[e2e] Congestion control as a hot topic in IETF

Detlef Bosau detlef.bosau at web.de
Wed Mar 20 05:02:03 PDT 2013

Am 20.03.2013 00:06, schrieb Ted Faber:
> On Tue, Mar 19, 2013 at 10:37:54PM +0100, Detlef Bosau wrote:
>> However, what you wrote is no contradiction to what I said?
> You're talking about some mechanisms used to solve the problem those
> other folks described.  That isn't a contradiction, but I think you're
> missing the forest for the trees.


And so, it is not reasonable to review the purpose of congestion control?

Sometimes, I don't have the impression that I miss the forest for the 
trees, but we argue for different forests here.

Forest 1: Stability. (Nearly forgotten, hardly mentioned in many PhD 
theses I read throughout the last decade, the only .)

BTW: This forest is quite interesting, because from the system theory 
perspective, the often so called "buffer bloat problem" may well be a 
stability problem.
(BTW2: This forest is mentioned in the congavoid paper in a footnote - I 
strongly suspect this one of the most ignored footnotes in computer 

Forest 2: A reasonable trade off between work conservation on the one 
hand and acceptable delay on the other. IIRC this is Raj Jain's forest.

Forest 3: Sharing and allocation of resources. IIRC the most 
comprehensive, if to my understanding not that widely accepted, work in 
this direction is Keshav's PhD thesis. (Sorry for me sending this twice, 
I'm to stupid to correctly send an e-mail....) Unfortunately, I only 
read some of Keshav's papers and I'm still to read the whole thesis.

Forest 4: Finding the right trade-offs. From Dave Reed I know that he is 
strongly focussed on the overall delay. Some guys criticize the pure 
focus on throughput and mostly work conservation. (I'm sometimes told I 
must not talk about German politics here, but the "idle is evil" 
paradigm is the very core of quite some politics, be it the working 
morale of evangelic chistian churches or the work of the well known 
sociologist Max Weber.)
The quotient (throughput / delay) is at least a possible trade off here. 
Perhaps, it is neither the only one nor the best one. But when some guys 
argue with "knee" and "cliff" here, they refer to the well known picture 
by Jain/Kleinrock.

IIRC it was Joe Touch wo said (some time ago) the Internet may not give 
as always the resources we want, but we always get the resources we need.

Actually, I see two extremes: Dedicated resources e.g. as in the IntServ 
architecture (which is, to a certain degree, nothing else as a 
reinvented circuit switching system) on the one hand, "chaotic swarm 
intelligence" and collective praying on the other.

Now, the very purpose of our discussion, please correct me if I'm wrong, 
is to find a reasonable way in the middle - and that's what we are used 
to call "Best Effort".

Detlef Bosau
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