Loopback – Enterasys Networks X-Pedition XSR CLI User Manual
Page 76
T1/E1 & T3/E3 Commands
2-70 Configuring T1/E1 and T3/E3 Subsystems
Syntax
linecode {ami | b8zs | hdb3}
Syntax of the “no” Form
Return to the default linecode setting by using the no form:
no linecode
Defaults
•
T1 line: B8ZS
•
E1 line: HDB3
Mode
Controller configuration:
XSR(config-controller<xx>)#
Example
This example sets the T1 controller with ESF framing, and B8ZS line encoding:
XSR(config)#controller t1 1/0
XSR(config-controller
XSR(config-controller
loopback
For T1/E1 controllers only
This command implements loopback tests on a T1/E1/ISDN‐PRI subsystem. Typically, it is used
for diagnostic purposes although you can configure an IP address as a loopback interface as
shown in the example. If you configure a loopback address for the XSR, it will be used as the
Router ID. If there is no loopback address defined, the Router ID is the highest non‐zero IP
address of existing configured and active interfaces.
When a T1/E1/ISDN‐PRI line malfunctions, one troubleshooting option is to perform various
loopback tests, for instance, isolating pieces of the link to test separately. Loopback testing should
begin on the local router and proceed to testing the service/network provider. Be aware that all
loopback testing is intrusive, and while loopback tests run, data transfers over the link are barred.
Syntax
loopback {diagnostic | local {line | payload}}
ami
Alternate Mark Inversion (AMI) line encoding.
b8zs
Bipolar 8 Zero Substitution (B8ZS) line encoding. Used for T1 controllers only.
hdb3
High‐Density Bipolar 3 (HDB3) line encoding. Used for E1 controllers only.
diagnostic
Loops the outgoing transmit signal back to the receive signal. Use the
show
t1/e1 controller
command to check if loopback is set. Use
show
interface serial
to verify that the channel groups are looped back.