Re: [Bier] A comment about draft-xzlnp-bier-ioam

[Tianran Zhou <[e-mail]>]

Hi Greg,

Even the overlay, there are at least three solutions.
The GFH, BIER-IOAM, multicast-telemetry.
BIER is rare implemented.
Are we going to standardize so many solutions?

Best,
Tianran

From: Greg Mirsky [mailto:[e-mail]]
Sent: Tuesday, March 22, 2022 3:51 AM
To: Tianran Zhou <[e-mail]>
Cc: xiao.min2 <[e-mail]>; zzhang <[e-mail]>; bier <[e-mail]>
Subject: Re: [Bier] A comment about draft-xzlnp-bier-ioam

Hi Tianran,
thank you for the question. I think that it is more related to the operational motivation of how to use on-path telemetry mechanisms, e.g., IOAM. If it is applied in the underlay network (MPLS or IPv6), an operator can monitor the performance of directly connected BIER nodes and underlay tunnels connecting them. To gain visibility into all of the multicast distribution from the BFIR to all BFERs each BFR must act as IOAM encapsulating and decapsulating node. On the other hand, applying IOAM it the BIER layer will provide telemetry information from only BFRs. I think that both are useful and the choice should be given to operators.

Regards,
Greg

On Mon, Mar 21, 2022 at 8:33 AM Tianran Zhou <zhoutianran=[e-mail]<mailto:[e-mail]>> wrote:
Emmm, then my question is why we need the same function at different layers?
Can we just choose one?

Tianran



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发件人： xiao.min2<[e-mail]<mailto:[e-mail]>>
收件人： Tianran Zhou<[e-mail]<mailto:[e-mail]>>
抄送： zzhang<[e-mail]<mailto:[e-mail]>>;bier<[e-mail]<mailto:[e-mail]>>
主题： Re:[Bier] A comment about draft-xzlnp-bier-ioam
时间： 2022-03-21 09:31:05

Hi Tianran,

Generally speaking that's because they (IPv6, MPLS, BIER) are different layers, as indicated in Jeffrey's GDF draft.
Specifically, my personal criteria is that whether this layer would affect packet forwarding, e.g., SFC NSH layer would, so there is an adopted NSH IOAM draft (draft-ietf-sfc-ioam-nsh), BIER layer is similar. For other layers that wouldn't affect packet forwarding, e.g., Geneve layer, the advantage to have IOAM over it is not clear to me.

Best Regards,
Xiao Min

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发件人：TianranZhou
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抄送人：bier;
日 期 ：2022年03月19日 21:58
主 题 ：Re: [Bier] A comment about draft-xzlnp-bier-ioam
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I have concern about so many options for the same functionality.
Especially, there’s already IOAM encapsulation for MPLS and IPv6. Why we need another encapsulation in BIER layer?
As far as I understand, BIER will always be used with MPLS or IPv6.
Tianran
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发件人： xiao.min2<[e-mail]<mailto:[e-mail]>>
收件人： zzhang=40juniper.net<http://40juniper.net><zzhang=[e-mail]<mailto:[e-mail]>>
抄送： bier<[e-mail]<mailto:[e-mail]>>
主题： Re: [Bier] A comment about draft-xzlnp-bier-ioam
时间： 2022-03-19 14:33:01
Hi Jeffrey,
Thank you for bringing it up to our attention.
I do agree your GDF draft provides a third option on how to encapsulate IOAM over BIER, which is different from the two options already described and compared in this BIER-IOAM draft.
To my understanding, the initial and main motivation to introduce GDF is to provide a fragmentation header for MPLS/BIER etc, just like IPv6 FH.
With that in mind, one possible way to push this "Encapsulating IOAM in BIER" work forward is to add the third option into BIER-IOAM draft for comparison, that makes it focused and easy to follow.
What's your opinion?
Best Regards,
Xiao Min
------------------原始邮件------------------
发件人：Jeffrey(Zhaohui)Zhang
收件人：'[e-mail]<mailto:[e-mail]>';[e-mail]<mailto:[e-mail]>;
日 期 ：2022年03月18日 20:56
主 题 ：[Bier] A comment about draft-xzlnp-bier-ioam
Hi,
For IOAM data in BIER, I want to point out that we should use a generic header format that can be used for BIER/MPLS/IPv6. The same extension mechanism can be used for other purposes like fragmentation/security, etc.
This was discussed in  https://www.ietf.org/archive/id/draft-zzhang-intarea-generic-delivery-functions-02.txt, and was mentioned in slide #6 of  https://datatracker.ietf.org/meeting/112/materials/slides-112-bier-03-bier-slicing-and-differentiation-00 in IETF112 BIER session.
Thanks.
Jeffrey
Juniper Business Use Only
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