- Enterasys Security Router User's Guide

Troubleshooting T1/E1 & T3/E3 Links
4-8 Configuring T1/E1 & T3/E3 Interfaces
Figure 4-3 T1/E1 & T3/E3 Physical Layer (Layer 1) Troubleshooting Flowchart
The show controller command displays current controller parameters, status and statistics data.
Most controller errors are caused by incorrectly configured lines including line coding, framing,
and clock source parameters.
When a T1/E1 or T3/E3 controller (port) is created with an associated channel or 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<T1-1/0>)#
If your T1/E1 or T3/E3 controller still
does not function as desired,
contact your service/network provider
Are the cables
Use the following commands to
bring up the controller:
controller t1 x
framing
Loss of Signal/Loss of Frame
No
and connectors
ok?
Loss of Signal
Loss of Frame
Connect or
replace the
cable
No
Yes
Is the
framing format
correct?
Use the following commands to
change the LBO:
cablelength long/short (T1)
cablelength (T3)
Yes