How to loop the fiber optic cable on a switch

A hard loopback is performed on site using a physical fiber optic loopback adapter. This small device plugs directly into the switch port. Unlike standard patch cables that connect two different devices, a loopback cable creates a self-contained. Loopback testing involves sending a signal from a source back to itself, essentially creating a closed loop. In. Whether you are validating a new deployment or troubleshooting a dead port, the loopback cable is one of the most efficient tools in a network engineer's kit. [pdf]