Checklist for Using Loopback Testing for SONET Interfaces

1. Create a Loopback

• 1. Create a Physical Loopback

Connect the transmit port to the receive port.

• 2. Configure a Local Loopback

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

2. Set Clocking to Internal

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

3. Verify That the SONET Interface Is Up

show interfaces so-fpc/pic/port

4. Clear SONET Interface Statistics

clear interfaces statistics so-fpc/pic/port

5. Check That the Received and Transmitted Path Trace Are the Same

show interfaces so-fpc/pic/port extensive

6. 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

7. Verify the Status of the Logical Interface

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

8. Ping the SONET Interface

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

9. Check for SONET Interface Error Statistics

show interfaces so-fpc/pic/port extensive

1. Create a Loop from the Router to the Network

[edit interfaces interface-name sonet-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 SONET Interface.