Installation guide

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Cisco IGX 8400 Series Installation Guide, Release 9.3.3 and Later Releases
OL-1165-06
Chapter 4 Troubleshooting the IGX
Where to Go Next
Loopback Tests
Loopback tests are available to help diagnose the state of the IGX system. The CLI commands for
activating these tests are:
• CVM/NTM for implicit internal loopback.
• Vo ic e: addloclp, addrmtlp
• Data: addloclp, addrmtlp
• Frame relay: addloclp
For detailed information on these commands, see the Cisco WAN Switching Command Reference.
Card Testing with External Test Equipment
The HDM/SDI or LDM/LDI card set can be tested as a pair at the local node using external test
equipment such as a bit error rate tester (BERT). This can be useful in isolating “dribbling” error rates
to the cards, the Frame Relay data input, or the transmission facility. This test checks the data path from
the electrical interface at the port through the card set to the cellbus in both directions of transmission.
Note This is a disruptive test. Notify your network administrator before performing this test.
To perform this test, proceed as follows:
Step 1 Disconnect the cable connection to the SDI or LDI, and connect the BERT in its place.
Step 2 Set up an internal loopback on the Frame Relay port to be tested, using the addloclp command.
Step 3 Turn on the BERT, make sure that it indicates circuit continuity, and observe the indicated error rate.
Step 4 If there are any errors indicated, first replace the back card and retest. If the errors remain, then replace
the front card and retest.
Step 5 When the test is complete, disconnect the BERT and reconnect the data cable. Release the local loopback
by using the dellp command.
Step 6 Repeat at the node at the other end of the connection, if necessary.
Where to Go Next
For information on part replacement in the Cisco IGX 8400 series, see Chapter 5, “Moving a Node.”
For software configuration and service provisioning information, see the Cisco IGX 8400 Series
Provisioning Guide, Chapter 1, “Introduction to the Cisco IGX 8400 Series.”
For more information on switch software commands, refer to the Cisco WAN Switching Command
Reference, Chapter 1, “Command Line Fundamentals.”