Re: [Lsr] LSR WG Adoption Call for "Algorithm Related IGP-Adjacency SID Advertisement"

[[e-mail]]

Hi Jie,

Please see inline [PSF]


------------------原始邮件------------------
发件人：Dongjie(Jimmy)
收件人：彭少富10053815;
抄送人：[e-mail];[e-mail];
日 期 ：2021年05月31日 17:35
主 题 ：Re: [Lsr] LSR WG Adoption Call for "Algorithm Related IGP-Adjacency SID Advertisement"
Hi PSF,
Please see inline:
> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]]
> Sent: Monday, May 31, 2021 9:41 AM
> To: Dongjie (Jimmy) <[e-mail]>
> Cc: [e-mail]; [e-mail]
> Subject: Re:[Lsr] LSR WG Adoption Call for "Algorithm Related IGP-Adjacency
> SID Advertisement"
>
> Hi Jie,
>
> Thanks.
> Again, in this document we describe local behavior per algorithm thanks to
> adj-sid per algo, but not describe any resource reservatoin extensions to
> flex-algo. the later can be discussed in another thread.
Then it is reasonable to remove the text about use case 1, 2 and the operations in section 5 which are related to per flex-algo resource reservation or traffic treatment over the same link, as you said they are local behaviors thus do not require  interoperability.

[PSF] I'm afraid we can't come to the conclusion that some description of local behavior that is  beneficial to understand the integrity of the whole scheme must not be contained in the document. It does not violate any iron law. The significance of their existence is to show that the local behavior related to the algorithm is possible, so the use of flex algo alone can be competent for some scenarios (e.g, network slicing).  I think the section of use case is open, and ajdacency backup use case is not the only case.
> IMO the local behavior can be any local policies, such as local repair path, local
> queue, local priority for entry installation, etc. Adj-sid per algo provides the
> basis for these local behavior. It is useful to describe how adj-sid per algo can
> satisfy these usecases, also to facilitate readers to understand its use.
Local repair is different from the other cases you mentioned. Local repair results in the change of the path and the SID list, which is visible to the network.

[PSF] I don't believe local repair path is visible to other nodes of the network. If you means that show the state of local repair path, you can also show the state of local queue. 

 In addition, the computation of local repair path is based on the Flex-Algo constraints defined by the FAD. In contrast, the local queue or priority information is not reflected in the FAD.

[PSF] Agree, you can also find that local queue is different with local priority. This difference is not our focus, we focus on the possibility of local policy per algo on nodes.
Before introducing the local queue and priority use cases to this draft, it is necessary to understand whether such local information need to be included in the FAD or not, and propose relevant Flex-Algo extensions for it, otherwise IMO they are local information and behaviors which are NOT related to Flex-Algo.

