Re: [rmcat] How we should handle feedback, and where the congestion should run

[Stefan Holmer <[e-mail]>]

On Sat, Nov 7, 2015 at 6:43 AM Randell Jesup <[e-mail]> wrote:

> On 11/6/2015 11:33 PM, Xiaoqing Zhu (xiaoqzhu) wrote:
> > In the eval-test-case draft, there is currently one test case dedicated
> > for exploring impact of two-way traffic (Sec. 5.3.  Congested Feedback
> > Link with Bi-directional RMCAT flows). Some corresponding graphs can be
> > found below (they may not reflect the most up-to-date algorithm
> > performance).
> >
> > * NADA:http://www.ietf.org/proceedings/92/slides/slides-92-rmcat-4.pdf
> > (page #9 and #10)
> > * SCReAM:
> >
> http://www.ietf.org/proceedings/interim/2014/11/09/rmcat/slides/slides-inte
> > rim-2014-rmcat-1-1.pdf (page #9)
> > (Sorry, I was not able to find one with GCC yet.).
>

GCC at:


>
> Thanks!  Those don't look too bad, though it can be hard to drill down
> into the details due to the PDF and thickness of the lines (and
> dense-ness of the graph); I found the closeups at the end of your pdf
> especially interesting (though not focused on this case).  One question
> that will be interesting as we develop a feedback mechanism is going to
> be the requirements from the algorithms on it, and the bandwidth it uses.
>
> I note NADA seems to be slower to respond to delay, though it also seems
> to do much better against competing TCP flows (and likely the two items
> are linked, which will make for some interesting tradeoffs and tuning to
> do).
>
> > Would like to know whether you think that current design of the test case
> > has captured gist of the issue encountered by two-way calls, or any
> > suggestions on additional test scenarios in that regard?
>
> I think showing a graph similar to Scream's, with congested and
> non-congested feedback paths is a useful comparison - much easier to see
> the impact.  Feedback bandwidth would be useful, though that might be
> fairly fixed right now (multiple of packet rate), so unless it's
> surprising it may not need graphing (just noting on the graph).
>
> --
> Randell Jesup -- rjesup a t mozilla d o t com
> Please please please don't email [e-mail]!  Way too much
> spam
>
>