[Isis-wg] 答复: 答复: WG Last Call for draft-ietf-isis-segment-routing-msd-07

Xuxiaohu <xuxiaohu@huawei.com> Fri, 22 December 2017 00:42 UTC

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From: Xuxiaohu <xuxiaohu@huawei.com>
To: Jeff Tantsura <jefftant.ietf@gmail.com>, "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>, "Ketan Talaulikar (ketant)" <ketant@cisco.com>, Christian Hopps <chopps@chopps.org>, "isis-wg@ietf.org" <isis-wg@ietf.org>
CC: "isis-ads@ietf.org" <isis-ads@ietf.org>, "draft-ietf-isis-segment-routing-msd@ietf.org" <draft-ietf-isis-segment-routing-msd@ietf.org>
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Date: Fri, 22 Dec 2017 00:42:03 +0000
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Jeff,

IMHO, the MSD or the MSD(type 1) just indicates a certain label imposition capability which should be signaling-agnostic. More specially, the MSD or MSD(type1) capability could be signaled via IGP, BGP or PCEP. 

If the semantic of MSD (type 1) as defined in your IGP-MSD draft equals the semantics of MSD as defined in PCEP-SR draft, I believe it'd better to iron out such terminology inconsistency ASAP.

Best regards,
Xiaohu

> -----邮件原件-----
> 发件人: Jeff Tantsura [mailto:jefftant.ietf@gmail.com]
> 发送时间: 2017年12月22日 5:22
> 收件人: Xuxiaohu; Les Ginsberg (ginsberg); Ketan Talaulikar (ketant); Christian
> Hopps; isis-wg@ietf.org
> 抄送: isis-ads@ietf.org; draft-ietf-isis-segment-routing-msd@ietf.org
> 主题: Re: 答复: [Isis-wg] WG Last Call for draft-ietf-isis-segment-routing-msd-07
> 
> Xuxiaohu,
> 
> To clarify:
> The concept had been developed in both, in parallel, however PCEP
> implementation is limited (node only, PCC in question has to have PCEP sessions
> with the PCE), and this is clearly stated in the draft – if MSD is known from both
> sources (PCEP and IGP/BGP-LS) the later takes precedence. IGP drafts are the
> source of truth when it comes to semantics definitions.



