# loopback

#### Syntax

For module controllers, the options available vary depending on the module being configured.

CT3 module:

loopback { local | network | payload }

no loopback

[ no ] loopback remote

cOCx/STMx SONET controller (SONET/SDH section layer), OCx/STMx line modules:

loopback { local | network }

no loopback

COCX-F3 module:

loopback { local | network | payload }

no loopback

For interfaces; the options available vary depending on the interface being configured.

ATM interface (cannot be used on a subinterface):

loopback { diagnostic | line }

no loopback

POS interface:

[ no ] loopback { internal | line }

#### Release Information

Command introduced before JunosE Release 7.1.0.

#### Description

Specifies the loopback mode for a module controller or interface. The no version clears all loopback on the module or interface (the default), or deletes the mapping to the user domain name.

| Note: In Domain Map Configuration mode, this command has been replaced by the local-interface command and may be removed completely from Domain Map Configuration mode in a future release.

#### Options

- 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

#### Mode

Controller Configuration, Interface Configuration