User`s guide

56 XSR User’s Guide
Troubleshooting T1/E1 Links Chapter 4
Configuring T1/E1 Interfaces
When a T1/E1 controller (port) is created with an associated channel group, it
can exist in three states:
 Administratively down:
If you do not enter the
no shutdown command when you create the
controller (port) or enter the
shutdown command for an already
created controller (port), you create all associated channel-groups on
that controller (port) but they are disabled.
 Down:
If you enter the
no shutdown command for the controller in
Controller mode, all associated channel groups are enabled on the
physical level but the controller senses an alarm on the line and will
not pass user data.
 Up:
Only when the associated interface is enabled using the
no shutdown
command in Interface mode does the channel-group become
operational. This is because there is one-to-one mapping between
channel groups and interfaces; if an interface is administratively
down so is its channel group - even if the controller port is up!
Follow these steps to restart the controller to correct this type of error:
1 Enter Controller mode. For example:
XSR(config)#controller t1 1/0
XSR(config-controller<T1/0>)#
2 Restart the controller:
XSR(config-controller<T1/0>)#no shutdown
If the T1/E1 controller and line are not up, ensure one of the following
messages appears in the
show controller output:
 Receiver has loss of frame (LOF), or
 Receiver has loss of signal (LOS)
Complete the following steps if the receiver has loss of frame:
1 Ensure the framing format set on the port matches the framing format
of the line. If needed, change the framing format configuration.
2 Change the Line Build-Out (LBO) using cablelength long and
cablelength short commands. If needed, contact your service
provider for more details on LBO configuration.