Juniper JUNOSE 11.1.X - COMMAND REFERENCE A TO M 4-9-2010 Command Reference Manual page 1298

JUNOSe 11.1.x Command Reference Guide A to M
Options
Controller Configuration, Interface Configuration
Mode
1256
loopback
local Loops the data back toward the router; on supported line modules also
sends an alarm indication signal (AIS) out toward the network.
network payload Loops the data toward the network after the framer has
processed the data.
network line Loops the data toward the network before the data reaches the
framer.
remote Sends a signal notifying the device at the remote end to activate or
deactivate the line loopback.
network Loops the data toward the network before the data reaches the framer.
payload Loops the data toward the network after the framer has processed the
data.
diagnostic Places the interface into internal loopback
line ATM interface: places the interface into external loopback; POS interface:
connects the received network signal directly to the transmit network signal.
When configured in line loopback mode, the router never receives data from
the network.
internal Connects the local transmitted signal to the local received signal