Hi Joel,
I would not like to misquote Bruno, but his conclusion on this topic
was very logical, practical and nuanced (again most likely comes from
working with a network operator).
/QOUTE/
/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). The fact that this has been implemented by some
platforms and deployed by some operators, is, to me, an indication
that it is useful for those cases. (I believe that an English proverb
is *"the proof of the pudding is in the eating"*. Although I'm
certainly missing part of its meaning and culture, in it's literal
reading, it seems to apply)./
/UNQOUTE/
I don’t believe we need to get into the details of the 18 [1]
publicly disclosed (I understand there are more) hardware
implementations from multiple vendors to debate the gains from PSP. I
don’t believe that is appropriate for an IETF mailing list or
pursuant to IETF policy or practice (as you say)?
Again, I like to make the point of how/why HBH processing was made
optional based on real world considerations when moving from RFC2460
to RFC8200. So options are good and necessary!
That said, let us turn the tables around. There is no technical
reason for not allowing PSP with SRH – all the ones that have been
brought up have been answered and clarified in the text as well as on the
mailer.
So I fail to understand the resistance of “the other side (including
yourself)”.
Therefore, I would suggest we go ahead with the declared Spring WG
consensus.
Thanks,
Ketan
[1]
https://tools.ietf.org/html/draft-matsushima-spring-srv6-deployment-s
t
atus-05#section-4.2
-----Original Message-----
From: Joel Halpern Direct <jmh.dir...@joelhalpern.com>
Sent: 04 March 2020 13:26
To: Ketan Talaulikar (ketant) <ket...@cisco.com>;
bruno.decra...@orange.com; Martin Vigoureux
<martin.vigour...@nokia.com>; spring@ietf.org
Subject: Re: [spring] WGLC -
draft-ietf-spring-srv6-network-programming
Bruno's statement, which you chose to quote, was that all it takes is
for one person to find something useful. I was responding to what
the chair said. It is not true as stated.
Having said that, I agree that more than one person has asked for this.
But the actual requirement is that there be a coherent and
understandable explanation of why the feature adds value. From where
I sit, I have not seen such an explanation. It is generally the
unbiased chair's job to judge whether sufficient explanation has been
given. But what Bruno said was not "explanation ... seems sufficient"
but rather the text you quoted. Which is not an accurate statement
of IETF policy or practice.
If there is a claim that there is significant problems on the
ultimate node for processing the SRH, I would like to see an
explanation of how an 8200 compliant node would have such problems.
In particular, unlike the MPLS case, the presence or absence of an
SRH with SL=0 has no effect on the number of forwarding lookups that
need to be performed. And 8200 requires the ability to ignore a routing header
with SL=0.
Yours,
Joel
On 3/4/2020 2:49 AM, Ketan Talaulikar (ketant) wrote:
> Hi Joel,
>
> Surely you are exaggerating when you say "one person" asked for
> something in the context of PSP? 😊
>
> Would you like to clarify?
>
> And also respond on the real life and practical deployment
scenarios and considerations that I've pointed out below? I doubt you
meant to just dismissing them without sharing your views?
>
> Thanks,
> Ketan
>
> -----Original Message-----
> From: Joel M. Halpern <j...@joelhalpern.com
<mailto:j...@joelhalpern.com>>
> Sent: 04 March 2020 13:16
> To: Ketan Talaulikar (ketant) <ket...@cisco.com
<mailto:ket...@cisco.com>>;
> bruno.decra...@orange.com <mailto:bruno.decra...@orange.com>;
Martin Vigoureux
> <martin.vigour...@nokia.com <mailto:martin.vigour...@nokia.com>>;
spring@ietf.org <mailto:spring@ietf.org>
> Subject: Re: [spring] WGLC -
> draft-ietf-spring-srv6-network-programming
>
> If we really want to say that it takes only one person asking for
something to put it in a planned RFC, then I guess we have to publish
all of the competing versions of route headers for v6, since we
clealry have more than 1 party asking for each variant?
> Put differently, no, putting something in because one person
asked for it (even with the caeat that it appears not to break) is
not how the IETF generally works. I do not know where Bruno got that
premise, but it does not match the history or written policies of the IETF.
>
> Yours,
> Joel
>
> On 3/4/2020 2:43 AM, Ketan Talaulikar (ketant) wrote:
>> 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
<mailto:spring-boun...@ietf.org>> On Behalf Of Joel M. Halpern
>> Sent: 03 March 2020 21:54
>> To: bruno.decra...@orange.com
<mailto:bruno.decra...@orange.com>;
Martin Vigoureux
>> <martin.vigour...@nokia.com
<mailto:martin.vigour...@nokia.com>>;
spring@ietf.org <mailto: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>
>> <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> <mailto:spring@ietf.org>
>>
>> >> Cc: 6...@ietf.org <mailto: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/ErcErN39RIlzkL5SKNVAeEWp
>> n
>>
>> > 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/CMSX7ijacRdG8qHlla61ylJN
>> g
>>
>> > 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 à 18:15, bruno.decra...@orange.com
<mailto: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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>>
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>>
>> >>>> ce message par erreur, veuillez le signaler a
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>>
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>>
>> >>>> etant susceptibles d'alteration, Orange decline toute
>>
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>>
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>>
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>>
>> >>>> This message and its attachments may contain confidential
or
>>
>> >>>> privileged information that may be protected by law; they
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the
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>>
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>>
>> >>>>
>>
>> >>>>
>>
>> >>>>
>>
>> >>>> _______________________________________________
>>
>> >>>> spring mailing list
>>
>> >>>> spring@ietf.org <mailto:spring@ietf.org>
<mailto:spring@ietf.org>
>>
>> >>>> https://www.ietf.org/mailman/listinfo/spring
>>
>> >>>>
>>
>> >>>
>>
>> >>> _______________________________________________
>>
>> >>> spring mailing list
>>
>> >>> spring@ietf.org <mailto:spring@ietf.org>
<mailto:spring@ietf.org>
>>
>> >>> https://www.ietf.org/mailman/listinfo/spring
>>
>> >>> .
>>
>> >>>
>>
>> >>
>>
>> >>
>>
>> >> --
>>
>> >> Fernando Gont
>>
>> >> e-mail: ferna...@gont.com.ar <mailto:ferna...@gont.com.ar>
<mailto:ferna...@gont.com.ar> ||
>> fg...@si6networks.com <mailto:fg...@si6networks.com>
<mailto:fg...@si6networks.com> PGP
>>
>> >> Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076
FFF1
>>
>> >>
>>
>> >>
>>
>> >>
>>
>> >> _______________________________________________
>>
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>>
>> >> spring@ietf.org <mailto:spring@ietf.org>
<mailto:spring@ietf.org>
>>
>> >> https://www.ietf.org/mailman/listinfo/spring
>>
>> >
>>
>> >
>>
_____________________________________________________________________
>> _
>>
>> > ___________________________________________________
>>
>> >
>>
>> > Ce message et ses pieces jointes peuvent contenir des
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>>
>> > confidentielles ou privilegiees et ne doivent donc pas etre
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>>
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>>
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si ce
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