[e2e] Why do we need congestion control?

Emmanuel Lochin emmanuel.lochin at isae.fr
Thu Apr 4 05:22:27 PDT 2013

On 04/04/2013 13:31, Detlef Bosau wrote:
> Simple question. Where is "fair dropping" that different from "fair 
> queueing"?

The FairDrop queue we have implemented to drive our tests with DCTP 
simply drops packet of the most opportunistic flows in the queue. 
Meaning that if you have 3 flows and a full queue of 30 packets, you 
should have 10 packets of each flow enqueued.


> I'm with you that we try to obviate the need of some reasonable 
> resource management in the Internet. However: When you require some 
> "fair dropping" mechanism, you could simply use the same 
> implementation and instead of scheduling n flows in a round robin 
> manner like this: "Each turn, one flow is served and n-1 packets are 
> dropped" frame as "Each turn, one flow is served and the other n-1 
> flows wait." And then you have the fair queueing approach which 
> already well exists. And which you reject because it would be too 
> expensive.

Emmanuel Lochin
Professeur ISAE - OSSI
Institut Supérieur de l'Aéronautique et de l'Espace (ISAE)
Issu du rapprochement SUPAERO et ENSICA
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Tel : 05 61 33 91 85 - Fax : 05 61 33 91 88
Web : http://personnel.isae.fr/emmanuel-lochin/
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