perfsonar development work

[Sven Ubik <>]

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