Checklist for Using Loopback Testing for T1 Interfaces

1. Create a Loopback

• 1. Create a Physical Loopback

Connect a T1 loopback plug.

• 2. Configure a Local Loopback

[edit interfaces interface-name t1-options]
set loopback local
show
commit

2. Set Clocking to Internal

[edit interfaces interface-name]
set clocking internal
show
commit

3. Verify That the T1 Interface Is Up

show interfaces t1-fpc/pic/port

4. Clear T1 Interface Statistics

clear interfaces statistics t1-fpc/pic/port

5. Force the Link Layer To Stay Up

• 1. Configure Encapsulation to Cisco-HDLC

[edit interfaces interface-name]
set encapsulation cisco-hdlc
show
commit

• 2. Configure No-Keepalives

[edit interfaces interface-name]
set no-keepalives
show
commit

6. Verify the Status of the Logical Interface

show interfaces t1-fpc/pic/port
show interfaces t1-fpc/pic/port terse

7. Ping the T1 Interface

ping interface t1-fpc/pic/port local-IP-address bypass-routing count 1000 rapid

8. Check for T1 Interface Error Statistics

show interfaces t1-fpc/pic/port extensive

1. Create a Loop from the Router to the Network

[edit interfaces interface-name t1-options]
set loopback remote
show
commit

2. Create a Loop to the Router from Various Points in the Network

Perform Steps 2 through 8 from Diagnose a Suspected Hardware Problem with a T1 Interface.