Re: [OSPF] [spring] OSPFv2 Segment Routing Extensions ERO Extensions (would also effect OSPFv3 and IS-IS) - REPLY TO THIS ONE
<bruno.decraene@orange.com> Mon, 12 June 2017 14:05 UTC
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From: bruno.decraene@orange.com
To: "Stefano Previdi (sprevidi)" <sprevidi@cisco.com>, Rob Shakir <rjs@rob.sh>
CC: "spring@ietf.org" <spring@ietf.org>, "draft-ietf-ospf-segment-routing-extensions@ietf.org" <draft-ietf-ospf-segment-routing-extensions@ietf.org>, OSPF WG List <ospf@ietf.org>, "Peter Psenak (ppsenak)" <ppsenak@cisco.com>, "isis-wg@ietf.org" <isis-wg@ietf.org>, "idr-chairs@ietf.org" <idr-chairs@ietf.org>
Thread-Topic: [spring] [OSPF] OSPFv2 Segment Routing Extensions ERO Extensions (would also effect OSPFv3 and IS-IS) - REPLY TO THIS ONE
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Date: Mon, 12 Jun 2017 14:05:44 +0000
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Subject: Re: [OSPF] [spring] OSPFv2 Segment Routing Extensions ERO Extensions (would also effect OSPFv3 and IS-IS) - REPLY TO THIS ONE
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Hi Stefano, > From: Stefano Previdi (sprevidi) [mailto:sprevidi@cisco.com] > Sent: Monday, June 12, 2017 3:52 PM > > Hi Rob, > > sorry for the mess. I’m afraid, the problem has been poorly described. > > We’re obviously NOT questioning the use of the Binding SID and we’re NOT proposing the > removal of it. > > What we’re talking about is the set of RSVP-like/ERO-like subTLVs that have been defined in > both isis and ospf protocols and for which, apparently, nobody has found yet any use. In order to clarify, could you provide the precise list/set of those subTLVs which are proposed to be removed? for both IS-IS and OSPF. Thanks --Bruno > Can we try to shutdown the unnecessary noise and confusion ? > > Thanks. > s. > > > > On Jun 12, 2017, at 3:08 PM, Rob Shakir <rjs@rob.sh> wrote: > > > > Bruno, SPRING, > > > > I am aware of at least one implementation that makes heavy use of Binding SIDs, so I do > not think that this is something that we can remove from the protocol specification. > > It seems to me that we have a number of cases that continue to exist that make it useful to > have them specified, particularly: > > • Binding of a SID to a deeper label stack to prevent there being large label stacks > required on ingress. This is required due to limited push depth, and limited readable label > depths for hashing. > > • Re-use of some other protocol's or network's forwarding path by a device that is > imposing an SR label stack. > > There is not an alternative construct that can be used for this purpose, so we should not > remove it. > > > > In both of these cases there seems, to me, to be a use case for having the information in > the IGP in the case that an implementation computes TE paths using cSPF, having binding SID > information available to it (along with the ERO) enables it to reduce the label stack depth by > finding binding SIDs that follow the same path as the computed ERO. Without the ERO > (which might not be an RSVP-TE ERO, but I believe that it how it was first envisaged) how can > the head-end of an TE path know what path the advertised Binding SID takes? It's fine to > punt this and say "the PCE in the sky will know" - however, I believe SPRING's charter > doesn't limit the technology to only centralised computation of paths. > > > > I don't believe current demand for this is a good reason to remove it from the protocol > specification - it is still somewhat early days for folks deploying TE based on SR - where I > think the Binding SID concept is most important. > > > > r. > > > > On Mon, 12 Jun 2017 at 05:50 <bruno.decraene@orange.com> wrote: > > Hello SPRING WG, > > > > I'd like to encourage discussion on this thread. > > > > The related questions seem to be: > > - Binding SIDs: > > - Is there any implementation? > > - Is it useful? > > - Does it need to be specified? > > > > - Binding SIDs advertised in IGP: > > - Is there any implementation? > > - Is it useful? > > - Does it need to be specified? > > > > As of today, there seem to be multiple SPRING (related) document that make reference > (define/use) to the Binding SIDs. e.g. > > - architecture https://tools.ietf.org/html/draft-ietf-spring-segment-routing-11#section- > 3.5.2 > > - MPLS instantiation https://tools.ietf.org/html/draft-ietf-spring-segment-routing-mpls- > 08#section-2 > > - non-protected paths https://tools.ietf.org/html/draft-litkowski-spring-non-protected- > paths-01#section-3.3 > > - SR policies: https://tools.ietf.org/html/draft-filsfils-spring-segment-routing-policy- > 00#section-7 > > > > > > However, it also seems a priori possible to define Binding SIDs and not advertised them in > the IGP. (e.g. by keeping them local to the PCE) > > > > On a side note, if the Binding SIDs are removed from the IGP, do they need to be removed > from the BGP-LS extensions? [+IDR chairs] > > > > Thanks, > > Regards, > > --Bruno > > > > > From: OSPF [mailto:ospf-bounces@ietf.org] On Behalf Of Peter Psenak > > > Sent: Monday, June 12, 2017 10:18 AM > > > To: OSPF WG List; spring@ietf.org; isis-wg@ietf.org > > > Cc: draft-ietf-ospf-segment-routing-extensions@ietf.org > > > Subject: Re: [OSPF] OSPFv2 Segment Routing Extensions ERO Extensions (would also > effect > > > OSPFv3 and IS-IS) - REPLY TO THIS ONE > > > > > > Hi, > > > > > > I would like to get some feedback on the usage of the SID/Label Binding TLV. > > > > > > Is there any implementation