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.
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? 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? 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. Kind regards Gyan On Tue, Mar 31, 2020 at 5:15 AM Ketan Talaulikar (ketant) <ket...@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-boun...@ietf.org> On Behalf Of Peter Psenak > Sent: 31 March 2020 13:42 > To: Gyan Mishra <hayabusa...@gmail.com>; SPRING WG <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.mis...@verizon.com <mailto:gyan.s.mis...@verizon.com> > > > > > > > > _______________________________________________ > spring mailing list > 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.mis...@verizon.com
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