The XS716E Web Managed Switch supports loop detection, not prevention. When a loop is detected, both LEDs on the affected ports will blink at a constant speed of about 1 blink per second.
Loop detection is disabled by default, but you can configure it using either the web browser-based GUI or the ProSAFE Plus Utility.
For more information about configuring loop detection, see the ProSAFE 8-Port and 16-Port 10-Gigabit Web Managed Switch Models XS708Ev2 and XS716E User Manual.