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

"Xiejingrong (Jingrong)" <> Mon, 24 August 2020 07:30 UTC

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From: "Xiejingrong (Jingrong)" <>
To: Gyan Mishra <>, "Mankamana Mishra (mankamis)" <>
CC: "IJsbrand Wijnands (iwijnand)" <>, Greg Shepherd <>, "" <>
Thread-Topic: [Bier] WGLC: draft-ietf-bier-php
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Date: Mon, 24 Aug 2020 07:30:42 +0000
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Subject: Re: [Bier] WGLC: draft-ietf-bier-php
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Hi Gyan,

Thanks for raising the PHP consideration in v6.

There is a thorough discussion in IETF community, especially 6man,  about Penultimate Segment Pop (PSP) ---- to Pop an EH when an IPv6 packet with EH reaches the node identified in the destination address [RFC8200 section 4].
This thorough discussion has led to a wide consensus among IETF community, and led to the progress of draft-ietf-spring-srv6-network-programming-17 to IETF last call.

So for BIERv6, I think the PSP can be very well supported to provide incremental deployment for Non-BIER-capable PEs.

Note, the whole DoH (not only the BIER option data) is popped/deleted when the BIERv6 packet is sent to the ultimate PE. Here is a diagram:


A is BFIR, D is Non-BFR router but acting as a BFER requesting PSP (signaling defined in draft-ietf-bier-php), and both B and C are BFRs (could be BFERs at the same time).

Packet from A to B: (IPv6 SA=A, DA=B) (DoH carrying BIER) (c-multicast packet).
Packet from B to C: (IPv6 SA=A, DA=C) (DoH carrying BIER) (c-multicast packet).
Packet from C to D: (IPv6 SA=A, DA=D) (c-multicast packet).


From: BIER [] On Behalf Of Gyan Mishra
Sent: Saturday, August 22, 2020 5:21 AM
To: Mankamana Mishra (mankamis) <>
Cc: IJsbrand Wijnands (iwijnand) <>; Greg Shepherd <>;
Subject: Re: [Bier] WGLC: draft-ietf-bier-php

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.



On Wed, Aug 19, 2020 at 2:01 PM Mankamana Mishra (mankamis) <<>> wrote:
Support moving this document forward.

From: BIER <<>> on behalf of "IJsbrand Wijnands (iwijnand)" <<>>
Date: Monday, August 17, 2020 at 11:56 AM
To: Greg Shepherd <<>>
Cc: "<>" <<>>
Subject: Re: [Bier] WGLC: draft-ietf-bier-php

In support moving this draft forward,


Sent from my iPhone

On 13 Aug 2020, at 05:31, Greg Shepherd <<>> wrote:

Please read and respond to this thread. We had a WGLC for this draft previously, but had no response. Let’s do better.

Start of short LC timer. Respond by Aug 19..

- Shep
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Gyan Mishra

Network Solutions Architect

M 301 502-1347
13101 Columbia Pike
Silver Spring, MD