Use Loopback Testing for ATM Interfaces

This chapter describes the steps for using loopback testing to isolate Asynchronous Transfer Mode (ATM) interface problems. The steps for loopback testing apply to both ATM1 and ATM2 intelligent queuing (IQ) interfaces. (See Table 21.)

Table 21: Checklist for Using Loopback Testing for ATM Interfaces

ATM Interface Loopback Testing Tasks	Command or Action
Diagnose a Suspected Hardware Problem with an ATM1 or ATM2 IQ Interface
Create a Loopback
Create a Physical Loopback	Connect the transmit port to the receive port.
Configure a Local Loopback	[edit interfaces interface-name (sonet-options | t3-options)] set loopback local show commit
Set Clocking to Internal	[edit interfaces interface-name] set clocking internal show commit
Verify That the ATM Interface Is Up	show interfaces at-fpc/port/pic
Clear ATM Interface Statistics	clear interfaces statistics at-fpc/port/pic
Ping the ATM Interface	ping interface at-fpc/port/pic local-IP-address bypass-routing count 1000 rapid
Check for ATM Interface Error Statistics	show interfaces at-fpc/port/pic extensive
Diagnose a Suspected Circuit Problem
Create a Loop from the Router to the Network	[edit interfaces interface-name (sonet-options | t3-options)] set loopback remote show commit
Create a Loop to the Router from Various Points in the Network	Perform Steps 2 through 6 from Diagnose a Suspected Hardware Problem with an ATM1 or ATM2 IQ Interface.