Minutes IETF109: nwcrg

Meeting Minutes Coding for efficient NetWork Communications Research Group (nwcrg) RG
Title Minutes IETF109: nwcrg
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Last updated 2020-12-10

Meeting Minutes

# IETF 109 NWCRG Meeting Minutes

* [Datatracker](https://datatracker.ietf.org/rg/nwcrg/)
* [Github](https://github.com/irtf-nwcrg/rg-materials/)
* [Meeting record](https://www.youtube.com/watch?v=rBGh7clvhUc)

## nwcrg online meeting

Online meeting on Tuesday November 17, 2020, 7:30-8:30 (UTC) Session II
[Time Zone


Participation will take place through Meetecho (please connect in advance):
    - [Meetecho participant
    guide](https://www.ietf.org/how/meetings/109/session-participant-guide/) -
    [links to Meetecho


#### 00- Welcome, administrative and general matters
(Chairs) (10')

### Updates of existing works:
#### 01- "BATS Coding Scheme for Multi-hop Data Transport" I-D
(Raymond Yeung) (10+5')


#### 02- "Coding and congestion control in transport" I-D
(Nicolas Kuhn) (10+5')
Update of the document and new experimental results.

- MJM: it's important work as congestion control versus FEC always comes as a
question. Do you know anybody doing research on it? - NK: we know LOOPS
activity, we're in the process of adding a state of the art section in the
document. We couln't do that for this meeting. - VR: it can be quite ambitious.
- Morten V. Pedersen: it's important work. Could you clarify the situation
where coding happens above the transport (e.g., above TCP that already corrects
losses). - NK: we mean coding at application level. Right now we discuss all
the possible cases. Sure it does not make sense if TCP is used underneath, and
this is what we tried to explain. - Carsten Bormann: have you read this paper
suggesting to replace the notion of fairness with the notion of "not doing
harm". It is presented during the IRTF Open meeting ["Beyond Jain’s Fairness
Index: Setting The Bar For the Deployment of Congestion Control
- CB: I think the "FEC below transport" category should be called "FEC
disconnected from transport". I think that most people realize that FEC has to
send signals to the transport. So it's more a question of signaling between FEC
and transport. If FEC and transport are integrated, this is implicit. But if
you have different entities, as was the case with a Tetrys tunnel, then the
interesting question is: how do you do this?  How do you actually send the
signal? The only way that was found is through ECN marks. But to what extent
can you actually minimize harm by doing so? Do you really have to completely
emulate the situation where all losses indicate congestion or can you find some
more intelligent ways? The FEC layer has more information about it than the
congestion layer, and it would be nice to relay some of it to the congestion
control, but they can only communicate using the language they understand. This
is an area where interesting research questions are that I'd like to see in the
document. - NK: For 1st part, I read paper and we should include it in the
draft, but we are afraid to open the pandora box on fairness. We currently have
lots of QoS mechanisms between users. It's something that needs to be
discussed, and it's very policy oriented. The definition "not to harm others"
is something we tried to map in this work. I would disagree however when you
suggest to rename FEC below as FEC disconnected, because we mention all these
situations where you can have signaling. And it's protocol specific. I would
agree concerning the research question. Guarrantying QoE while keeping fairness
to other flows is something we are currently covering, the definition of
signals for the "FEC below transport" case may be not.

### Additional presentations

#### 03- "Repair patterns for sliding window codes"
(Morten V. Pedersen) (10')

### Wrap-up, next steps
(Chairs, all) (5')

Chairs: We're short of time, let's continue on the mailing list.