Re: [Bier] WG adoption call for draft-chen-bier-frr-02

Greg Shepherd <gjshep@gmail.com> Tue, 30 March 2021 16:47 UTC

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Reply-To: gjshep@gmail.com
From: Greg Shepherd <gjshep@gmail.com>
Date: Tue, 30 Mar 2021 09:48:25 -0700
Message-ID: <CABFReBoU2NCLNFtQ6eqhciM2DaH5UtWfoKAMM8Yok53=zC+mAA@mail.gmail.com>
To: Michael McBride <michael.mcbride@futurewei.com>
Cc: "Jeffrey (Zhaohui) Zhang" <zzhang@juniper.net>, BIER WG <bier@ietf.org>, BIER WG Chairs <bier-chairs@ietf.org>, "EXT-zhang.zheng@zte.com.cn" <zhang.zheng@zte.com.cn>, Huaimo Chen <huaimo.chen@futurewei.com>
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Subject: Re: [Bier] WG adoption call for draft-chen-bier-frr-02
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On Tue, Mar 30, 2021 at 9:28 AM Michael McBride <
michael.mcbride@futurewei.com> wrote:

> > ..contribute two authors to the merged doc effort, and have Jeffrey
> hold the pen as editor/author.
>
>
>
> Huh? All authors from both drafts will remain on the merged draft
>

Pick them now or pick them later.


> and, as much as we respect Jeffrey, he’s not an author and certainly
> doesn’t hold the pen.
>

As the assigned Editor to work with the author of both drafts, yes he will
hold the pen. If you have another 3rd party Editor to suggest, please do
so. But from the current discussion on the list, I find no one more
qualified to work with the authors of both contributing drafts.

