Re: [spring] Network Programming - Penultimate Segment Popping

["Darren Dukes (ddukes)" <[e-mail]>]

Hi Ron. I am trying to be precise in my posts.  Please do not interpret them as dismissive.
I have observed, in your original post, the conflation of SRH insertion within an SR Domain with the PSP behavior defined in network programming.
Whether this was intentional or not, I do not know.
Regardless, it is wrong.

I have used very specific words to describe the PSP operation within an SR Domain since they are easy to find in RFC8200’s discussion on the topic.

“The SRH is only removed by the node identified in the destination address field of the IPv6 header.”

The PSP behavior does belong in network programming.

Thanks
  Darren

________________________________
From: Ron Bonica <[e-mail]<mailto:[e-mail]>>
Sent: Thursday, December 5, 2019 3:39 PM
To: Darren Dukes (ddukes)
Cc: SPRING WG; 6man
Subject: RE: Network Programming - Penultimate Segment Popping

Darren,

I understand that the PSP operation:

  *   Is executed on the penultimate segment endpoint only
  *   Is signaled by the source node using bits in the IPv6 destination address
However, those facts are orthogonal to the question that I asked. So, I will try to ask my question again. Please read it carefully and answer the question that is asked. (Dismissive responses will only make me grumpier.)

Currently, there is no consensus that IPv6 allows insertion of extension headers by intermediate nodes, even if those intermediate nodes are segment endpoints . Given this lack of consensus, the authors of network programming have wisely agreed to remove header insertion from the draft.

Likewise, there is no consensus that IPv6 allows removal of extension headers by intermediate nodes, even if those intermediate nodes are segment endpoints. Why, then, have the authors of network programming not agreed to remove PSP from the draft?

                                                                                           Ron




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From: Darren Dukes (ddukes) <[e-mail]<mailto:[e-mail]>>
Sent: Thursday, December 5, 2019 11:50 AM
To: Ron Bonica <[e-mail]<mailto:[e-mail]>>
Cc: SPRING WG <[e-mail]<mailto:[e-mail]>>; 6man <[e-mail]<mailto:[e-mail]>>
Subject: Re: Network Programming - Penultimate Segment Popping

Hello Ron, I believe this is the fifth time you have raised this comment in 6man and/or spring.
The comment has been addressed in earlier iterations.

Let me recap.

With the PSP behavior, the SRH is only removed by the node identified in the destination address field of the IPv6 header.

That destination address was placed in the SRH by the SR Source node, fully expecting the behavior.

Thanks
  Darren

Iterations:
[2019-09-06] https://mailarchive.ietf.org/arch/msg/spring/7zMgIwEY9AipZCCGO9KnT2CGH3o<https://urldefense.com/v3/__https:/mailarchive.ietf.org/arch/msg/spring/7zMgIwEY9AipZCCGO9KnT2CGH3o__;!8WoA6RjC81c!T981Kv39IIsXJ2I3jiE36cVdwwLgIWJoFBUg_AnU8IEb9Y_6GbNWAykRc82ck-xk$>
[2019-09-27] https://mailarchive.ietf.org/arch/msg/spring/4_Slu3kkHwduZZPFJJmRUkmoTVo
[2019-10-14] https://mailarchive.ietf.org/arch/msg/spring/u536YH4tv7kKRq_b9_x9gBYpO9c
[2019-10-21] https://mailarchive.ietf.org/arch/msg/spring/4pikRli_HSECun9AbwfpmOF5KLI
[2019-12-04] https://mailarchive.ietf.org/arch/msg/spring/oDWLbRDqKCaF5Xa-QvKY6mk_D5E


On Dec 4, 2019, at 11:37 AM, Ron Bonica <rbonica=[e-mail]<mailto:rbonica=[e-mail]>> wrote:

Pablo,

It seems to me that the following are equally controversial:


  *   A transit node inserting a Routing header
  *   A transit node removing a Routing header


We have agreed to move discussion of RH insertion out of the Network Programming draft and into another draft. Shouldn’t discussion of RH removal be treated similarly.

This comment applies to Penultimate Segment Popping (PHP) in the Network Programming draft.

                                                                 Ron


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