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=
40huawei.com@dmarc.ietf.org> 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<xiao.min2@zte.com.cn>
> *收件人： *Tianran Zhou<zhoutianran@huawei.com>
> *抄送： *zzhang<zzhang@juniper.net>;bier<bier@ietf.org>
> *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
>
> ------------------原始邮件------------------
> 发件人：TianranZhou
> 收件人：肖敏10093570;zzhang=40juniper.net;
> 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
> Sent from WeLink
> 发件人： xiao.min2<xiao.min2@zte.com.cn>
> 收件人： zzhang=40juniper.net<zzhang=40juniper.net@dmarc.ietf.org>
> 抄送： bier<bier@ietf.org>
> 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：'bier@ietf.org';draft-xzlnp-bier-ioam@ietf.org;
> 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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