Re: [Bier] WGLC: draft-ietf-bier-php

[Greg Mirsky <[e-mail]>]

Hi Jeffrey,
thank you for your kind consideration of my comments and addressing them.

Regards,
Greg

On Mon, Aug 24, 2020 at 10:50 AM Jeffrey (Zhaohui) Zhang <[e-mail]>
wrote:

> Hi Loa, Greg,
>
>
>
> I’ve submitted -06 to take care of your comments.
>
>
>
> Thanks.
>
> Jeffrey
>
>
>
> Juniper Business Use Only
>
> *From:* BIER <[e-mail]> *On Behalf Of * Jeffrey (Zhaohui)
> Zhang
> *Sent:* Monday, August 24, 2020 11:16 AM
> *To:* Loa Andersson <[e-mail]>; Gyan Mishra <[e-mail]>;
> Mankamana Mishra (mankamis) <mankamis=[e-mail]>
> *Cc:* IJsbrand Wijnands (iwijnand) <iwijnand=[e-mail]>;
> Greg Shepherd <[e-mail]>; [e-mail]
> *Subject:* Re: [Bier] WGLC: draft-ietf-bier-php
>
>
>
> *[External Email. Be cautious of content]*
>
>
>
> Hi Loa,
>
>
>
> Please see zzh> below.
>
>
>
> -----Original Message-----
> From: BIER <[e-mail]> On Behalf Of Loa Andersson
> Sent: Saturday, August 22, 2020 1:57 AM
> To: Gyan Mishra <[e-mail]>; Mankamana Mishra (mankamis) <
> mankamis=[e-mail]>
> Cc: IJsbrand Wijnands (iwijnand) <iwijnand=[e-mail]>;
> Greg Shepherd <[e-mail]>; [e-mail]
> Subject: Re: [Bier] WGLC: draft-ietf-bier-php
>
>
>
> [External Email. Be cautious of content]
>
>
>
>
>
> Working Group,
>
>
>
> I've had time to read the draft a bit more in detail.
>
>
>
> I'm convinced that this will work, and support progressing the draft.
>
>
>
> I still think there are some minor description details that could be
> improved.
>
>
>
> The draft says:
>
>
>
>     One way to solve this problem is to use Penultimate Hop Popping (PHP)
>
>     so that the upstream BFR can pop the BIER header and send the payload
>
>     "natively" (note that the upstream BFR can be connected directly or
>
>     indirectly via any type of tunnel to the PE).  This is similar to
>
>     Multi-Protocol Label Switching (MPLS) PHP though it is the BIER
>
>     header that is popped.
>
>
>
> This indicate that this is a "per node" decision, while in MPLS it is a
> per LSP decision.
>
>
>
> Zzh> It’s a per node decision for all traffic to a particular “BFER” who
> does not really support BIER forwarding. PHP is not used when the BFERs do
> support BIER.
>
>
>
> I would think that it is possible for one node to be the penultimate node
> for some traffic but not for other traffic, even though the traffic is sent
> to the same node, which can be both ultimate node, pen-ultimate node or
> transit node.
>
>
>
>       +-------+              +-------+          +-------+
>
>       |       |              |       |          |       |
>
> -a,b-+   A   +-----a',b-----+   B   +----a'----+  CPE1 |
>
>       |       |              |       |          |       |
>
>       +-------+              +---+---+          +-------+
>
>                                  |
>
>                                  b'
>
>                                  |
>
>                              +---+---+          +-------+
>
>                              |       |          |       |
>
>                              +   C   +----b'----+  CPE2 |
>
>                              |       |          |       |
>
>                              +---+---+          +-------+
>
>
>
>
>
> Two streams comes in to A from the left (a and b).
>
>
>
> A is the penultimate node for traffic to to CPE1 (a) so the BIER header is
> popped.
>
>
>
> A is not the  penultimate node for traffic to to CPE2 (b) so the BIER
> header is not popped.
>
>
>
> Zzh> So the context is that B does support BIER. In that case, A won’t do
> PHP for B at all.
