Hello everybody,
i’m experiencing a very poor performance using a leased line of 155Mbps and a RTT of 270ms between the endpoints… The transfer is by ftp… I’m not able to use more than 3/4 Mbps for single transfering… I already set the tcp Window size of the sender(sles11) and receiver (sles10), setting default tcp_wmem and tcp_rmem equal to BDP ( around 11MB). i set on both sides the max_tcp_rmem and max_tcp_wmem to 16M… i enabled on both sides the Window scaling, the timestamp using, i also increase the txqueuelen of the sender network driver, but nothing change… I tried to disable the autotuning of the receiver, and i tried also to increase the initcwnd of the sender to avoid slow start at the begin…
I also replicated that behaviour using two virtual server and adding a delay by “tc” Linux command…
I capture a dump using wireshark and i tried to analyze that using tcptrace… It seems that sender’s congestion window doesn’t increase even if the receiver advertised window is great almost like BDP …
Could somebody help me to set the optimal setting to permit full-capacity trhoughput of the link using one single transfer?
How can I attach you wireshark dump and the sysctl params of sender/receiver?
Thanks for your great help!
Br.
Paolo