Re: How to use TCP window autosizing?

[Dave Huang <khym%azeotrope.org@localhost>]

So it turns out NetBSD's TCP window autosizing works fine after all...
apparently the problem is scp. I was able to get about 6Mbytes/s
throughput by transferring the file via HTTP. While the file is
transferring via HTTP, netstat on the remote Linux end shows about 4MB
in the "Send-Q". Whereas while it's transferring via scp, netstat
shows only 32K or so in the Send-Q.

According to http://www.psc.edu/index.php/hpn-ssh , "SCP and the
underlying SSH2 protocol implementation in OpenSSH is network
performance limited by statically defined internal flow control
buffers." I'm not too sure why I was able to get OK performance using
PuTTY's pscp on Windows, but that page also says, "HPN clients will be
able to download faster from non HPN servers." Perhaps PuTTY doesn't
have the same bottleneck as OpenSSH, so it's able to download faster
even with the slow sshd.

Looks like pkgsrc openssh has an option for the HPN patch--I'll give
that a try, and see if I can find something similar for the Linux
side.
-- 
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