>
>
>
> Both a' and b is sent to B.
>
>
>
> B forward a' natively to CPE1.
>
>
>
> B is the penultimate node for traffic to to CPE2 (b) so the BIER header is
> popped.
>
>
>
> b' is forwarded to C and onto CPE2
>
>
>
> Works just fine.
>
>
>
> Question: If the PHP is a "per node decision" how is A stopped from doing
> PHP for b?
>
>
>
> Zzh> Please see above :-)
>
> Zzh> Thanks.
>
> Zzh> Jeffrey
>
>
>
> /Loa
>
>
>
>
>
>
>
> On 22/08/2020 05:20, Gyan Mishra wrote:
>
> >
>
> > I support advancing this critical draft forward.  I agree that the PHP
>
> > feature traditionally used with MPLS and has been adopted by SR and
>
> > now by BIER for similar reasons of being able to pop the BIER header
>
> > similar to what is done with SR PHP concept and now extensible with
>
> > BIER for Non-BRF capable PE's.
>
> >
>
> > BIER IPv6 is still being developed, however I think maybe BIERin6
>
> > could take advantage of  PHP by popping the encapsulated L2 1/2 BIER
>
> > shim for "Non-BFR" capable PE.  I think for BIERv6 as the BIER header
>
> > is encoded in DOH it may be difficult to support PHP.
>
> >
>
> > Thanks
>
> >
>
> > Gyan
>
> >
>
> > On Wed, Aug 19, 2020 at 2:01 PM Mankamana Mishra (mankamis)
>
> > <mankamis=[e-mail]
>
> > <mailto:[e-mail] <[e-mail]>>> wrote:
>
> >
>
> >     Support moving this document forward. ____
>
> >
>
> >     __ __
>
> >
>
> >     *From: *BIER <[e-mail] <mailto:[e-mail]>>
>
> >     on behalf of "IJsbrand Wijnands (iwijnand)"
>
> >     <iwijnand=[e-mail]
>
> >     <mailto:[e-mail] <[e-mail]>>>
>
> >     *Date: *Monday, August 17, 2020 at 11:56 AM
>
> >     *To: *Greg Shepherd <[e-mail] <mailto:[e-mail]>>
>
> >     *Cc: *"[e-mail] <mailto:[e-mail]>" <[e-mail]
>
> >     <mailto:[e-mail] <[e-mail]>>>
>
> >     *Subject: *Re: [Bier] WGLC: draft-ietf-bier-php____
>
> >
>
> >     __ __
>
> >
>
> >     In support moving this draft forward, ____
>
> >
>
> >     __ __
>
> >
>
> >     Thx,____
>
> >
>
> >     __ __
>
> >
>
> >     Ice.____
>
> >
>
> >     Sent from my iPhone____
>
> >
>
> >
>
> >
>
> >     ____
>
> >
>
> >         On 13 Aug 2020, at 05:31, Greg Shepherd <[e-mail]
>
> >         <mailto:[e-mail] <[e-mail]>>> wrote:____
>
> >
>
> >
>
> >         Please read and respond to this thread. We had a WGLC for this
>
> >         draft previously, but had no response. Let’s do better. ____
>
> >
>
> >         __ __
>
> >
>
> >
>
> > https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-iet
> <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-iet>
>
> > f-bier-php/______;!!NEt6yMaO-gk!Ws4otxDsuVKTsaEjyRKVYz-hcmmmGgDiE7Cnpq
>
> > vfA3s4r-JLyE8pK0PVq2FrBGNX$
>
> >
>
> >         __ __
>
> >
>
> >         Start of short LC timer. Respond by Aug 19..____
>
> >
>
> >         __ __
>
> >
>
> >         - Shep____
>
> >
>
> >         (Chairs)____
>
> >
> Juniper Business Use Only
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> > 0PVq9z6N_yR$
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> >
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> > --
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> >
>
> > *Gyan Mishra*
>
> >
>
> > /Network Solutions A//rchitect /
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> >
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> --
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>
>
> Loa Andersson                        email: [e-mail]
>
> Senior MPLS Expert                          [e-mail]
>
> Bronze Dragon Consulting             phone: [phone]
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