Table of Contents

Troubleshooting the IGX

This chapter describes how to diagnose problems. When a troubleshooting table in this chapter recommends replacement, refer to the procedures in Chapter 5, "Replacing Parts on the IGX."

The IGX operating system software does most of the IGX monitoring and maintenance. The only action that qualifies as preventive maintenance is checking the power supplies.

Checking AC Power Supplies

You cannot directly measure voltages on the AC power supplies in an IGX node. If a problem exists with one of the supplies, one or both the DC and AC LEDs goes off. Refer to "Replacing Parts on the IGX," for instructions on reseating or replacing an AC power supply.

After you install new or additional cards in the node, check the LEDs on the power supplies to make sure that the cards have not put an excessive load on the power supplies.

Troubleshooting an IGX Node

This section describes elementary troubleshooting procedures and briefly describes the commands used when troubleshooting an IGX node. (These commands are described in detail in the Cisco WAN Switching Command Reference.) This set of procedures is not exhaustive and does not take into account any of the diagnostic or network tools available to troubleshoot the IGX node.

Caution    Do not perform any disruptive tests or repairs to the IGX node without first calling the Technical Assistance Center (TAC). For further information, refer to the "Obtaining Technical Assistance" section.

This section contains the following topics:

General Troubleshooting Procedures

The IGX node regularly runs self-tests to ensure proper function. When the node finds an error condition that affects operation, it deactivates the affected card or line then selects a standby card or redundant line if one is available.

Caution    A FAIL LED that comes on on a card indicates that an error occurred. Try resetting the light with the resetcd f command. If the FAIL LED comes on again, use the table below to find the cause or call the Cisco TAC to obtain information on isolating the problem and possibly replacing a component. For information on contacting the Cisco TAC, see the "Obtaining Technical Assistance" section.

Troubleshooting the IGX Console Alarms

The initial mode of troubleshooting the IGX node uses the console alarms displayed on the console screen.This section provides you with a procedure for isolating the alarms and thereby isolating the fault. Any repair to the IGX node must be performed by personnel qualified by Cisco.

Isolating Alarm Faults

Caution   Contact the Cisco TAC before performing any disruptive testing or attempting to repair the IGX node, to ensure that you have isolated the correct problem area and to enable Cisco personnel to provide you with assistance in performing the necessary procedures. For more information, refer to the "Obtaining Technical Assistance" section.

When a MAJOR/MINOR alarm flashes on the console screen, complete the following steps to determine the probable cause of the alarm:

Step 2   Use vt command to place yourself at the affected node, and use the dspalms command to identify the alarm type.

Troubleshooting Failed Connections

Step 2   Use the dsplog command to determine the cause of failure of the connections. These failures could consist of failed circuit lines, trunks cards, or clock overspeeds.

Troubleshooting Failed Circuit Lines

Troubleshooting Circuit Line Local or Remote CGAs

Step 2   Determine if the PBX T1 subrate or the PBX E1 interface went down at the time the CGA alarm was logged by the IGX node.

Step 3   Check cabling between IGX node and the PBX and make necessary repairs, if defective.

Step 4   Make a note of the steps taken and call the Cisco TAC (see the "Obtaining Technical Assistance" section).

Troubleshooting Circuit Line Frame Slips

Step 2   Use the dspclnerrs command to quantify frame slips and rate information.

Step 3   Use the dspclnhist command to obtain historical information on frame slips.

Step 4   Use the dspcurclk command to identify the current clock source and path to the current clock source.

Step 5   Use the clrclnalm command to clear the circuit line alarms

Step 6   Make a note of the steps taken, and call the Cisco TAC (see the "Obtaining Technical Assistance" section).

Troubleshooting Circuit Bipolar Errors

Step 2   Use the dspclnerrs command to quantify the bipolar errors.

Step 3   Use the dspclnhist command to obtain historical information on bipolar errors.

Step 4   Check cabling between IGX node and the PBX for loose connections, and tighten it if it is loose.

Step 5   Use the clrclnalm command to clear line alarms.

Step 6   Make a note of the steps taken, and contact the Cisco TAC. For more information, refer to the "Obtaining Technical Assistance" section.

