loopback (SONET)
To configure the SONET controller for loopback mode, use the
loopback
command in SONET/SDH
configuration mode. To remove the loopback SONET command from the configuration file, use the
no
form
of this command.
loopback
{
internal| line
}
no loopback
{
internal| line
}
Syntax Description
Specifies that all the packets be looped back from the source.
internal
Specifies that the incoming network packets be looped back to the SONET network.
line
Command Default
This command is disabled by default.
Command Modes
SONET/SDH configuration
Command History
Modification
Release
This command was introduced.
Release 3.9.0
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes appropriate task
IDs. If the user group assignment is preventing you from using a command, contact your AAA administrator
for assistance.
The SONET and Synchronous Digital Hierarchy (SDH) transport layers support two loopback operation
modes for diagnostic purposes: internal and line. In the terminal (internal) loopback, the sent signal is looped
back to the receiver. In the facility (line) loopback, the signal received from the far end is looped back and
sent on the line. The two loopback modes cannot be active at the same time. In normal operation mode, neither
of the two loopback modes is enabled.
Examples
In the following example, all packets are looped back to the SONET controller:
RP/0/RSP0/CPU0:router(config)#
controller sonet 0/2/0/2
RP/0/RSP0/CPU0:router(config-sonet)#
loopback internal
Cisco ASR 9000 Series Aggregation Services Router Interface and Hardware Component Command Reference,
Release 5.3.x
872
SONET Controller Commands on the Cisco ASR 9000 Series Router
loopback (SONET)
