It is possible that ports are changing from fabric to loop mode because one of the following events has occurred:
- A previously empty switch port has had a loop device, such as a tape drive, connected to it.
- A connected device has had its topology changed from fabric mode to loop mode.
- A fabric device has been removed from the switch port and has been replaced with a loop device.
The above scenarios are all dependant on the switch ports being in auto-sensing mode. If the ports are fixed to a certain topology and one of the above takes place, the switch ports will need to be manually altered to enable the switch to talk to the connected device.
This was first published in August 2009