Checklist for Using Loopback Testing for Channelized DS3 Interfaces

To use loopback testing to isolate Channelized DS3 interface problems.

Table 47 provides the links and commands for using loopback testing for Channelized DS3 interfaces.

Table 47: Checklist for Using Loopback Testing for Channelized DS3 Interfaces

Tasks	Command or Action
Diagnose a Suspected Hardware Problem with a Channelized DS3 Interface
Create a Loopback
Create a Physical Loopback	Connect the TX port to the RX port.
Configure a Local Loopback	[edit interfaces interface name (t3-options \| t1-options)] set loopback local show commit
Verify That the Interface Is Up	show interfaces t1-fpc/pic/port:channel show interfaces t3-fpc/pic/port:channel
Clear Interface Statistics	clear interfaces statistics t1-fpc/pic/port:channel
Force the Link Layer to Stay Up
Configure Encapsulation to Cisco-HDLC	[edit interfaces interface-name] set encapsulation cisco-hdlc show commit
Configure No-Keepalives	[edit interfaces interface-name] set no-keepalives show commit
Verify the Status of the Logical Interface	show interfaces t1-fpc/pic/port:channel
Ping the Channelized Interface	ping interface t1-fpc/pic/port:channel local-IP-address bypass-routing count 1000 rapid
Check for Interface Error Statistics	show interfaces t1-fpc/pic/port:channel extensive
Diagnose a Suspected Circuit Problem
Create a Loop from the Router to the Network	[edit interfaces t1-fpc/pic/port:channel t1-options] set loopback remote show commit
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 Channelized DS3 Interface.