perfsonar development work

[Stephan Kraft <>]

Hi Sven,

our office is closed during holidays, so we haven´t a chance to answer
your questions. Next week, we all will be back (or in Cambridge) to
solve the problems.

Hope Verena will answer them.

Thanks and happy new year,

Stephan

Sven Ubik schrieb:
> Hi,
> 
> tried bwctl installation at 
> http://www.win-labor.dfn.de/bwctldemo/bwctl_demo.php
> 
> and I have a few questions or notes:
> 
> 1) What is difference between:
> 
> "Buffer size (in byte) (Size of read/write buffer for udp)" and
> "Window size (in byte) (Size of tcp window / udp socket receive buffer)"
> 
> Window size does not have sense for UDP (which is mentioned on the second
> line). And you can never set window size for TCP, it is a dynamic property
> of TCP protocol. You can only set the upper limit of socket buffers, which
> then determine the upper limit of window size.
> 
> On the other hand, you can also set the volume of data sent by the
> application at once, which can affect resulting throughput.
> 
> Is the above mentioned "buffer size" what you set by sysctl or
> setsockopt() or the resulting real buffer size after internal adjustments
> in Linux kernel (which also depends whether it is 2.4 or 2.6)?
> 
> What are default values?
> 
> 2) I tried first:
> 
> Prague IPv4 -> Amsterdam IPv4 and I got:
> 
> BWCTL Error: bwctl: Unable to connect to 192.87.102.210: Connection
> refused
> 
> then I tried Paris -> Athens and I got:
> 
> BWCTL Error: bwctl: Unable to connect to 194.177.210.70: Connection
> refused
> 
> then I tried Paris -> Rome and I got:
> 
> BWCTL Error: RECEIVER START RECEIVER END
> 
> then I tried Sofia -> Zagreb and I got:
> 
> BWCTL Error: bwctl: Unable to connect to 193.198.229.166: Connection
> refused
> 
> then I tried Amsterdam ->  Athens for UDP (previous tests were for TCP)
> and I got:
> 
> SOAP error:
> HTTP Error: Couldn't open socket connection to server
> http://192.87.102.210:8090/, Error (111): Connection refused
> 
> then I tried Gent -> Ljubjjana for UDP and I got:
> 
> BWCTL Error: RECEIVER START 3376807663.317963: iperf -B 193.2.63.2 -P 1 -s
> -f b -m -p 5001 -u -t 10
> 
> I did not find any combination that works.
> 
> 3) When I do one measurement and go back to do another measurement, all
> items in the form are lost and I have to fill in everything again. Is it
> possible to remember the latest values?
> 
> 4) When I find that throughput was low between some two points, do I get
> any feedback, that allows me to determine why it was low?
> 
> Regards,
> 
> Sven
> 


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Dr. Stephan Kraft                              Tel: +49 9131 85-28735
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