Searching the net I have found several references to TCP stalls in
Linux,
especially when using PPP. So far this problem does not seem to have
been
solved, it is usually dismissed as noise and occasional losses over the
link.
I have performed some tests using various networks to try and understand
this problem.
My tests involved transferring a large file (1.2M) from an ftp servers
onto
a portable PC. I used three different machines for the ftp server, an
UltraSPARC running Solaris 2.6, an UltraSPARC running Linux 2.1.120 and
a
portable PC running Linux 2.0.32. The ftp client was always on Linux
2.0.32.
I captured packets on both the server and client, using snoop for
Solaris,
and tcpdump for Linux. I then used tcptrace to analyses the results.
The portable PC was connected to the backbone LAN using a GSM (mobile
phone)
connection over PPP. Similar results were obtained using a standard
modem and
a wireless network.
It appears the TCP congestion control in 2.1.120 is broken. A full
description
and the results are at:
http://www1c.btwebworld.com/hiperlan/m3a/technology/tcpstalls.html
Regards,
Richard
-- Richard Titmuss Email: richard@b29net.bt.co.uk B55 Rm122, BT Laboratories Martlesham Heath Tel: +44 (0)1473 640306 Ipswich, Suffolk, IP5 3RE, UK Fax: +44 (0)1473 646885- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/faq.html