[e2e] Question the other way round:

[Joe Touch]

On 11/19/2013 10:09 AM, Dave Crocker wrote:
> On 11/19/2013 9:07 AM, Joe Touch wrote:
>>
>>
>> On 11/15/2013 1:42 PM, Detlef Bosau wrote:
>>> Why do we need congestion at all?
>>
>> No, but only if you use circuits. But then you've pushed the
>> "congestion" overload situation to the circuit setup time, and not all
>> circuits will succeed.
>>
>> Or you could be omniscient ;-)
>>
>> Otherwise, you need to deal with the fact that sometimes two packets
>> want to go to the same output port and can't, and you didn't find that
>> out until they collided.
>
>
>
> Given the complete generality of the question that was asked, is there
> something fundamentally deficient in the answer in:
>
>     http://en.wikipedia.org/wiki/Congestion_control#Congestion_control
>
> ?
>
> In particular, I think it's opening sentence is quite reasonable.

I agree, but it jumps in assuming packets. Given packets, it's easy to 
assume that oversubscription is the natural consequence of avoiding 
congestion.

But it isn't if you have a-priori known traffic patterns - as are 
increasingly common inside data centers, as well as for some past 
circuit use cases.

I.e., the opening sentence assumes that all congestion control is 
reactive. It can be proactive given the right information.

Joe