[Bug 1014] SCP slow bandwidth with Solaris8 on n240

[bugzilla-daemon at mindrot.org]

http://bugzilla.mindrot.org/show_bug.cgi?id=1014


dtucker at zip.com.au changed:

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------- Comment #4 from dtucker at zip.com.au  2005-10-26 18:20 -------
Created an attachment (id=1013)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=1013&action=view)
Increase SSH2 channel window, based on HPN-SSH patch

I think I've figured out what's going on here.  My guess is that when you
failover interface is in active mode, there's some kind of delay passing
received packets back up the stack.  (Maybe this would show up in pings of the
active interface?)

Currently, OpenSSH doesn not handle SSHv2 connections with a significant
bandwidth-delay product very efficiently, since they are throttled by the size
of the SSH2 channel windows.

This would explain why it doesn't happen with sshv1 (there's no channels, so no
channel buffer limits) and doesn't happen when you 'push" data (the acks would
be delayed, but would have minimal effect on the throughput).

This would also mean that other things are be affected too, however your TCP
stack is covering up the problem pretty well.  If my back-of-the-envelope
calculations are correct, the delay is in the order of 50ms.

If you are still experiencing the problem, please try this patch.  It's a
stripped-down variant of PSC's high-performance networking patch
(http://www.psc.edu/networking/projects/hpn-ssh/) that should only affect the
area causing you the problems.




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