Re: [iccrg] LEDBAT++, rLEDBAT, and slowdowns

[marcelo bagnulo braun <[e-mail]>]

below...

El 06/09/19 a las 17:02, Neal Cardwell escribió:
>
> Yes, rather than synchronizing using losses, I had something in mind along
> the lines I proposed earlier in this thread; something like
> BBR's PROBE_RTT mechanism:
>
>     ... the
>     only approach I can think of to achieve this would be for the flows to
>     coordinate in some fashion to all do a slowdown during overlapping
>     time intervals (as in BBR's PROBE_RTT mechanism).
>
> The details of BBR's PROBE_RTT mechanism are described in:
>    https://tools.ietf.org/html/draft-cardwell-iccrg-bbr-congestion-control-00#section-4.3.5


Thanks for the pointer. So, if i understand this correctly, essentially 
the proposed mechanism is that the flow slows down 10 seconds after the 
last update in the estimation of the base delay.

Is this it or am i missing something?

I understand that the expectation is that if there are several flows, 
the slow down of one them will cause the update of the base delay of 
several flows. These flows are now synchronized, so when they all slow 
down at the same time, they will cause even more flows to update their 
base delay estimation, and eventually all of them will be synchronized 
in their slow downs and then properly assess the base delay.

If this is so, I guess one question is how to know for sure that when 
they are in the uncoordinated state, the slow down of one of them will 
cause the update of the base delay of other flows, no?

Thanks, marcelo




> best,
> neal
> .
>