> Personally, I don’t see any confusion wrt name, all drafts have been around for
> quite some time, reviewed by many people, presented in academia and
> networking events, noone was ever confused…
> 
> I’m not sure about value of your proposal either, and I’d leave the decision
> what to use to people who are the consumers of the technology, those who are
> going to implement it (at least 3 MSD implementations are on their ways).
> 
> As the last point – we are not “considering” expanding, the draft is clear about
> the future extensions to come and encoding is done in a way to facilitate such
> extensions.
> This is the working group last call for the draft, not a discussion whether we
> should proceed with the technology:
> If you see any technical problems with the solution proposed – I’d be the first
> to listen to you and address them!
> 
> Happy holidays!
> 
> Cheers,
> Jeff
> 
> -----Original Message-----
> From: Xuxiaohu <xuxiaohu@huawei.com>
> Date: Wednesday, December 20, 2017 at 18:40
> To: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>om>, "Ketan Talaulikar (ketant)"
> <ketant@cisco.com>om>, Christian Hopps <chopps@chopps.org>rg>, "isis-wg@ietf.org"
> <isis-wg@ietf.org>
> Cc: "isis-ads@ietf.org" <isis-ads@ietf.org>rg>,
> "draft-ietf-isis-segment-routing-msd@ietf.org"
> <draft-ietf-isis-segment-routing-msd@ietf.org>
> Subject: 答复: [Isis-wg] WG Last Call for draft-ietf-isis-segment-routing-msd-07
> Resent-From: <alias-bounces@ietf.org>
> Resent-To: <jefftant.ietf@gmail.com>om>, <uma.chunduri@huawei.com>om>,
> <aldrin.ietf@gmail.com>om>, <ginsberg@cisco.com>
> Resent-Date: Wed, 20 Dec 2017 18:40:16 -0800 (PST)
> 
>     Hi Les,
> 
>     If I understand it correctly, the MSD concept was originated from
> (https://tools.ietf.org/html/draft-ietf-pce-segment-routing-11#page-7) as
> described below:
> 
>     "The "Maximum SID Depth" (1
>        octet) field (MSD) specifies the maximum number of SIDs (MPLS label
>        stack depth in the context of this document) that a PCC is capable of
>        imposing on a packet."
> 
>     Before considering expanding the semantics of the MSD concept as defined
> in the above PCE-SR draft, how about first considering renaming the capability
> of imposing the maximum number of labels so as to eliminate possible
> confusions, e.g., Writable Label-stack Depth (WLD) as opposed to the Readable
> Label-stack Depth (RLD) as defined in
> (https://tools.ietf.org/html/draft-ietf-ospf-mpls-elc) and
> (https://tools.ietf.org/html/draft-ietf-isis-mpls-elc) ?
> 
>     Best regards,
>     Xiaohu
> 
>     > -----邮件原件-----
>     > 发件人: Isis-wg [mailto:isis-wg-bounces@ietf.org] 代表 Les Ginsberg
> (ginsberg)
>     > 发送时间: 2017年12月21日 4:02
>     > 收件人: Ketan Talaulikar (ketant); Christian Hopps; isis-wg@ietf.org
>     > 抄送: isis-ads@ietf.org; draft-ietf-isis-segment-routing-msd@ietf.org
>     > 主题: Re: [Isis-wg] WG Last Call for draft-ietf-isis-segment-routing-msd-07
>     >
>     > Ketan -
>     >
>     > Thanx for the comments.
>     > I think we do want to allow MSD support for values other than imposition
>     > values. We will revise the text so we are not restricted to only imposition
> cases.
>     >
>     >   Les
>     >
>     >
>     > > -----Original Message-----
>     > > From: Ketan Talaulikar (ketant)
>     > > Sent: Wednesday, December 20, 2017 1:51 AM
>     > > To: Christian Hopps <chopps@chopps.org>rg>; isis-wg@ietf.org
>     > > Cc: isis-ads@ietf.org; draft-ietf-isis-segment-routing-msd@ietf.org
>     > > Subject: RE: [Isis-wg] WG Last Call for
>     > > draft-ietf-isis-segment-routing-msd-07
>     > >
>     > > Hello,
>     > >
>     > > I support this document and would like to ask the authors and WG to
>     > > consider if we can expand the scope of this draft to not just
>     > > "imposition" of the SID stack but also other similar limits related to
> other
>     > actions (e.g.
>     > > reading, processing, etc.). With Segment Routing, we are coming across
>     > > various actions that nodes need to do with the SID stack for different
>     > > purposes and IMHO it would be useful to extend the MSD ability to
>     > > cover those as they arise.
>     > >
>     > > Thanks,
>     > > Ketan
>     > >
>     > > -----Original Message-----
>     > > From: Isis-wg [mailto:isis-wg-bounces@ietf.org] On Behalf Of Christian
>     > > Hopps
>     > > Sent: 20 December 2017 14:03
>     > > To: isis-wg@ietf.org
>     > > Cc: isis-ads@ietf.org; draft-ietf-isis-segment-routing-msd@ietf.org
>     > > Subject: [Isis-wg] WG Last Call for
>     > > draft-ietf-isis-segment-routing-msd-07
>     > >
>     > >
>     > > The authors have asked for and we are starting a WG Last Call on
>     > >
>     > >  https://datatracker.ietf.org/doc/draft-ietf-isis-segment-routing-msd/
>     > >
>     > > which will last an extended 4 weeks to allow for year-end PTO patterns.
>     > >
>     > > An IPR statement exists:
>     > >
>     > >
>     > > https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-is
>     > > is-
>     > > segment-routing-msd
>     > >
>     > > Authors please reply to the list indicating whether you are aware of
>     > > any
>     > > *new* IPR.
>     > >
>     > > Thanks,
>     > > Chris.
>     > >
>     > > _______________________________________________
>     > > Isis-wg mailing list
>     > > Isis-wg@ietf.org
>     > > https://www.ietf.org/mailman/listinfo/isis-wg
>     >
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