[e2e] Why do we need congestion control?

[Detlef Bosau]

I could even extend my scenario with, say, PC 5 to PC 20 and TCP flows 
(bidirectional) from PC 5 to PC 7 etc. up to PC 18 to PC 20.

In other words: I can increase the load. Hence, an individual flow's 
throughput / goodput will be decreased.

Perhaps, this should be commonplaces here.

However, I hardly find this in many papers or even less in simulations. 
(E.g. I never really understood/believed the Ethernet-simulation in the 
NS2.....)

Am 10.04.2013 17:21, schrieb Detlef Bosau:
>
>>> Let me sketch a very simple scenario here.
>>>
>>> Think of four nodes, e.g. PC, attached to a simple coax Ethernet.
>>>
>>>                     PC 1                  PC 2             PC 
>>> 3                 PC 4
>>>                       |                     | |                    |
>>>
>>> -----------------------------------------------------------------------
>>>
>>> Think of two bidirectional TCP flows here.
>>>
>>> One betwenn PC 1 and PC 3, the other between PC 2 and PC 4.
>>>
>>>
>>> And now allow me to ask some questions.
>>>
>>> Q1: What do we want to achieve at all in this scenario? With 
>>> particular respect to the categories
>>>       - goodput
>>>       - throughput
>>>       - congestion avoidance
>>>       - fairness?
>>>
>>> Q2: Do we need VJCC in this scenario?
>>>
>>> Q3: Which of the goals stated in response to Q 1 are achieved?
>>>
>>> Q4: If goals are achieved, refer to Q3, what is the particular 
>>> contribution of VJCC here?
>>>
>>> This scenario is quite easy - and when I answered this questions for 
>>> myself, it became clear that I simply asked the wrong question when 
>>> I asked how many flows would fit into the Internet.
>>>
>>> To some degree, VJCC is a stroke of genius - while being a kludge at 
>>> the same time.
>>>
>>> So, I would like to ask: What are our goals? What do we achieve? Did 
>>> we achieve our goals? And is that what we achieve identical to our 
>>> intentions in the first?
>>>
>>>
>>>
>>>
>>>
>>> -- 
>>> ------------------------------------------------------------------
>>> Detlef Bosau
>>> Galileistraße 30
>>> 70565 Stuttgart                            Tel.:   +49 711 5208031
>>>                                            mobile: +49 172 6819937 
>>> Ich sehe nur den Klappentext zu Hetze-Rita:
>>>
>>>                                            skype: detlef.bosau
>>>                                            ICQ: 566129673
>>> detlef.bosau at web.de http://www.detlef-bosau.de
>>>
>
>


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Detlef Bosau
Galileistraße 30
70565 Stuttgart                            Tel.:   +49 711 5208031
                                            mobile: +49 172 6819937
                                            skype:     detlef.bosau
                                            ICQ:          566129673
detlef.bosau at web.de                     http://www.detlef-bosau.de