Loop-back mode of the interface. When the loop-back mode is
changed to line(2) or dtm(3), a timer is initialized with the
value of itsIfLoopTime. The loop-back mode is reset to
none(1) when the timer runs out.
notSupported(0). Loopback is not supported by the
interface. This value can not be written.
none(1). The interface is not in loop-back mode. This is the
normal operation of the interface.
line(2). The interface is in loop-back mode on the line
side. Everything that is received on the Rx line interface is
looped back to the Tx line interface, and is also transmitted
to the remote node. Data received from the remote node is
ignored.
dtm(3). The interface is in loop-back mode on the DTM link
side. Everything that is received from the remote node is
looped back to the remote node, and is also output on the Tx
line interface. Data received on the Rx line interface is
ignored.