From: "Ulrik Lunddahl (PROconsult)" <ul at proconsult dot dk>

> I use the PC images in standard rack mount PC's

> This time i used Intel Gigabit adapters (PWLA8391GT), but i noticed
> dropouts more specific it looked like the adapters resets itself, because 
> my
> switch lost link for a sec or two, and then the connection was good again.

> I changed NICS, cables and so on, but the problem was still there, all i 
> got
> in the console was link down and then link up again in 2-10 seconds.

> I changed to 100 Mbit intel nics (PILA8460C3), same behavior but a lot
> more in the logs.

This first thing I would look for is IRQ conflicts.  Also, you might try 
different PCI slots.

                        Lee