Hi Joel,
I would like to echo the arguments that Bruno has made (and quote part
of it) in his summary and then previously on this thread.
/QOUTE/
/The point was related to the usefulness of the optional feature,
which has been challenged./
/I was trying to say the required argumentation to declare usefulness
or usefulness is asymmetric, from a logical discussion stand point./
//
/a) It only requires one person to find it useful, in order to make
the feature useful (for that person)./
/b) In order to state that this is un-useful, requires to prove that
this is never useful./
/UNQOUTE/
It’s pure logic!
Please check inline below.
-----Original Message-----
From: spring <spring-boun...@ietf.org> On Behalf Of Joel M. Halpern
Sent: 03 March 2020 21:54
To: bruno.decra...@orange.com; Martin Vigoureux
<martin.vigour...@nokia.com>; spring@ietf.org
Subject: Re: [spring] WGLC -
draft-ietf-spring-srv6-network-programming
I'm sorry, but "in my gear I want an option to move some work around,
so I need a protocol behavior for that" is not usually, in and of
itself, enough reason to add an optional feature to a protocol.
*/[KT] To start with, there are other/more use-cases for PSP as have
been discussed on the list over the course of the WGLC and before then.
I think you are referring to the use-case that Dan Voyer brought up
with legacy hardware - I don't see an issue of being practical and
sensitive to real world problems and scenarios. This is what results
in actual adoption and deployment success. We have options everywhere
- the EH themselves are optional … IIRC HBH options were not so
recently made optional out of pure consideration of the actual metal
out there in the Internet! /**/😊/*
At one point there was an argument that PSP was needed for compliant
devices that would not be able to process the packet. It has been
pointed out since that such devices would not comply to 8200 (not
because of PSP, but because being able to ignore an exhausted routing
header is required in 8200). Having an optional feature to take care
of devices which violate a standard again requires some strong
evidence to justify it.
*/[KT] A device can be conformant with RFC8200 even if were punting
the packets for local s/w processing in the presence of an EH (or RH
in this case). In that case, it would not be doing line-rate
forwarding which is the requirement here. This is again a very
practical consideration that is rooted in real world problems and
deployments. /*
So no, from where I sit I have not seen a clear explanation of the
value for PSP.
*/[KT] There have been many use-cases and values expressed for PSP by
those that have implemented and deployed it. I can understand if you
do not appreciate them. But they are optional and it is unfair to deny
it to those who need it./*
I also do not understand why the authors have resisted the usual
solution to this sort of disagreement, namely moving the feature to a
separate document. Given the structure of the network programming
draft, and that it is not exhaustive in either flavors or programming
behaviors, there is no violence done to the draft by removing this flavor.
*/[KT] I think we can go by the track record through the progression
of this draft. The contentious topics related to SRH insertion were
removed by the authors based on WG feedback and technical arguments –
note this was done after it was a WG document. This WGLC has gone
beyond the usual timeframe and resulted in unusually large amount of
technical discussions. We do see that the document has undergone
through multiple changes to improve the text as well as fix certain
issues. /*
*//*
*/So by no stretch of imagination can we say that the authors have
been resistant to change when such a change was technically warranted.
I do not believe the removal of PSP makes practical and technical
sense for those who have implemented and deployed it with real world
scenarios in
mind./*
*//*
*/Thanks,/*
*/Ketan/*
Yours,
Joel
On 3/3/2020 10:49 AM, bruno.decra...@orange.com
<mailto:bruno.decra...@orange.com> wrote:
> Fernando
>
>> From: spring [mailto:spring-boun...@ietf.org] On Behalf Of
Fernando
>> Gont
>> Sent: Monday, March 2, 2020 9:23 PM
>> To: Martin Vigoureux; spring@ietf.org <mailto:spring@ietf.org>
>> Cc: 6...@ietf.org <mailto:6...@ietf.org>; 'i...@ietf.org';
>> draft-ietf-spring-srv6-network-programming
>> Subject: Re: [spring] WGLC -
>> draft-ietf-spring-srv6-network-programming
>>
>> Martin,
>>
>> As an Area Director, what are your thoughts regarding Bruno's
claim
>> that this working group (Spring) doesn't have the necessary skills
>> for evaluating the need of a functionality (PSP) that this wg is
>> including in draft-ietf-spring-srv6-network-programming?
>>
>> Specifically, Bruno has noted (in
>>
https://mailarchive.ietf.org/arch/msg/spring/or8086G4iYfee5_Icw4PnhkPLBo/):
>>
>> ---- cut here ----
>> Independently of RFC 8200, the question has been raised with
regards
>> to the benefit of PSP.
