Re: [nwcrg] [LOOPS] BOF co-chairs thinking on LOOPS next steps

Since most of your questions are related to FEC I copy the nwcrg. See <mjm>
below

mjm

Marie-José Montpetit, Ph.D.
Research Affiliate, MIT Media Laboratory
mariejose@mjmontpetit.com
mariejo@mit.edu

On July 30, 2019 at 10:23:04 AM, Spencer Dawkins at IETF (
spencerdawkins.ietf@gmail.com) wrote:

Hi, Mirja,

On Tue, Jul 30, 2019 at 5:34 AM Mirja Kuehlewind <ietf@kuehlewind.net>
wrote:

> Hi Carsten, hi Spencer,
>
> > On 25. Jul 2019, at 20:59, Spencer Dawkins at IETF <
> spencerdawkins.ietf@gmail.com> wrote:
> >
> > My impression, and Magnus might say I'm insane, was that Magnus is right
> on the edge of whether this work can be chartered without a second, working
> group-forming BOF. If the LOOPS community can't live without host-to-node,
> the community should add it. If the community can make use of LOOPS without
> host-to-node and add it later, the community might consider whether that
> reduces the scope of the initial proposed charter enough to help Magnus
> approve it :-)
>
> Yes, it would be possible to charter without another BoF a small and
> well-scoped group, however, it also would be possible to work on small and
> well-defined pieces of work without a new working group. This was one of
> the reasons why this was not a non-wg-forming BoF because it is not clear
> yet if a new group is needed or the resulting pieces of standardization
> work are small enough to fit into an existing group.
>
> Therefore, I really recommend focus on defining the standardising work
> items that you think are needed rather than trying to do any word-smithing
> of a potential charter (that eventually is not needed).
>

Thanks for giving me the chance to clarify - I really was talking about
chartering work, not just chartering a working group, but that wasn't clear
from my note. As you said, knowing what the work is, in more detail, will
help you and Magnus know what to do next.

So, my suggestion for the interested community is to nail down

   1. In order to "do LOOPS", what already exists, that can be used without
   changes?
   2. what already exists, but needs to be extended for LOOPS?
   3. what needs to be created, because nothing exists that meets the needs?

 I'm not a LOOPS proponent (the ADs asked me to chair the BOF about a month
before IETF 105), but speaking as someone who hasn't been involved in
depth, I wonder about

   1. How a sender tunes FEC dynamically - is that automatic, based on FEC
   mechanisms people are thinking about, or is there work to do there?

<mjm> There are FEC mechanisms to adapt coding dynamically based on
acknowledgments for example. In the QUICK implementation we will have flag
a RECOVERED packet that could be used to adapt the coding rate. Other
implementations or code-specific protocols are also available.

   1.
   How a sender knows whether to do FEC, retransmission, or both FEC and
   retransmission, dynamically?

<mjm> Well the use of FEC (or not) is a design decision.  Of course you
need the code (and the libraries). And then the decision will be based on
known link condition, goodput, expected performance, type of traffic
(video, time sensitive etc.). And finding a tunnel and PEPs if you need to.
And it can depend on path statistics and not being end to end. I am not
sure you could standardize that decision.

   1.
   How a sender knows that it shouldn't be doing anything, because anything
   it does won't help ("first, do no harm")?

<mjm> Of course in a congested network doing nothing is probably best.
Again there is a lot of work on the interaction of coding and congestion
control.

<mjm> Not everyone knows the things but there has been a lot of work in
FECFRAME (in IETF) and NWCRG. Someone did mention that a lot of the work
was done in a research group not a working group. But real implementations
exist in famous “networks".

<mjm> Since most of your questions are about erasure coding (coding for
packet loss) is that a direction LOOPS wants to take? Somekind of nwcWG?

mjm

Does everyone know how to do those three things, except me? :-)

Pointers to specifications would be awesome ...

Spencer

> Mirja
>
>
>
> --
LOOPS mailing list
LOOPS@ietf.org
https://www.ietf.org/mailman/listinfo/loops