Parameter: Loopback

The Loopback parameter is used to set the loopback state of a line service. Values for this parameter are selected from a drop-down list. The Loopback parameter can take on the following values:

Loopback Type	Description	Behavior	When shoud we use it?
NONE	Normal Operation	All traffic is received and sent on the line	Always
LINE	Analog Line Loopback	All received traffic is re-routed on the transmit line. The clock and data recovered from the line inputs are routed back to the line outputs of the analog transceiver bypassing the framer modules	First step in testing a physical connection
PAYLOAD	Digital Line Loopback	All received traffic is re-routed on the transmit line.The clock and data recovered from the line inputs are routed back to the line outputs after the deframer/framer.	Second step in testing a physical connection. This tests the framer configuration.
GENERATE_LOS	Generate Loss of Signal	This forces the transmit line to stop sending	This is the second-best thing to disconnecting the line interface physically.
LOCAL	Local Loopback	All received traffic is dropped. The traffic sent is re-routed internally.	Never. Used for internal testing only.

To change the Loopback parameter from the Web Portal:

Line Interfaces -> Line Services (Choose) -> Status Tab -> Loopback -> Apply States

To see the status from the Web portal:

Line Interfaces -> Status tab