Re: [mpls] [spring] to progress draft-cheng-spring-mpls-path-segment

[Royi Zigler <[e-mail]>]

+1 support WG adoption.
(Sorry for late reply)

On Mon, Feb 25, 2019 at 4:32 AM Chengli (Cheng Li) <[e-mail]>
wrote:

> Hi Loa and Greg,
>
> Yes, you are right.
>
> The "B->C SubPath" in the first figure needs to be identical to the "B->C
> SubPath" in the second.
>
> Many thanks for your discussion on this, a very interesting question!
>
> Thanks,
> Cheng
>
> -----Original Message-----
> From: mpls [mailto:[e-mail]] On Behalf Of Loa Andersson
> Sent: Saturday, February 23, 2019 4:16 PM
> To: Greg Mirsky <[e-mail]>
> Cc: [e-mail]; spring <[e-mail]>; Weiqiang Cheng <
> [e-mail]>;
> [e-mail]
> Subject: Re: [mpls] [spring] to progress
> draft-cheng-spring-mpls-path-segment
>
> Greg,
>
>
>
> On 2019-02-23 12:31, Greg Mirsky wrote:
> > Hi Loa,
> > another tunnel with the Path segment from node C is, in my view, very
> > close to SPME tunnel. The Path segment from C is needed because Path
> > segment from D is not known to the node C, cannot be associated with
> > the right SR-tunnel segment, i.e., tunnel B-C. The fate sharing may be
> > achieved by using exactly the same SIDs as in the A-D tunnel for the
> > B-C segment. And GAL is still BoS on B-C tunnel. Are we getting closer?
>
> Not sure, you lose me somewhere between the "B", "C", "D", "from" and
> "another".
>
> So let me check I was talking about
>
> So the stack transporting payload from B-C looks like this:
>
>                      +------------+
>                      ~B->C SubPath~
>                      +------------+
>                      |s-PSID(B->C)|
>                      +------------+
>                      | BSID(C->D) |
>                      +------------+
>                      |e-PSID(A->D)|
>                      +------------+
>                         figure 1
>
> The "~" at the top means that there might be more than one label that can
> be popped or swapped, right?
>
> So the stack transporting GACh from B-C looks like this:
>
>                      +--------------+
>                      ~ B->C SubPath ~
>                      +--------------+
>                      |     GAL      |
>                      +--------------+
>                      |  GACh info-1 |
>                      +--------------+
>                      |  GACh info-2 |
>                      +--------------+
>                         figure 2
>
> Now my question is the "B->C SubPath" in the first figure identical to the
> "B->C SubPath" in the second figure?
> Now
> --
>
>
>
> >
> > Regards,
> > Greg
> >
> > On Fri, Feb 22, 2019 at 8:15 PM Loa Andersson <[e-mail]
> > <mailto:[e-mail]>> wrote:
> >
> >     Greg,
> >
> >     We are close, though I hope the rules are that GAL is bottom of
> stack,
> >     and that a packet with a GACh does not carry user payload.
> >
> >     I should have said that "if you want a GACg for the
> >
> >     I don't understand why we need a "new" SR tunnel, the GAL/GACh can
> >     ride with the GAL as bottom of stack with the label stack for
> >     Sub-path(B->C), right? If you put it on "another" tunnel, how do
> >     you guarantee fate sharing?
> >
> >     /Loa
> >
> >     /Loa
> >
> >     On 2019-02-23 11:55, Greg Mirsky wrote:
> >      > Hi Loa,
> >      > I think it will be similar to SPME and we'll need to have another
> >      > SR-tunnel B-C with its own Path segment allocated by node C. But
> GAL
> >      > will still be BoS.
> >      >
> >      > Regards,
> >      > Greg.
> >      >
> >      > On Fri, Feb 22, 2019 at 6:15 PM Loa Andersson <[e-mail]
> >     <mailto:[e-mail]>
> >      > <mailto:[e-mail] <mailto:[e-mail]>>> wrote:
> >      >
> >      >     Rakesh, authors,
> >      >
> >      >     I have not been thinking about this too much. But if you look
> >     at fig 2
> >      >     of draft-cheng-spring-mpls-path-segment, and you need a GACh
> >     between
> >      >     A and D, I'd say that the GAL will be at the bottom of stack.
> >      >
> >      >     What if you need the CACh for the sub-path B to C, where will
> >     the GAL
> >      >     go?
> >      >
> >      >     /Loa
> >      >
> >      >
> >      >
> >      >     On 2019-02-23 09:25, Rakesh Gandhi wrote:
> >      >      > Hi Greg,
> >      >      >
> >      >      > I am not sure if the question has been answered. I would
> think
> >      >     GAL is at
> >      >      > the bottom of the label stack.
> >      >      >
> >      >      > Thanks,
> >      >      > Rakesh
> >      >      >
> >      >      >
> >      >      > On Sat, Feb 16, 2019 at 4:24 PM Greg Mirsky
> >      >     <[e-mail] <mailto:[e-mail]>
> >     <mailto:[e-mail] <mailto:[e-mail]>>
> >      >      > <mailto:[e-mail]
> >     <mailto:[e-mail]> <mailto:[e-mail]
