Hi Weiqiang Cheng, thank you for your expedient response to my questions. The document states that one of the use cases for the Path segment is to be used as a performance, packet loss and/or delay, measurement session identifier. I think that RFC 6374 is the most suitable for PM OAM in SR-MPLS environment. Of course, the type of the encapsulated message can be identified using the destination UDP port number with IP/UDP encapsulation. But another option is to use G-ACh encapsulation. That would require the use of GAL. And that is how I've arrived at my original question (I should have explained it better, my apologies):
How the Path segment and GAL are placed relative to each other in the SR-MPLS label stack? Regards, Greg On Fri, Feb 15, 2019 at 4:40 PM Weiqiang Cheng < [email protected]> wrote: > Hi Greg, > > Thanks a lot for your comments. > > My comments are in-line. > > > > B.R. > > Weiqiang Cheng > > > > *发件人:* Greg Mirsky [mailto:[email protected]] > *发送时间:* 2019年2月15日 3:37 > *收件人:* Alexander Vainshtein > *抄送:* [email protected]; Stewart Bryant; > [email protected]; [email protected]; Loa > Andersson > *主题:* Re: [spring] to progress draft-cheng-spring-mpls-path-segment > > > > Dear All, > > I concur with all what has been said in support of the adoption of this > draft by SPRING WG. The document is well-written, addresses the real > problem in SR-MPLS, and the proposed solution is technically viable. > > My comments and questions are entirely for further discussion: > > - would the draft be expanded to demonstrate how "the Path Segment may > be used to identify an SR-MPLS Policy, its Candidate-Path (CP) or a SID > List (SL)"? > > [Weiqiang] Yes, It is necessary and we will add some text to demonstrate > this in the future version. > > - as many use cases for the Path Segment are related to OAM > operations, it would be helpful to expand on the use of GAL and the Path > Segment. > > [Weiqiang] It is always helpful to have more use cases. However, > The GAL is used today in MPLS-TP LSPs to flag the G-Ach and is used for OAM > packets only while the Path segment is used for data packets for the each > traffic flow. It is a little bit different. > > Regards, > > Greg > > > > On Thu, Feb 14, 2019 at 1:12 AM Alexander Vainshtein < > [email protected]> wrote: > > +1. > > > > I have been following this draft from its -00 revision. The current > revision has resolved most of the issues I (and others) have been raised > (e.g., elimination of excessive options). > > > > From my POV, in its current state the draft meets two basic requirements > for the WG adoption: > > 1. It addresses a real and relevant problem, namely the MPLS Flow > Identification problem discussed in general in RFC 8372 > <https://tools.ietf.org/html/rfc8372> and scoped to SR-MPLS LSPs in this > draft. Specifics of SR-MPLS include the need to provide end-to-end liveness > check that is one of the requirements explicitly specified in Section 2 of RFC > 8355 <https://tools.ietf.org/html/rfc8355>. > > 2. It provides a reasonable (from my POV) approach to solution of > this problem. > > > > I also concur with Stewart’s comment about strong similarity between the > approach taken in this draft for SR-MPLS and generic work in progress on > synonymous flow labels > <https://tools.ietf.org/html/draft-ietf-mpls-sfl-framework-04> that has > been already adopted as a MPLS WG item. To me this is yet another > indication that the draft should be adopted. > > > > My 2c, > > Sasha > > > > Office: +972-39266302 > > Cell: +972-549266302 > > Email: [email protected] > > > > -----Original Message----- > From: spring <[email protected]> On Behalf Of Stewart Bryant > Sent: Wednesday, February 13, 2019 12:48 PM > To: Loa Andersson <[email protected] <[email protected]>>; [email protected]; > [email protected] > Subject: Re: [spring] to progress draft-cheng-spring-mpls-path-segment > > > > I have just read the draft and agree that it should be adopted by the WG. > It solves an important problem in instrumenting and protecting an SR path.. > > > > It should be noted that we needed to do something very similar in > mainstream MPLS via the synonymous label work which is already adopted. > > However SL did not address the SR case. We therefore need this path label > work to be progressed. > > > > - Stewart > > > > On 10/02/2019 08:11, Loa Andersson wrote: > > > Working Group, > > > > > > I have reviewed draft-cheng-spring-mpls-path-segment and as far as I > > > can see, it is ready for wg adoption. > > > > > > There were some comments in Bangkok, but due to the many collisions > > > between working groups at that meeting I couldn't attend the SPRING > > > f2f. > > > > > > The minutes are not clear, but as far as I understand, there is > > > nothing that can't be resolved in the wg process. > > > > > > /Loa > > > > _______________________________________________ > > spring mailing list > > [email protected] > > https://www..ietf.org/mailman/listinfo/spring > > > ___________________________________________________________________________ > > This e-mail message is intended for the recipient only and contains > information which is > CONFIDENTIAL and which may be proprietary to ECI Telecom. If you have > received this > transmission in error, please inform us by e-mail, phone or fax, and then > delete the original > and all copies thereof. > ___________________________________________________________________________ > > _______________________________________________ > spring mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/spring > >
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