L Commands for Cisco DSLAMs with NI-2

Syntax Description

diagnostic	Transmit data is looped to receive data at the physical (PHY) layer. This option is available on all ports.
line	The external receive signal is looped to transmit at the PHY device. This option is available only on trunk and subtending ports (both OC-3 and DS3).
payload	The received payload stream is looped through the transmit stream. This option is available only on DS3 trunk and subtending ports.

Default

Disabled

Command Mode

Interface configuration

Command History

Release

Modification

 12.0(5)DA

 This command was introduced in a previousrelease.

Usage Guidelines

Enabling or disabling loopbacks does not untrain or retrain a port. However, removing a loopback does cause the port to retrain.

Examples

This command enables ATM local loopback for port 1 of slot 20, then disables the loopback:

DSLAM# configure terminal
DSLAM(config)# interface atm 20/1
DSLAM(config-if)# loopback diagnostic
DSLAM(config-if)# no loopback diagnostic
 

This command enables a line loopback for the trunk port:

DSLAM# configure terminal
DSLAM(config)# interface atm 0/1
DSLAM(config-if)# loopback line
 

Related Command