Re: [PANRG] Path Selection for Multiple Paths

[Spencer Dawkins at IETF <[e-mail]>]

Hi, Markus,

On Mon, Aug 2, 2021 at 10:40 AM <[e-mail]> wrote:

> Dear Spencer, all,
>
> I just had a look into the IETF111 PANRG recordings and found the
> presentation about Path Selection for Multiple Paths very refreshing. It
> would be good to have a place where multipath challenges and solutions can
> be consolidated in IETF. The challenges you brought up in your presentation
> are related to multipath transport layer approaches like
> MP-TCP/QUIC/SCTP/DCCP, but also (partly) to any other approach on layers
> different to this, e.g. GRE bonding (RFC8157) etc. pp. That's why I
> appreciated your updated presentation title "Path Selection for Multiple
> Paths" instead of "Path Selection for Multiple Paths in QUIC".
>

Thanks for your kind words!


> The individual topics you raised (and I expanded)
>
>   - scheduling
>   - reordering
>   - path estimation by CC or other means
>   - sequencing
>   - loss detection and handling
>   - nested or concatenated CC - e.g. QUIC over MP-DCCP (3GPP ATSSS)
>
> and also their possible interworking is an interesting research area.
>
> In the MP-DCCP development we are quite advanced in the identification of
> this challenges and for some of them we are providing quite efficient
> solutions. Some of them are documented as part of the MP-DCCP protocol
> draft in TSVWG others like scheduling, reordering and fast packet loss
> detection are provided to ICCRG or published in academic paper.
>

I think this is a key question for PANRG (and, more broadly, potentially
for other IRTF research groups). I like your topic list. Do you have
thoughts about which topics involve loss detection and congestion control,
which likely are (should be?) in scope for ICCRG, and which ones are
broader questions?

I made the assertion last week in PANRG that path selection was in scope,
and we seemed to agree on that. I'm also wondering about path estimation
(especially by "other means"), and about nested or concatenated paths
(assuming that not all the issues with nested or concatenated paths are
about CC).

But I'd like to know what you think, and what others think as well.


> I encourage and invite people interested in that research area to look
> into https://multipath-dccp.org as a nice little playground. The provided
> MP-DCCP Linux reference implementation there provides at least initial
> support for all of the topics mentioned above.
>

Very nice! and thank you for posting the pointer here - I also keep an eye
on TSVWG, and I supported the "sense of the room" hum for adoption there.


> So full support from my side, please go ahead with this work!
>
> Is your plan now to shift your work on
> draft-dawkins-quic-multipath-selection to PANRG? And maybe change the title
> of your current draft to a more general title like for example "Path
> Selection in Multipath transport"?
>

Striking out "in QUIC'' in my presentation title on
https://datatracker.ietf.org/doc/draft-dawkins-quic-multipath-selection/
for PANRG was a guess, but it seems to have been a good guess. That's
certainly what I took away from last week's discussion, so, yes. I think
I'm changing the filename to -panrg- in the next submission.


> Btw. it's my first post to the PANRG mailing list 😊
>

Welcome to the party 😂

Best,

Spencer


> Br
>
> Marku
>