Re: [sfc] I-D Action: draft-ietf-sfc-nsh-ecn-support-06.txt

Hi Joel,

On Mon, Sep 13, 2021 at 5:08 PM Joel M. Halpern <jmh@joelhalpern.com> wrote:
> While such a facility (to inform about packet changes) has
> understandable value, I tend to doubt the likelihood of it being used.
> It seems an unlikely upgrade for a SF builder to bother implementing,
> since it is likely to be significant effort.  And existing SFs (including
> all those behind proxies) will not support it.

The issue is covered in a Section in the draft so at least it isn't
just ignored. Would you recommend perhaps one more pass to polish the
draft and then proceed to a WG Last Call without adding such a
mechanism?

Thanks,
Donald
===============================
 Donald E. Eastlake 3rd   +1-508-333-2270 (cell)
 2386 Panoramic Circle, Apopka, FL 32703 USA
 d3e3e3@gmail.com

> Yours,
> Joel
>
> On 9/13/2021 4:56 PM, Donald Eastlake wrote:
> > This revision has minor wording improvements.
> >
> > To my mind there is one substantial issue with this draft: What to do
> > about SFs that add or remove packets from a flow or lengthen or
> > shorten such packets. If this is ignored, the document is much less
> > useful for such flows. The simplest solution seems to be that such SFs
> > should optionally signal forward in separate packets the changes they
> > have made, of this sort, to flows. I plan to look into adding such a
> > facility.
> >
> > Thanks,
> > Donald
> > ===============================
> >   Donald E. Eastlake 3rd   +1-508-333-2270 (cell)
> >   2386 Panoramic Circle, Apopka, FL 32703 USA
> >   d3e3e3@gmail.com
> >
> > On Mon, Sep 13, 2021 at 4:06 PM <internet-drafts@ietf.org> wrote:
> >>
> >>
> >> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> >> This draft is a work item of the Service Function Chaining WG of the IETF.
> >>
> >>          Title           : Explicit Congestion Notification (ECN) and Congestion Feedback Using the Network Service Header (NSH) and IPFIX
> >>          Authors         : Donald E. Eastlake
> >>                            Bob Briscoe
> >>                            Yizhou Li
> >>                            Andrew G. Malis
> >>                            Xinpeng Wei
> >>          Filename        : draft-ietf-sfc-nsh-ecn-support-06.txt
> >>          Pages           : 33
> >>          Date            : 2021-09-13
> >>
> >> Abstract:
> >>     Explicit congestion notification (ECN) allows a forwarding element to
> >>     notify downstream devices of the onset of congestion without having
> >>     to drop packets. Coupled with a means to feed information about
> >>     congestion back to upstream nodes, this can improve network
> >>     efficiency through better congestion control, frequently without
> >>     packet drops. This document specifies ECN and congestion feedback
> >>     support within a Service Function Chaining (SFC) architecture domain
> >>     through use of the Network Service Header (NSH, RFC 8300) and IP Flow
> >>     Information Export (IPFIX, RFC 7011).
> >>
> >>
> >>
> >> The IETF datatracker status page for this draft is:
> >> https://datatracker.ietf.org/doc/draft-ietf-sfc-nsh-ecn-support/
> >>
> >> There is also an htmlized version available at:
> >> https://datatracker.ietf.org/doc/html/draft-ietf-sfc-nsh-ecn-support-06
> >>
> >> A diff from the previous version is available at:
> >> https://www.ietf.org/rfcdiff?url2=draft-ietf-sfc-nsh-ecn-support-06
> >>
> >>
> >> Internet-Drafts are also available by anonymous FTP at:
> >> ftp://ftp.ietf.org/internet-drafts/
> >>
> >>
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