Re: [mpls] Concerns about ISD

Hi Tianran

Comment on-line

On Fri, Apr 29, 2022 at 12:05 PM John E Drake <jdrake=
40juniper.net@dmarc.ietf.org> wrote:

> Comment inline
>
> Sent from my iPhone
>
> On Apr 29, 2022, at 11:17 AM, Tianran Zhou <zhoutianran@huawei.com> wrote:
>
> 
>
> [External Email. Be cautious of content]
>
> Hi,
> Comments inline.
>
> Tianran
>
> >
> > Hi John,
> >
> >  If we want to reuse this for consistent design (easy for interop), how
> do you
> > want to encode it to ISD?
> >
> > [JD]  That's up to a given solution to propose, but probably two LSEs
> >
> > ZTR> It would be interesting to know your proposal.
>
> [JD]  As I said, the size of an NRP ID needs to be decided and any MNA
> solution needs propose how it is to be
> encoded
>
> ZTR> Ok, so any solution need to demonstrate how it works.
>
> >
> >
> > 2. If we really worry about the MSD of SR, why not use BSID as a direct
> way to
> > reduce the stack?
> >
> > [JD]  Because it can't be mandated
> >
> > ZTR> I am sorry, I do not understand why BSID is not applicable. What's
> the "
> > mandated " mean here?
>
> [JD]  MNA cannot require the use of BSIDs
>
> ZTR> Is this an agreed requirement? In the requirement draft? I still
> can’t understand. On one hand, you worry about low stack depth. On the
> other hand, you don’t want to use an easy way to solve this problem.
>
>     Gyan>. BSID is not a requirement for SR architecture per RFC 8402
 section 5, however is required for SR-TE.  All implementations of SR-MPLS
requires SR-TE for steering, however not mandated.  BGP SRv6 services TLV
encoding SRv6-BE w/o SRH or SRv6-TE w/ SRH TEA can function without SR
Policy.  So per John why BSID is not made a requirement for SR architecture
to give flexibility for implementation as well as to operators is my
understanding.  BSID does help with scalability and MSD and so most
operators deploying SR would take advantage of SR-TE BSID for SID list
compression.

> [JD]  I don’t think it’s realistic to tell a network operator that they
> have to deploy BSID in order to deploy MNA.  Also, I don’t think it’s a
> good solution became a label stack of BSIDs may still be too large and the
> node advertising the BSID is going to expand the the label stack with the
> path SIDS so the nodes on the path will have to deal with a large label
> stack.
>

> >
> > Tianran
>
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*Gyan Mishra*

*Network Solutions A**rchitect *

*Email gyan.s.mishra@verizon.com <gyan.s.mishra@verizon.com>*

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