Table of Contents
Chapter 4
Configuring the PA-A2 ATM CES Port Adapter
Checking the Configuration
Using loopback Commands
The loopback command places an interface in loopback mode, which enables test packets that are
generated from the ping command to loop through a remote device. If the packets complete the loop, the
connection is good. If not, you can isolate a fault to the remote device in the path of the loopback test.
The loopback diagnostic command on an ATM interface of a Cisco router causes traffic going out of the
interface to come back to the router.
If loopback is not set on the ATM interface, traffic will not be looped back. Traffic will go out but will
not return. Apply the loopback diagnostic command, and then use the show interface command to
show that loopback is indeed set:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# interface a1/0
Router(config-if)# loopback diagnostic
Router(config-if)# atm clock internal
Router(config-if)# ^Z
Router# show interface a1/0
ATM1/0 is up, line protocol is up
Hardware is A6 ATM
MTU 4470 bytes, sub MTU 4470, BW 155520 Kbit, DLY 80 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ATM, loopback set
Keepalive not supported
Encapsulation(s): AAL5, PVC mode
256 TX buffers, 256 RX buffers,
2048 maximum active VCs, 1024 VCs per VP, 1 current VCCs
VC idle disconnect time: 300 seconds
Last input 00:03:16, output 00:03:16, output hang never
Last clearing of "show interface" counters never
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
163861 packets input, 3164940 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
33 input errors, 33 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
144191 packets output, 2138298 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 output buffer failures, 0 output buffers swapped out
To ensure proper clocking, set the router as the clock source by specifying the atm clock internal setting
Note
in the main interface configuration.
The loopback line command on an ATM interface of a Cisco router causes incoming traffic to be sent
back to the network.
Router# config show interface a2/0
ATM2.0 is up, line protocol is up
Hardware is A6 ATM
MTU 4470 bytes, sub MTU 4470, BW 155520 kbit, DLY 80 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ATM, loopback set
Keepalive not supported
Encapsulation(s): AAL5, PVC mode
2048 maximum active VCs, 1024 VCs per VP, 1 current VCCs
PA-A2 ATM CES Port Adapter Installation and Configuration
4-19
OL3460-01
Table of Contents
