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

["Jeffrey (Zhaohui) Zhang" <[e-mail]>]

Hi Loa,

Please see https://mailarchive.ietf.org/arch/msg/bier/xi6hpAdFLUBjYBVo9I4nr_418x4/ and https://mailarchive.ietf.org/arch/msg/bier/nbPn1uq8XM_RsQq0vaUBQZ5JYjM/.

The -06 revision is here: https://tools.ietf.org/html/draft-ietf-bier-php-06.

Thanks!
Jeffrey


Juniper Business Use Only

-----Original Message-----
From: BIER <[e-mail]> On Behalf Of Loa Andersson
Sent: Thursday, September 17, 2020 3:20 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, authors,

I don't think I saw a response on this.

/Loa


On 22/08/2020 13:57, Loa Andersson wrote:
> 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.
>
> 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 popped.
>
> 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?
>
> /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]>> 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]>>
>>     *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]>>
>>     *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]>> 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-ie
>> tf-bier-php/______;!!NEt6yMaO-gk!Xc7KbkW_lel3I36HaEzsUA2xMeb5gSroB5W1
>> mBAhG2yLZjknTH9OQEibSJ4RCvEs$
>>
>>         __ __
>>
>>         Start of short LC timer. Respond by Aug 19..____
>>
>>         __ __
>>
>>         - Shep____
>>
>>         (Chairs)____
>>
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>> --
>>
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>>
>> *Gyan Mishra*
>>
>> /Network Solutions A//rchitect /
>>
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>

--

Loa Andersson                        email: [e-mail]
Senior MPLS Expert                          [e-mail]
Bronze Dragon Consulting             phone: [phone]

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