[Soekris] Multi-unit routing throughput and ethernet speed issues

Stephen Milton milton at isomedia.com
Mon May 5 15:49:54 UTC 2003

Anyone else have problems with ethernet throughput when talking to
another Soekris?  I have a routing/ipsec testbed setup with a pair of
units that looks like this:

[Linux PC]<---->[4521-A]<++++>[4521-B]<---->[OSX Laptop]
  ^    ^          ^  ^          ^  ^          ^      ^
  |    |          |  |          |  |          |      |
  |    \--40Mb/s--/  \--13Mb/s--/  \--40Mb/s--/      |
  |                                                  |

<----> = Standard ethernet connection
<++++> = Reversed ethernet cable

I can get 40Mb/s from the Linux PC to 4521-A, and 40Mb/s from the OSX
laptop to 4521-B.  But I can only get 10-13Mb/s from 4521-A to 4521-B,
and only 7Mb/s from the OSX laptop to the Linux PC.

I have both 4521 Soekris units (current BIOS) running FreeBSD-4.8
stable, with HZ=2000 and DEVICE_POLLING enabled in the kernel.  They
both seem to sit with plenty of IO and CPU available during the
transfer.  I have tested the individual ethernet links at AUTODETECT
and hard-coded as 100BaseTX and FULL-DUPLEX.

It appears that the slow throughput comes from the Soekris unit back
to back connection.  I have tried different cables in that section,
as well as pushing it though a switch instead of short reversed cable.

I haven't seen anyone else doing quite this combination of testing,
but I am trying to calculate the maximum throughput through multiple
tower hops.

Any suggestions?  TIA.

Stephen Milton - Co-Founder                    (425) 881-8769 x102
ISOMEDIA.COM - Premium Internet Services        (425) 869-9437 Fax
milton at isomedia.com                        http://www.isomedia.com

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