Re: [IPv6] 6MAN: looking for feedback to draft-eckert-6man-qos-exthdr-discuss (Re: New Version Notification for ...)

[Toerless Eckert <[e-mail]>]

Wrt to flow label, and that also goes a bit into the question of whether or how to stuff the
flow label back into IPv4 via Tom's draft (should we also inherit without additional warnings or
failsafes stuff that didn't work in IPv4 back into IPv4):

For me, the final word on IPv6 flow label is still this here:

https://bapk-videos.mamadrum.net/pk/IETF-099-Prague-videos/03-joel-jaeggli-8.mp4

And yet we did afterwards still have attempts to introduce new flow label semantics through configuration
in the ietf. Can we please upgrade the level of this pechakucha's conclusion to proposed standard ?

The goal of the extension header i am proposing does include the feature to allow failure of
QoS experiments, even those we may have worked to standardize (as opposed to experimental, informational etc..).

And with the extension header, such failures would only eat up one value of the method code-point in the extension
header, not a whole header field like we effectively did when the first two flow-label semantics started to
collide.

Cheers
    Toerless

On Tue, Mar 05, 2024 at 10:31:09AM -0800, Tom Herbert wrote:
> On Tue, Mar 5, 2024 at 6:41 AM Tim Chown
> <Tim.Chown=[e-mail]> wrote:
> >
> > Hi,
> >
> > On 4 Mar 2024, at 23:02, Tom Herbert <tom=[e-mail]> wrote:
> >
> > On Mon, Mar 4, 2024 at 12:37 PM Toerless Eckert <[e-mail]> wrote:
> >
> >
> > Dear 6MAN-WG:
> >
> > I have just posted an extremely rough draft draft-eckert-6man-qos-exthdr-discuss, to help start a discussion
> > about common IPv6 extension headers for (mostly) stateless QoS beyond what we can do with just DSCP.
> >
> >
> > Hi Toerless,
> >
> > You might want to look at draft-herbert-fast and
> > draft-herbert-host2netsig. It looks like these have similar goals.
> >
> >
> > And that is similar in spirit to what the CERN experiments are doing with flow label semantics, which would/could be HbH header information if then insertion penalty were not so high.
> 
> Hi Tim,
> 
> The CERN experiment might be okay as an experiment, but overloading
> the twenty bit information of flow label is neither scalable nor
> standardizable. This is especially true for those proposals that want
> to set some bits differently within the same flow and expect that
> routers will ignore those bits for ECMP hash.
> 
> I am interested in what you mean by " if then insertion penalty were
> not so high".
> 
> Tom
> 
> 
> >
> > https://www.ietf.org/archive/id/draft-cc-v6ops-wlcg-flow-label-marking-02.html
> >
> > And there are others, each doing something slightly different, when we’d ideally have one EH to rule them all.
> >
> > Tim
> >
> >
> > Right now this is a discussion draft not intended to become RFC because it's my impression that the
> > 6MAN community might benefit from some useful summary of how DetNet (and potentially other WGs) might
> > use this work, but this would not be part of a final spec draft, and likewise i have a wide range of
> > open questions instead of answers, and i included those questions into the draft seeking for feedback from
> > 6MAN.
> >
> > Overall, i didn't want to go down a possible rabbit hole of working on details of the spec if it just
> > turns out to involve insurmountable IETF process obtacles to go this route. For example, we could continue to
> > standardize all advanced forwarding functions only into MPLS and ignore IPv6 as DetNet has done so far
> > (*mumble ;-).
> >
> > The lack of such extension headers has IMHO held back innovation into better (stateless) QoS, especially
> > in many controlled networks since at least 25 years, for example when draft-stoica-diffserv-dps
> > was abandomed because it was too painfull trying to get to through all the IETF IPv6 bureaucracy -
> > for just one algorithm, when there are so many that would deserve experimentation in specific
> > networks. But given the good recent/ongoing work for example into  I-D.ietf-6man-hbh-processing,
> > i would hope that we're closer now to actually wanting our extensibility of IPv6 actually be used
> > by the industry (instead of all this happening only in MPLS).
> >
> > With DetNet we are too in the situation that we have multiple candidates on the table and IMHO
> > it will not be very useufl trying to run a lottery for a single "winner" and standardize just that.
> >
> > I have seen a lot more success in the industry by just letting different algorithms compete with
> > each othrer in products and let the market decide. That was quite a lot happening in e.g.: packet
> > scheduling in routers at least since the end of the 90th when in my impression every new
> > hardware forwarding router implemented it's own new packet scheduler based on the just hired lead
> > engineers PhD thesis. And over a period of 20 years, a lot of commonality and industry
> > knowledge evolved in that space. For this type of scheduling, this innovation was possible because it did not
> > require new packet headers, but just a lot of (ab)use of DSCP and/or more or less horrenduous
> > QoS configurations. But for those solutions that do require additional in-packet-QoS metadata,
> > we never created a viable method where it was easy for the  innovators/implementers to concentrate
> > on the novelties of the algorithm in question and get all the knucklehead "how to packetize and what generic
> > requirements/functionalities" be provided as much as possible by an existing framework/RFC.
> >
> > So, i'd be very happy to find interest to help progress this work, aka: writing something
> > that ultimately would become a draft-ietf-6man-common-qos-exthr or the like. I have tentatively
> > asked for a slot for IETF119 6MAN to present and get feedback, if you think that would be time well
> > spent, pls. chime in.
> >
> > Cheers
> >    Toerless, for the authors
> >
> > On Mon, Mar 04, 2024 at 12:30:53PM -0800, [e-mail] wrote:
> >
> > A new version of Internet-Draft draft-eckert-6man-qos-exthdr-discuss-00.txt
> > has been successfully submitted by Toerless Eckert and posted to the
> > IETF repository.
> >
> > Name:     draft-eckert-6man-qos-exthdr-discuss
> > Revision: 00
> > Title:    Considerations for common QoS IPv6 extension header(s)
> > Date:     2024-03-04
> > Group:    Individual Submission
> > Pages:    27
> > URL:      https://www.ietf.org/archive/id/draft-eckert-6man-qos-exthdr-discuss-00.txt
> > Status:   https://datatracker.ietf.org/doc/draft-eckert-6man-qos-exthdr-discuss/
> > HTMLized: https://datatracker.ietf.org/doc/html/draft-eckert-6man-qos-exthdr-discuss
> >
> >
> > Abstract:
> >
> >   This document is written to start a discussion and collect opinions
> >   and ansers to questions raised in this document on the issue of
> >   defining IPv6 extension headers for DETNET-WG functionality with
> >   IPv6.
> >
> >
> >
> > The IETF Secretariat
> >
> >
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