Interesting problem

[Harold Hunt]

Mike,

I know one way to find out: try another network card :)

It could be software though, which you may be able to determine by looking
at your log files.  I'm pretty sure that when you do an 'ifconfig eth0
down', for example (on Linux), that the light on the switch does actually go
out.  When you run 'ifconfig eth0 up', the light comes back on.  I'm
wondering if, perhaps, the scripts that startup your machine are thinking
that the network card didn't initialize correctly (after a 2 second delay),
therefore the scripts downs the card and brings it back up again, ad
infinitum.  If that is the case, then there would probably be a message in
your log files.

Good luck,

Harold