>> My take is that PSP is an optional data plane optimization.
Judging
>> its level of usefulness is very hardware and implementation
>> dependent. It may range anywhere from "not needed" to "required
for my platform"
>> (deployed if you are network operator, or been sold if you are a
>> vendor), with possible intermediate points along "n% packet
>> processing gain", or "required when combined with a specific other
>> feature". I don't think that the SPRING WG can really evaluate
this
>> point (lack of hardware knowledge, lack of detailed information on
the hardwares).
>> ---- cut here ----
>>
>>
>> Doesn't this sound a bit like a group is shipping something that
it
>> cannot really understand?
>
>
> There have been replied and statement from the WG. E.g. From Dan
(network operator) & Jingrong (vendor).
>
https://mailarchive.ietf.org/arch/msg/spring/ErcErN39RIlzkL5SKNVAeEWpn
> AI/
>
> My comment is that a statement such as "(1) reduce the load of
final destination.", while true in general, is difficult to evaluate,
e.g. in term of packet processing gain, or NPU processing resource gain.
> One can say "not on my hardware", but nobody can say "not in your
hardware".
>
> And I think that this is along Joel reply (although I would not
want
> to speak for Joel) "Do you have any comments on what appears to be
the
> significant increase in complexity on the device performing PSP?
The
> question I am trying to get at is about the tradeoff, which needs
one to evaluate both sides."
>
https://mailarchive.ietf.org/arch/msg/spring/CMSX7ijacRdG8qHlla61ylJNg
> go/
>
>
> So in the end, what we have is the statement "(1) reduce the load
of final destination.".
>
> Thanks,
> --Bruno
>
>> Thanks,
>> Fernando
>>
>>
>>
>>
>> On 2/3/20 15:53, Martin Vigoureux wrote:
>>> WG,
>>>
>>> as I had indicated in a previous message I am the one evaluating
>>> consensus for this WG LC.
>>>
>>> I have carefully read the discussions on the list. I acknowledge
>>> that disagreements were expressed regarding what a particular
piece
>>> of text of RFC 8200 says, and on which this document builds to
>>> propose an optional capability. Since RFC 8200 is not a product
of
>>> the SPRING WG, I have paid specific attention to the messages
([1],
>>> [2], and [3]) sent by the responsible AD of 6MAN and of RFC8200.
>>>
>>> My overall conclusion is that there is support and rough
consensus
>>> to move this document to the next stage.
>>>
>>> Bruno will handle the immediate next steps.
>>>
>>>
>>> Martin
>>>
>>>
>>> [1]
>>>
https://mailarchive.ietf.org/arch/msg/spring/67ZG76XRezPXilsP3x339rG
>>> pcso/
>>> [2]
>>>
https://mailarchive.ietf.org/arch/msg/spring/plidxjZFBnd4_mEzGsLC76F
>>> ZmQ0/
>>> [3]
>>>
https://mailarchive.ietf.org/arch/msg/spring/uBYpxPyyBY6bb86Y2iCh3jS
>>> IKBc/
>>>
>>> Le 2019-12-05 Ã 18:15, bruno.decra...@orange.com
<mailto:bruno.decra...@orange.com> a écrit :
>>>> Hello SPRING,
>>>>
>>>> This email starts a two weeks Working Group Last Call on
>>>> draft-ietf-spring-srv6-network-programming [1].
>>>>
>>>> Please read this document if you haven't read the most recent
>>>> version, and send your comments to the SPRING WG list, no later
than December 20.
>>>>
>>>> You may copy the 6MAN WG for IPv6 related comment, but consider
not
>>>> duplicating emails on the 6MAN mailing list for the comments
which
>>>> are only spring specifics.
>>>>
>>>> If you are raising a point which you expect will be specifically
>>>> debated on the mailing list, consider using a specific
email/thread
>>>> for this point.
>>>>
>>>> This may help avoiding that the thread become specific to this
>>>> point and that other points get forgotten (or that the thread
get
>>>> converted into parallel independent discussions)
>>>>
>>>> Thank you,
>>>>
>>>> Bruno
>>>>
>>>> [1]
>>>>
https://tools.ietf.org/html/draft-ietf-spring-srv6-network-programm
>>>> ing-05
>>>>
>>>>
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>>
>>
>> --
>> Fernando Gont
>> e-mail: ferna...@gont.com.ar <mailto:ferna...@gont.com.ar> ||
fg...@si6networks.com <mailto:fg...@si6networks.com> PGP
>> Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1
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>
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