A TCP problem on High Delay

[bycn82]

Hi,
Yes, according to your pcap files,it is because of the window size.
more information here http://www.ietf.org/rfc/rfc1323.txt 
and share the result of "sysctl net.inet.tcp"

Regards,
bycn82



> -----Original Message-----
> From: owner-freebsd-net at freebsd.org [mailto:owner-freebsd-
> net at freebsd.org] On Behalf Of Niu Zhixiong
> Sent: 20 July, 2014 23:43
> To: freebsd-net at freebsd.org
> Subject: A TCP problem on High Delay
> 
> 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.
> 
> 
> 
> 
> ​
>  packet_capture.7z
> <https://docs.google.com/file/d/0By8sTL79ob4tTTBYQmhQT2Uxajg/edit?usp=dr
> ive_web>
> ​
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