TCP-Window

[Florian Prester <Florian.Prester --at-- rrze.uni-erlangen.de>]

Hi,

I try to analyze the bandwidth of a network:

I am connected through a 56k modem (which should be the bottleneck) and 
the ping is 156ms.

Calculation of the window:
      
    56000bit/sec * 156sec /1000 = 56 bit * 156 = 8736 bit / 8 = 1092Byte

->  Windowsize: 1kByte

Am I correct?

My problem:
   
    The test results are quite ok: bandwidth: 25-35kbits

But, if I am increasing the WindowSize to 2k I get bandwith of 
50-60kbits and with 64k up to 80kbits (which is more than my modem can do).
Is this all because of compression?

How should I determ a suitable windowsize? The dokumentations say the 
theoretical value (bottleneck * RTT) is to be in- e.g. decreased a bit, 
to play around. But increasing and decreasing with 1kByte <-> 2kByte and 
the duplication of the Bandwidth is quite confusing.


Thanks,

Florian





-- 
--------------------------------------------------------------
Dipl. Inf. Florian Prester
Network Administration
Regionales RechenZentrum Erlangen
Universitaet Erlangen-Nuernberg
Germany

Tel.: +499131 8527813