Sed
The Router recovered itself from this lost, so i maybe discard the Switch issue (just change port)
You can certainly discard the switch as your issue here, however it is the issue here.
Your NIC is not bad.
You don't need to clone mac's.
You asked...
Is there any way the the SME can detect these cuts and refresh the connection to our ISP?
Yes....connect SME directly to the modem.
or
Run the command below when you experience the symptom or reboot SME.
/sbin/e-smith/signal-event ip-change
The Router recovered itself from this loss
It's possible, however most of the time it will also need to be rebooted.
We are experimenting a lost in the connection to Internet from time to time.
You need to investigate the cause of the loss of connection.
Have you checked the signal levels to the modem, browse to your modem usually 192.168.100.1
Receive Power Level >5.0 and <15.0 dBmV
Transmit Power Level >45 and <50 dBmV
Call your ISP and ask them how many modem resets you've had in the last week.
The more resets the bigger the problem. Should have a couple each week 0-10 is OK.
5000+ resets means you have a poor signal or bad modem. Usually it's signal.
Who's your ISP and what model modem do you have.????