[R-C] LEDBAT - introductions?

[Michael Welzl]

On Apr 4, 2012, at 12:56 PM, eemeaesarzah wrote:

> On 2012-04-03 15:06, David Ros wrote:
>
>> David.
>>
>> PS: I have a longer summary, but I tried to keep this short as  
>> requested :-)
>>
> I am interested on your longer summary and perhaps you can educate  
> us about the application of LEDBAT CC algorithm to real-time media  
> specially on this note "by yielding when delay increases and by  
> being less aggressive that TCP in grabbing extra bandwidth".

to answer that bit, let me quote from my own previous email describing  
LEDBAT:

"it's one out of many mechanism that use delay (as a result of  
increasing queue length) as an earlier indication of congestion.  
without adding a mechanism like that "use the TCP equation as a lower  
limit" or something like that, reacting earlier than standard TCP  
makes you less aggressive - and this is what LEDBAT was designed to  
be: a mechanism that "gives way" to TCP, making itself suitable for  
background scavenger-like traffic."

I don't think anybody advocated using LEDBAT as it is here. But  
personally, I would favor "adjusting" LEDBAT by e.g. adding the "TCP  
equation as a lower limit" trick (which I think is neat!) and tuning  
its parameters over having a from-scratch design of a new delay-based  
mechanism. LEDBAT has already undergone some investigation, and so  
we'd have a more stable basis.

Cheers,
Michael