 > > > <https://tools.ietf.org/html/draft-ietf-spring-segment-routing-policy-06#section-4>. > > Segment Types > > > > > > > > A Segment-List is an ordered set of segments represented as > <S1, S2, > > ... Sn> where S1 is the first segment. > > > > Based on the desired dataplane, either the MPLS label stack > or the > > SRv6 SRH is built from the Segment-List. However, the > Segment-List > > itself can be specified using different segment-descriptor > types and > > the following are currently defined: > > > > > > Flex Alg - SRv6 support? > > yes. > > > > > Flex Alg is orthogonal to SR TE as it provides IGP extensions for > > constrained SPF versus traditional RSVP or SR-TE providing the > > extensions for cSPF - basically another method of steering which as > > well is very powerful tool for operators. > > > > It does appear SRv6 supports flex Alg draft below. > > yes. > > > > > https://tools.ietf.org/html/draft-ietf-lsr-flex-algo-06 > > > > Abstract > > > > IGP protocols traditionally compute best paths over the network based > > on the IGP metric assigned to the links. Many network > deployments > > use RSVP-TE based or Segment Routing based Traffic Engineering to > > enforce traffic over a path that is computed using different > metrics > > or constraints than the shortest IGP path. This document > proposes a > > solution that allows IGPs themselves to compute constraint based > > paths over the network. This document also specifies a way > of using > > Segment Routing (SR) Prefix-SIDs and SRv6 locators to steer > packets > > along the constraint-based paths. > > > > > > > > What are the benefits of using SR-TE over flex Alg and vice versa? > > you can think of them as different tools in your SR-TE tool set. You > pick them as you need them. They can be used independently in > parallel or can even be combined together to give you even more > flexibility. > > The principal difference is that SR-TE provisions point-to-point > path(s) between two end-points, while flex-algo provides any to any > paths between set of participating nodes. > > > > > Also can SR-TE use flex Alg steered paths as the dynamic cSPF paths? > > yes > > > > > Can SR-TE use and specify flex Alg to be used for traffic steering? > > yes > > thanks, > Peter > > > > > > > Kind regards > > > > > > Gyan > > Verizon > > Cell 301 502-1347 > > -- > > > > Gyan Mishra > > > > Network Engineering & Technology > > > > Verizon > > > > Silver Spring, MD 20904 > > > > Phone: 301 502-1347 > > > > Email: gyan.s.mishra@verizon.com > <mailto:gyan.s.mishra@verizon.com> <mailto:gyan.s.mishra@verizon.com > <mailto:gyan.s.mishra@verizon.com>> > > > > > > > > _______________________________________________ > spring mailing list > spring@ietf.org <mailto:spring@ietf.org> > https://www.ietf.org/mailman/listinfo/spring > > > > -- > > Gyan Mishra > > Network Engineering & Technology > > Verizon > > Silver Spring, MD 20904 > > Phone: 301 502-1347 > > Email: gyan.s.mishra@verizon.com <mailto:gyan.s.mishra@verizon.com> > > >
- [spring] SRV6 - SR-TE support & Flex Alg support … Gyan Mishra
- Re: [spring] SRV6 - SR-TE support & Flex Alg supp… Peter Psenak
- Re: [spring] SRV6 - SR-TE support & Flex Alg supp… Ketan Talaulikar (ketant)
- Re: [spring] SRV6 - SR-TE support & Flex Alg supp… Gyan Mishra
- Re: [spring] SRV6 - SR-TE support & Flex Alg supp… Peter Psenak
- Re: [spring] SRV6 - SR-TE support & Flex Alg supp… Gyan Mishra