A TCP problem on High Delay

[Niu Zhixiong]

Dear All,
    I set up an FTP server in a high delay but fairly BW environment.
    When I try to download files from this FreeBSD FTP server, A FreeBSD
client is always slower than Linux Client. (Linux Client is about 1MB/s,
But FreeBSD client 300KB/s). I am sure that the two clients are in same
networks and no firewalls are between server and clients. Then I try to use
SCTP protocol rather than TCP protocol. The FreeBSD client is faster than
itself in TCP.

I try to increase the rbuff of the client. But, It always less than the
linux one. I think the problem may be the smaller window of Freebsd than
Linux. But, I changed some parameters. But, nothing changed.

uname -a
10.0-RELEASE FreeBSD 10.0-RELEASE #0 r260789: Thu Jan 16 22:34:59 UTC 2014
    root at snap.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64

According to
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-kernel-limits.html

I try to enable sysctl net.inet.tcp.inflight.enable or sysctl
net.inet.tcp.inflight_enable , but there is no such option in FreeBSD 10.

Then I follow this https://fasterdata.es.net/host-tuning/freebsd/
And make a large rbuffer.


sysctl   kern.ipc.maxsockbuf=16777216
sysctl   net.inet.tcp.sendbuf_max=16777216
sysctl   net.inet.tcp.recvbuf_max=16777216
sysctl  net.inet.tcp.sendbuf_auto=1
sysctl  net.inet.tcp.recvbuf_auto=1
sysctl   net.inet.tcp.sendbuf_inc=16384
sysctl   net.inet.tcp.recvbuf_inc=524288
sysctl   net.inet.tcp.hostcache.expire=1

But, Nothing is happened.

In the attachments, l_f is the linux packet capture and f_f is the freebsd
packet capture.




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 packet_capture.7z
<https://docs.google.com/file/d/0By8sTL79ob4tTTBYQmhQT2Uxajg/edit?usp=drive_web>
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