(fxp is the Intel 82588 Ethernet driver.) 

Anybody else seeing these?  What's going on? 

I'm trying to see how much traffic I can cram through a network.  
I get >90 megabits when running TCP in one direction.  Things get 
confused when I try to run (lots of) traffic in both directions. 

I'm running a point-point link between a pair of Alphas.  ifconfig 
says 
fxp0: flags=8c43<UP,BROADCAST,RUNNING,OACTIVE,SIMPLEX,MULTICAST> mtu 1500
        address: 00:08:c7:08:2a:91
        media: Ethernet autoselect (100baseTX full-duplex)
        status: active


It also happens if I force both ends to 100/FDX (rather than letting 
it autoselect) and in half duplex mode.