Adjusting TCP windows on production systems?

Steve Francis steve at expertcity.com
Tue Sep 30 22:27:28 UTC 2003


Marshall Eubanks wrote:

>On Tue, 30 Sep 2003 15:44:03 -0400
> "Temkin, David" <temkin at sig.com> wrote:
>  
>
>>Is there anyone in a production environment who, as part of their system
>>build process, adjusts the TCP receive window/MSS/etc. on production
>>systems?
>>
>>    
>>
As a concrete data point:
the tuning below on Solaris 9 increased the TCP data transfer rates from 
SJC to NYC by a factor of 10:
(i.e. from 2 to about 20Mbps with ftp; 1 to 11Mbps with scp.)

ndd -set /dev/tcp tcp_recv_hiwat 400000
ndd -set /dev/tcp tcp_xmit_hiwat 400000 
ndd -set /dev/tcp tcp_wscale_always 1
ndd -set /dev/tcp tcp_max_buf 10485760






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