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

[Stefan Holmer <[e-mail]>]

Sorry, accidentally sent too quickly...



On Mon, Nov 9, 2015 at 8:57 AM Stefan Holmer <[e-mail]> wrote:

> 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:
>

Simulations at slides 33-35
Emulations at slides 42-43
https://www.ietf.org/proceedings/interim/2015/07/19/rmcat/slides/slides-interim-2015-rmcat-1-2.pdf



>
>
>>
>> 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
>>
>>