The switch ports on the Cisco routers don’t appear to be as robust as a standard switch.  All clients at a clients motor bank went down the other morning.  After travelling on site, it turned out the problem was a bad cable end on one client.  All seven devices connected to the same 8-port switch on the branch router, and this one bad cable took down all seven devices.  I could move the faulty device from the router’s switch port to an external switch, and everything would work.  I went ahead and replaced the bad cable end, and reconnected all devices to the router’s switchports.