[Babel-users] TCP "thin streams" optimisation in Linux

aaron aaron at lo-res.org
Mon Jan 10 03:44:35 UTC 2011


On Sun, Jan 09, 2011 at 07:57:55PM +0100, Juliusz Chroboczek wrote:
> Hi,
> 
> If you're using ssh logins over lossy networks (such as many mesh
> networks), you may be annoyed at the random delays you get after a loss
> event.  This is due to the fact that modern TCP is optimised for bulk
> transfer, and that it behaves badly in the presence of packet loss when
> there are less than 4 packets in flight.
> 
IMHO, you are tuning at the wrong place here... if your network connection is lossy, improve layer 1 and 2. As simple as that. And guaranteed to work :)
(and BTW this approach is even routing protocol agnostic ;-) 
Seriously, that is why we have a separation of network layers, that each can fulfill his duty (and layer 3 settings should not try to compensate for problems of the lower layers too much). If you are in a truly interesting environment such as delay tolerant networks, that is of course a whole different thing. 

But our practical experience shows: before you start to play around with settings like Juliusz proposed, consider to invest some extra cash into good Wi-Fi equipment (5GHz, good antennas) and improve layer 1 *first*.

my 2 cents,
OE1SYS




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