[e2e] Are we doing sliding window in the Internet?

Detlef Bosau detlef.bosau at web.de
Mon Jan 1 04:48:19 PST 2007


Fred Baker wrote:
>
>
> I wonder where you got the notion that a typical session had a 10 ms 
> RTT. In a LAN environment where the servers are in the same
It´s just a number.  However, it´s the magnitude. Not the exact number. 
In your example below you have about 
20 ms,
100 ms,
200 ms
RTT.

If we again consider one outstanding segment with 12000 bit we have the 
following rates (approximately)
600 kbps
120 kbps
60 kbps

It´s not the question whether this is optimal. It´s the question: Does 
this happen in a relevant number of cases?
Particularly in downloads from mobile devices which quite often do not 
offer larger bandwidth.

So to your question why TCP should tune itself to only one outstanding 
segment: The reason could be the limited bandwidth the node, e.g. a 
mobile node, can handle.


Detlef




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