[PSF] See the first untenable conclusion.
Best regards,
Jie
> You are very concerned about the extension of resource reservation. Although
> it is not related to this document and should be discussed in another thread, I
> will try to answer it in your previous email.
>
> Regards,
> PSF
>
>
>
>
> ------------------原始邮件------------------
> 发件人：Dongjie(Jimmy)
> 收件人：彭少富10053815;
> 抄送人：[e-mail];[e-mail];
> 日 期 ：2021年05月28日 14:24
> 主 题 ：RE: Re:[Lsr] LSR WG Adoption Call for "Algorithm Related
> IGP-Adjacency SID Advertisement"
> Hi PSF,
> Thanks for your pointer to another document which defines the encodings of
> per-Algo TE link attributes.
> But my comments are related to the text in section 3 and 5 of this document,
> which describes new use cases and operation of Flex-Algo with per Flex-Algo
> resource reservation or per Flex-Algo QoS policy on the same link. These require
> extensions to the function of Flex-Algo, which IMO needs to be discussed and
> compared with other alternative mechanisms. And as you indicated, there are
> related encoding extensions proposed in other document, thus it may not be
> just a local behavior.
> So could you reply to the comments in my previous mail?
> Best regards,
> Jie
> > -----Original Message-----
> > From: [e-mail] [mailto:[e-mail]]
> > Sent: Friday, May 28, 2021 12:00 PM
> > To: Dongjie (Jimmy) <[e-mail]>
> > Cc: [e-mail]; [e-mail]
> > Subject: Re:[Lsr] LSR WG Adoption Call for "Algorithm Related
> > IGP-Adjacency SID Advertisement"
> >
> > Hi Jie,
> >
> > Thanks for your comments.
> >
> > In this document, there are not any extensions to describe resource
> > reservation per algo. Are you aiming at another draft
> > (https://datatracker.ietf.org/doc/draft-cp-lsr-fa-aware-te/) ?  Please
> > find out what you are talking about first.
> > Adj-SID per algo can distinguish traffic behavior in local. You are
> > welcome to add more usecases based on section 3.
> >
> > Regards,
> > PSF
> >
> >
> > ------------------原始邮件------------------
> > 发件人：Dongjie(Jimmy)
> > 收件人：Christian Hopps;[e-mail];
> > 日 期 ：2021年05月28日 11:40
> > 主 题 ：Re: [Lsr] LSR WG Adoption Call for "Algorithm Related
> > IGP-Adjacency SID Advertisement"
> > Hi,
> > I don't support the adoption of this document.
> > It seems this document aims to introduce per Flex-Algo Adj-SID to
> > SR-MPLS, its typical use case is to provide protection path with
> > Flex-Algo constraints for Adj-SID of a particular Flex-Algo, which is described
> in the case 3 of section 3.
> > However, section 3 and section 5 shows that it also aims to introduce
> > further changes to the usage and operation of Flex-Algo, which is to
> > provide resource reservation based on Flex-Algo. IMO these changes to
> > Flex-Algo deserves further discussion and is not only related to the per
> Flex-Algo Adj-SID extension.
> > Here are some comments about this change to Flex-Algo:
> > 1. Flex-Algo defines the constraints for path computation in a
> > distributed manner, it is not for resource reservation.
> > 2. Reserving resources for each Flex-Algo on a link does not make
> > sense. The correlation between Flex-Algo and the network links is
> > based on administrative groups (color), and the color of the link may
> > or may not be included in the Flex-Algo definition. To follow the
> > color based link correlation, a more practical approach would be to
> > use Flex-Algo with L2 bundle as defined in
> > draft-zhu-lsr-isis-sr-vtn-flexalgo, which uses color to correlate the
> > L3 link and the L2 member link to a Flex-Algo, this avoids the extension for
> per-FlexAlgo resource reservation.
> > 3. The Flex-Algo link TE attributes are advertised using ASLA, the TE
> > attributes are shared by all Flex-Algos which include the link
> > according to the FAD, and based on previous discussion, it seems there
> > is no intention to introduce per Flex-Algo ID link attributes.
> > Best regards,
> > Jie
> > > -----Original Message-----
> > > From: Lsr [mailto:[e-mail]] On Behalf Of Christian Hopps
> > > Sent: Thursday, May 27, 2021 4:57 AM
> > > To: [e-mail]
> > > Cc: [e-mail]
> > > Subject: [Lsr] LSR WG Adoption Call for "Algorithm Related
> > > IGP-Adjacency SID Advertisement"
> > >
> > >
> > > Hi Folks,
> > >
> > > This begins a 2 week WG Adoption Call for the following draft:
> > >
> > > https://datatracker.ietf.org/doc/draft-peng-lsr-algorithm-related-ad
> > > ja
> > > cency-sid
> > > /
> > >
> > > Please indicate your support or objections by June 9th, 2021
> > >
> > > Authors, please respond to the list indicating whether you are aware
> > > of any IPR that applies to this draft.
> > >
> > > Thanks,
> > > Acee and Chris.
> > >
> > > _______________________________________________
> > > Lsr mailing list
> > > [e-mail]
> > > https://www.ietf.org/mailman/listinfo/lsr
> > _______________________________________________
> > Lsr mailing list
> > [e-mail]
> > https://www.ietf.org/mailman/listinfo/lsr
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