The current loopback state of the SONET/SDH interface. The
values mean:
sonetNoLoop
Not in the loopback state. A device that is not
capable of performing a loopback on this interface
shall always return this value.
sonetFacilityLoop
The received signal at this interface is looped back
out through the corresponding transmitter in the return
direction.
sonetTerminalLoop
The signal that is about to be transmitted is connected
to the associated incoming receiver.
sonetOtherLoop
Loopbacks that are not defined here.
Selects the source from which transmit timing is derived.
loop(1) indicates timing is recovered from the receiver;
internal(2) indicates timing is taken from the internal
system timing reference.