Alcatel-Lucent 7750 Configuration Manual page 494

Interfaces
NOTE: This command is not saved in the router configuration between boots.
The no form of this command disables the specified type of loopback.
Default no loopback
Parameters line — Places the associated port or channel into a line loopback mode. A line loopback loops frames
received on the corresponding port or channels back to the remote router.
internal — Places the associated port or channel into a internal loopback mode. A internal loopback loops
the frames from the local router back at the framer.
remote — Sends a signal to the remote device to provide a line loopback.
mdl
Syntax mdl {eic | lic | fic | unit | pfi | port | gen} mdl-string
no mdl
Context config>port>tdm>ds3
Description
This command configures the maintenance data link (MDL) message for a DS-3/E-3.
This command is only applicable if the DS-3/E-3 is using C-bit framing (see the framing (DS3) command).
The no form of this command removes the MDL string association and stops the transmission of any IDs.
Default no mdl
Parameters mdl-string — specify an MDL message up to 38 characters long on a DS-3.
eic — Specifies the equipment ID code up to 10 characters long.
lic — Specifies the equipment ID code up to 11 characters long.
fic — Specifies the ID code up to 10 characters long.
unit — Specifies the unit ID code up to 6 characters long.
pfi — Specifies the facility ID code up to 38 characters long.
port — Specifies the port ID code up to 38 characters long.
gen — Specifies the generator number to send in the MDL test signal message up to 38 characters long.
mdl-transmit
Syntax mdl-transmit {path | idle-signal | test-signal}
no mdl-transmit [path | idle-signal | test-signal]
Context config>port>tdm>ds3
config>port>tdm>e3
Description This command enables the transmission of an MDL message on a DS-3/E-3 over channelized interface.
Page 494 7750 SR Interface Configuration Guide