On Wed, Nov 11, 2009 at 2:42 AM, Frank Schuster <frank.schuste...@web.de> wrote: > Hello, > > I did an iperf-test with an TCP windowsize on the serversite of 32768 Bytes > (iperf -s -w 32768) > The client use the command: iperf -c ip-address -t 1 -l 32768 -w 32768. > > I sniffer the data flow with (tshark/wireshark) and there I can see that the > server offers a windowsize in maximum of 47712!
You don't mention the OS, but from your previous emails to the iperf and netperf lists, I suspect that you're runnnig on Linux. If so, be aware that Linux doubles the requested socket buffer / TCP window sizes for resource accounting reasons. So when an application requests a 32KB socket buffer, the kernel actually allows up to 64KB. This is a fairly well known quirk of the Linux stack. The Linux TCP window auto-tuning is quite good, and in general it is best not to try to manually tune the window size. Eg, it is often best to avoid specifying the -w argument on Linux. Drew ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Iperf-users mailing list Iperf-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/iperf-users
