slow ssh connections on LAN

[dsr at tao.merseine.nu (dsr at tao.merseine.nu)]

On Mon, Jul 10, 2006 at 10:40:26PM -0400, Robert La Ferla wrote:
> 
> What kind of throughput is typically of a "scp" on a 100BaseT LAN?
> 
> ssh is encrypting the data, but is that really slowing the transfer  
> rate down?  The encryption algorithm does add overhead to the amount  
> of data to be transferred and it surely slows down the CPU.  This  
> will affect the final transfer time but shouldn't affect the transfer  
> rate much.

On any close-to-modern CPUs with files larger than a few megabytes apiece,
you should be able to get full wire speed -- SCP should report
something near 9-10 MB/s.

> What tools can I use to diagnose network performance issues (other  
> than ping)?  Ethereal?

You can test end-to-end bandwidth with httperf, iperf,
pathchar... take a look at
http://www.caida.org/tools/taxonomy/perftaxonomy.xml

-dsr-

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