Re: [Discussion] TCP Congestion Window (cwnd)

[Raghu Reddy <rreddy@xxxxxxx>]

Hi,

The following URL:

	<http://www.psc.edu/~web100/pathdiag/>

has a link to a tool called "Watchsender" that I believe does what you are 
looking for. Specifically, please see:

	<http://www.psc.edu/~web100/pathdiag/wscommand.html>

You can use this tool collect data from an open TCP connection, and the 
data is saved to a log file. Then you can use the same tool again to view 
any of the web100 variables from the log file.

The tricky part is about the getting Connection ID (CID) as quickly as 
possible, and there may be better ways of doing it than what is suggested 
on that web page.

Hope this helps!

--rr

--On Friday, January 28, 2005 6:26 PM +1000 Andrei Vishnevski 
<andrey@xxxxxxxxxxxx> wrote:

| Greetings all,
|
| I'm currently conducting a project related to TCP/IP performance over
| wireless links. One of the main problems I faced was getting a value of
| congestion window (cwnd) of the sender. It could be derived by analysing
| tcpdump output, but I wouldn't have 100% confidence in its correctness.
|
| I've successfully patched the kernel and installed userland tools. What I
| need is to get cwnd size every 0.01 second or even more frequently if
| it's possible, and output this information to the file. This file will be
| used later on for building graphs and establishing correllation between
| tcpdump output and changes in cwnd.
|
| I would like to know whether it's possible to collect cwnd information
| directly from /proc/web100? Or may be there is way of outputing this
| information to a file with the desired frequence with userland tools?
|
| Any suggestions will be appreciated.
|
| Yours Sincerely
| Andrei Vishnevski
|
| _______________________________________________
| Discussion mailing list
| Discussion@xxxxxxxxxx
| http://internal.web100.org/mailman/listinfo/discussion



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