Command Reference Guide

250 ● loopback (CT1/PRI Interface) 3Com Router 5000 Family and Router 6000 Family
Command Reference
loopback (CT1/PRI Interface)
Purpose Use the loopback command to enable a CT1/PRI interface to perform local, remote,
or external payload loopback.
Use the undo loopback command to disable the CT1/PRI interface to perform
loopback.
Syntax loopback { local | remote | payload }
undo loopback
Parameters local
Enables the CT1/PRI interface to perform local
loopback.
remote
Enables the interface to perform remote loopback.
payload
Enables the interface to perform external payload
loopback.
Default By default, the interface is disabled to perform loopback in any form.
Example Set the interface T1 1/0/0 to perform remote loopback.
[3Com -T1 1/0/0] loopback remote
View This command can be used in the following views:
■ CT1/PRI Interface view
Description You can use loopback to check the condition of interfaces or cables. When they are
operating normally, disable this function.
You can bundle timeslots on the CT1/PRI interface to form a serial interface and
encapsulate it with PPP. After you enable loopback on this serial interface, it is normal
that the state of the link layer protocol is reported down.