> >     <mailto:[e-mail]>>>> wrote:
> >      >      >
> >      >      >     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
> >      >      >     <[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>
> >      >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>>> wrote:
> >      >      >
> >      >      >         Hi Greg,____
> >      >      >
> >      >      >         Thanks a lot for your comments.____
> >      >      >
> >      >      >         My comments are in-line.____
> >      >      >
> >      >      >         __ __
> >      >      >
> >      >      >         B.R.____
> >      >      >
> >      >      >         Weiqiang Cheng____
> >      >      >
> >      >      >         __ __
> >      >      >
> >      >      >         *发件人:*Greg Mirsky [mailto:[e-mail]
> >     <mailto:gregimirsky@gmail..com>
> >      >     <mailto:[e-mail] <mailto:[e-mail]>>
> >      >      >         <mailto:gregimirsky@gmail..com
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail] <mailto:[e-mail]
> >>>]
> >      >      >         *发送时间:*2019年2月15日3:37
> >      >      >         *收件人:*Alexander Vainshtein
> >      >      >         *抄送:*spring@ietf..org <mailto:[e-mail]>
> >     <mailto:[e-mail] <mailto:[e-mail]>>
> >      >     <mailto:[e-mail] <mailto:[e-mail]>
> >     <mailto:[e-mail] <mailto:[e-mail]>>>; Stewart Bryant;
> >      >      > [e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>
> >      >      >
> >       <mailto:[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>>;
> >      >      > [e-mail] <mailto:[e-mail]> <mailto:[e-mail]
> >     <mailto:[e-mail]>> <mailto:[e-mail] <mailto:[e-mail]>
> >      >     <mailto:[e-mail] <mailto:[e-mail]>>>; 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
> >      >      >         <Alexander.Vainshtein@ecitele..com
> >      >      >         <mailto:[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>>> 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: [phone]____
> >      >      >
> >      >      >             Cell:      [phone]____
> >      >      >
> >      >      >             Email: [e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>
> >      >      >             <mailto:[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>>____
> >      >      >
> >      >      >             ____
> >      >      >
> >      >      >             -----Original Message-----
> >      >      >             From: spring <[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail] <mailto:
> [e-mail]>>
> >      >      >             <mailto:[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>>> On Behalf Of Stewart Bryant
> >      >      >             Sent: Wednesday, February 13, 2019 12:48 PM
> >      >      >             To: Loa Andersson <loa@pi..nu
> >     <mailto:[e-mail] <mailto:[e-mail]>
> >      >     <mailto:[e-mail] <mailto:[e-mail]>>>>;
> >      >      > [e-mail] <mailto:[e-mail]>
> >     <mailto:[e-mail] <mailto:[e-mail]>>
> >     <mailto:[e-mail] <mailto:[e-mail]>
> >      >     <mailto:[e-mail] <mailto:[e-mail]>>>;
> >      >      > [e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>
> >      >      >
> >       <mailto:[e-mail]
> >     <mailto:[e-mail]>
> >      >     <mailto:[e-mail]
> >     <mailto:[e-mail]>>>
> >      >      >             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____
> >      >      >
> >      >      >             ____
> >      >      >
> >      >      >
> >       ___________________________________________________
> >      >      >
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> >     <mailto:[e-mail] <mailto:[e-mail]>
> >      >     <mailto:[e-mail] <mailto:[e-mail]>>>____
> >      >      >
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> >     <http://ietf.org/mailman/listinfo/spring____>
> >      >     <http://ietf.org/mailman/listinfo/spring____>
> >      >      >
> >      >      >
> >      >      >
> >      >
> >
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> >      >
> >      >
> >      >     Loa Andersson                        email: [e-mail]
> >     <mailto:[e-mail]> <mailto:[e-mail] <mailto:[e-mail]>>
> >      >     Senior MPLS Expert
> >      >     Bronze Dragon Consulting             phone: [phone]
> >      >
> >      >
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> >
> >
> >     Loa Andersson                        email: [e-mail] <mailto:
> [e-mail]>
> >     Senior MPLS Expert
> >     Bronze Dragon Consulting             phone: [phone]
> >
> >
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>
>
> Loa Andersson                        email: [e-mail]
> Senior MPLS Expert
> Bronze Dragon Consulting             phone: [phone]
>
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-- 
Thanks,
RoyiJZ