that uses SID/Label Binding TLV for > > > advertising the SID/Label binding to a FEC as specified in section 6 of > > > the draft-ietf-ospf-segment-routing-extensions-16 or section 2.4 of > > > draft-ietf-isis-segment-routing-extensions-12? > > > > > > If not, do we see this as something we want to preserve in the IGP SR > > > drafts? > > > > > > ISIS uses The SID/Label Binding TLV to advertise > > > prefixes to SID/Label mappings, which is known to be supported by > > > several implementations and that piece needs to be preserved. > > > > > > thanks, > > > Peter > > > > > > On 09/06/17 19:04 , Peter Psenak wrote: > > > > Acee, > > > > > > > > my question is whether we need the whole section 6 and the SID/Label > > > > Binding Sub-TLV that it specifies. In OSPF Binding SID is not used for > > > > SRMS advertisement like in ISIS. > > > > > > > > thanks, > > > > Peter > > > > > > > > > > > > > > > > On 09/06/17 16:45 , Acee Lindem (acee) wrote: > > > >> Corrected IS-IS WG alias – Please reply to this one. > > > >> Thanks, > > > >> Acee > > > >> > > > >> From: Acee Lindem <acee@cisco.com <mailto:acee@cisco.com>> > > > >> Date: Friday, June 9, 2017 at 10:42 AM > > > >> To: OSPF WG List <ospf@ietf.org <mailto:ospf@ietf.org>>, > > > >> "spring@ietf.org <mailto:spring@ietf.org>" <spring@ietf.org > > > >> <mailto:spring@ietf.org>>, "isis@ietf.org <mailto:isis@ietf.org>" > > > >> <isis@ietf.org <mailto:isis@ietf.org>> > > > >> Cc: "draft-ietf-ospf-segment-routing-extensions@ietf.org > > > >> <mailto:draft-ietf-ospf-segment-routing-extensions@ietf.org>" > > > >> <draft-ietf-ospf-segment-routing-extensions@ietf.org > > > >> <mailto:draft-ietf-ospf-segment-routing-extensions@ietf.org>> > > > >> Subject: OSPFv2 Segment Routing Extensions ERO Extensions (would also > > > >> effect OSPFv3 and IS-IS) > > > >> > > > >> Hi OSPF, ISIS, and SPRING WGs, > > > >> > > > >> As part of the Alia’s AD review, she uncovered the fact that the ERO > > > >> extensions in 6.1 and 6.2 are specified as far as encoding but are > > > >> not specified as far as usage in any IGP or SPRING document. As > > > >> document shepherd, my proposal is that they simply be removed since > > > >> they were incorporated as part of a draft merge and it appears that > > > >> no one has implemented them (other than parsing). We could also > > > >> deprecate types (4-8) in the OSPFv2 Extended Prefix LSA Sub-TLV > > > >> registry to delay usage of these code points for some time (or > > > >> indefinitely ;^). > > > >> > > > >> Thanks, > > > >> Acee > > > >> > > > > > > > > . > > > > > > > > > > _______________________________________________ > > > OSPF mailing list > > > OSPF@ietf.org > > > https://www.ietf.org/mailman/listinfo/ospf > > > > > ______________________________________________________________________ > ___________________________________________________ > > > > Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou > privilegiees et ne doivent donc > > pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par > erreur, veuillez le signaler > > a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant > susceptibles d'alteration, > > Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. > > > > This message and its attachments may contain confidential or privileged information that > may be protected by law; > > they should not be distributed, used or copied without authorisation. > > If you have received this email in error, please notify the sender and delete this message > and its attachments. > > As emails may be altered, Orange is not liable for messages that have been modified, > changed or falsified. > > Thank you. > > > > _______________________________________________ > > spring mailing list > > spring@ietf.org > > https://www.ietf.org/mailman/listinfo/spring > > _______________________________________________ > > spring mailing list > > spring@ietf.org > > https://www.ietf.org/mailman/listinfo/spring _________________________________________________________________________________________________________________________ Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration, Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. This message and its attachments may contain confidential or privileged information that may be protected by law; they should not be distributed, used or copied without authorisation. If you have received this email in error, please notify the sender and delete this message and its attachments. As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified. Thank you.
- Re: [OSPF] OSPFv2 Segment Routing Extensions ERO … Acee Lindem (acee)
- Re: [OSPF] OSPFv2 Segment Routing Extensions ERO … Peter Psenak
- Re: [OSPF] OSPFv2 Segment Routing Extensions ERO … Acee Lindem (acee)
- Re: [OSPF] OSPFv2 Segment Routing Extensions ERO … Peter Psenak
- Re: [OSPF] OSPFv2 Segment Routing Extensions ERO … bruno.decraene
- Re: [OSPF] [spring] OSPFv2 Segment Routing Extens… Acee Lindem (acee)
- Re: [OSPF] [spring] OSPFv2 Segment Routing Extens… Jeff Tantsura
- Re: [OSPF] [spring] OSPFv2 Segment Routing Extens… Rob Shakir
- Re: [OSPF] OSPFv2 Segment Routing Extensions ERO … bruno.decraene
- Re: [OSPF] [spring] OSPFv2 Segment Routing Extens… Stefano Previdi (sprevidi)
- Re: [OSPF] OSPFv2 Segment Routing Extensions ERO … Acee Lindem (acee)
- Re: [OSPF] [spring] OSPFv2 Segment Routing Extens… bruno.decraene
- Re: [OSPF] [spring] OSPFv2 Segment Routing Extens… Peter Psenak
- Re: [OSPF] [spring] OSPFv2 Segment Routing Extens… Stefano Previdi (sprevidi)