Thanks,
Greg


> Mike
>
>
>
>
>
> All agreed?
>
>
>
> Thanks,
>
> Greg
>
> (Chairs)
>
>
>
> On Mon, Mar 29, 2021 at 7:26 PM Jeffrey (Zhaohui) Zhang <
> zzhang@juniper.net> wrote:
>
> Shouldn’t it be the other way around – expand/merge first and then adopt?
>
>
>
> In fact, the essence of draft-chen is the multiple per-nbr FRR BIFTs,
> which I don’t think should be included in the merged draft at all, for the
> following problems:
>
>
>
>    1. Scaling – we need one extra BIFT for each <neighbor, BIFT>. This
>    not only means extra memory, but also additional processing overhead
>    including downloading the tables to the forwarding plane.
>    2. If two neighbors fail simultaneously yet both can be protected by a
>    3rd neighbor, per-nbr FRR BIFTs can only give protection for one of
>    the first two neighbors. This is not an unusual situation – you could have
>    two neighbors reached by the same link or the same line card, and the
>    link/card fails.
>    3. Exactly when to switch back from a per-nbr FRR BIFT to the regular
>    BIFT?
>
>
>
> The draft says the following about #3:
>
>
>
>    In general, when the routing protocol has re-converged on the new
>
>    topology taking into account the failure of X, the BIRT is re-
>
>    computed using the updated LSDB and the BIFT is re-derived from the
>
>    BIRT.  Once the BIFT is installed ready for activation, it is
>
>    activated to forward packets with BIER headers and the FRR-BIFT for X
>
>    is de-activated.
>
>
>
> Does that mean for each computation, you need to know and mark which
> failed neighbor that it takes care of, so that when the BIFT is sent down
> to forwarding plane you can decide if currently used FRR-BIFT can be
> switched back to the main BIFT?
>
>
>
> Also consider the following:
>
>
>
>    1. At moment T you switch to FRR BIFT for nbr X
>    2. At moment T+1ms a new BIFT is calculated, which takes care of a
>    remote failure but not nbr X (nbr X is still considered up in this
>    calculation) – would you switch FRR BIFT to the newly calculated main BIFT?
>    If you don’t, the remote failure could lead to packet losses until the new
>    main BIFT is used. If you do, you only get FRR protection for nbr X for 1ms.
>
>
>
> Jeffrey
>
>
>
> *From:* BIER <bier-bounces@ietf.org> *On Behalf Of *Huaimo Chen
> *Sent:* Thursday, March 25, 2021 5:06 PM
> *To:* Tony Przygienda <tonysietf@gmail.com>om>; EXT-zhang.zheng@zte.com.cn <
> zhang.zheng@zte.com.cn>
> *Cc:* BIER WG <bier@ietf.org>rg>; BIER WG Chairs <bier-chairs@ietf.org>
> *Subject:* Re: [Bier] WG adoption call for draft-chen-bier-frr-02
>
>
>
> *[External Email. Be cautious of content]*
>
>
>
> Hi Everyone,
>
>
>
>     Michael, Steffan, Huaimo and Mike met to discuss the merge and we are
> in agreement that if draft-chen-bier-frr is adopted we will expand it to
> include a framework along with the tunnel and LFA based solutions.
>
>
>
> Best Regards,
>
> Huaimo
> ------------------------------
>
> *From:* BIER <bier-bounces@ietf.org> on behalf of Tony Przygienda <
> tonysietf@gmail.com>
> *Sent:* Tuesday, March 16, 2021 6:08 AM
> *To:* zhang.zheng <zhang.zheng@zte.com.cn>
> *Cc:* BIER WG <bier@ietf.org>rg>; BIER WG Chairs <bier-chairs@ietf.org>
> *Subject:* Re: [Bier] WG adoption call for draft-chen-bier-frr-02
>
>
>
> +1
>
>
>
> I think it's a good addition within the architecture for the case IGP is
> not used for signalling, e.g. when controller or static programming.
>
>
>
> The draft must however explain in what scenarios it is used and quote the
> according IGP drafts to guarantee loop-free behavior (well, BIER will
> tie-break loops but we'll have 1x microloop & possibly not deliver payload
> if BIER FRR is not properly computed/intsalled). With that the draft should
> also pay attention to how the function is deployed/updated network-wide if
> IGP is not present
>
>
>
> thanks
>
>
>
> -- tony
>
>
>
> On Tue, Mar 16, 2021 at 7:41 AM <zhang.zheng@zte.com.cn> wrote:
>
> A 2-week WG adoption call begins for the following draft:
>
> https://datatracker.ietf.org/doc/draft-chen-bier-frr/
> <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2Fnam11.safelinks.protection.outlook.com%2F%3Furl%3Dhttps*3A*2F*2Fdatatracker.ietf.org*2Fdoc*2Fdraft-chen-bier-frr*2F%26data%3D04*7C01*7Chuaimo.chen*40futurewei.com*7C79ac63710b47427a558d08d8e8638df2*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C1*7C637514861570555970*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C1000%26sdata%3DDiHvux0ZUYEJru10lVQ4mXvpYx3l8ujGInm7uEjjxTw*3D%26reserved%3D0__%3BJSUlJSUlJSUlJSUlJSUlJSUlJQ!!NEt6yMaO-gk!TtAnkZJhg9BEJjANzO6CusX7i7eQqvTJHdhaH0qrrPdtcykRPrUybhZeavPA3X4F%24&data=04%7C01%7Cmichael.mcbride%40futurewei.com%7C5fea93d60c124c38185908d8f3963c38%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637527173876437352%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=EQ00DXiuZoBp3fYt7j2wl%2F0y%2FHhCRKZ8v4uONv3B7c8%3D&reserved=0>
>
> Please indicate your support or objection by March 30th, 2021.
>
> Authors, please respond to the list indicating whether you are aware of
> any IPR that applies to this draft.
>
> Thanks,
>
> Sandy (As WG secretary, on behalf of Greg/Tony)
>
>
>
>
>
> Juniper Business Use Only
>
>