I've encountered this problem before and I believe it may affect other drivers (I could test but I don't have time). This was happening on my custom Linux system with the pcnet32 driver.
pcnet32: eth0: transmit timed out, status 97fb, resetting (and some other kernel module tracing in dmesg)
Basically it means the card is connected (it shows connected in full duplex etc.. and recognized if the cable is disconnected too) but no packets can be sent or received........
Apr 30 17:07:07 localhost kernel: [12265558.582378] r8169: eth0: link up
Apr 30 17:07:07 localhost NetworkManager: (eth0): carrier now ON (device state 1)
Apr 30 17:07:08 localhost kernel: [12265559.237961] r8169: eth0: link down
Apr 30 17:07:08 localhost NetworkManager: (eth0): carrier now OFF (device state 1)
Apr 30 17:07:11 localhost NetworkManager: (eth0): carrier now ON (device state 1)