Troubleshooting Failed Trunks

Troubleshooting Communication Failure and CGAs

A Local CGA indicates no pulses at the local end of the trunk; a remote CGA indicates no pulses at the remote end of the trunk.

Step 2   Use the dsptrkerrs command at each end of the packet line to quantify errors, and determine if they are unidirectional or bidirectional.

Step 3   Call telephone carrier and request span testing. Ask the carrier to perform BER tests using multiple test patterns, including standard quasi, all 1, and 3 and 24 patterns.

Step 4   Make a note of the steps taken, and contact the Cisco TAC. For more information, refer to the "Obtaining Technical Assistance" section.

Troubleshooting Bipolar Errors, Frame Slip Errors, and Out-of-Frame Errors

A bipolar error indicates excessive bipolar errors on the trunk. a frame slip error indicates excessive frame slips on the trunk. An out-of-frame error indicates excessive out-of-frame errors on the trunk.

Step 2   Use the dsptrkerrs command at each end of the trunk to quantify errors, and determine whether they are unidirectional or bidirectional.

Step 3   Use the dsptrkhist command at each end of the trunk to collect historical information on line errors.

Step 4   Use the clrtrkalm command to clear trunk alarms.

Step 5   Contact the Cisco TAC for assistance. Cisco personnel can monitor line errors and might advise disruptive testing to be scheduled with the telephone carrier. For more information, refer to the "Obtaining Technical Assistance" section.

Step 6   Call the telephone carrier and request span testing. Ask the carrier to perform bit error rate (BER) tests using multiple test patterns, including standard quasi, all 1, and 3 and 24 patterns.

Step 7   If the telephone carrier is unable to isolate the problem on the span, contact Cisco TAC for assistance. For more information, refer to the "Obtaining Technical Assistance" section.

Troubleshooting Packet Drops

Time-stamped and non-time-stamped packet drop errors indicate that packet drops have exceeded the threshold for generating an alarm.

Step 2   Use the dspload command alarm to determine the current loading of this trunk.

Step 3   Make a note of steps taken and call Cisco TAC. For more information, refer to the "Obtaining Technical Assistance" section.

Troubleshooting a Loopback

Step 2   If company personnel are performing loopback tests, ask them to indicate when they have completed testing, and monitor the system to ensure that the loopback indication disappears when testing is complete.

Step 3   If company personnel are not performing loopback tests, the telephone carrier most likely has the E1 span in loopback mode.

Step 4   Call the telephone carrier to verify that they are testing the E1 span, and ask them to indicate when they have completed their tests. Monitor the system to ensure that the loopback indication disappears when testing is completed.

Step 5   Make a note of the alarm steps taken, and call Cisco TAC. For more information, refer to the "Obtaining Technical Assistance" section.

Troubleshooting Failed Cards

Step 2   Use the dsplog command to determine the time of day the card failed and whether or not any connections using this card are also in a failed condition.

Step 3   If the failed card is an HDM or LDM card, use the dspbob command at each end of the connection, using this card to verify that data is passing. For a CDP, CVM, or UVM, use the dspchstats command.

Step 4   If a card has failed, make a note of the steps taken, and call Cisco TAC (see the "Obtaining Technical Assistance" section).

Troubleshooting Unreachable Nodes

Step 2   Contact personnel at that node to determine if there was a power failure at the time logged by the IGX node.

Step 3   If there was a power failure, check that NPM comes up, and run diagnostics.

Step 4   If there was not a power failure, call Cisco TAC. For more information, refer to the "Obtaining Technical Assistance" section.

Troubleshooting Clock Over Speed

Step 2   Use the dspcon command to verify that the console incoming baud rate is the same as the configured baud rate.

Step 3   Reconfigure the incoming baud rate to match the configured baud rate.

Step 4   Make a note of the steps taken, and call Cisco TAC. For more information, refer to the "Obtaining Technical Assistance" section.

Displaying a Summary of Alarms

The first step in troubleshooting an IGX node is to check the condition of the system by displaying alarm conditions throughout the system. To see a summary of all the alarms on an IGX node, use the dspalms (display current node alarms) command. The alarms summary includes the following:

To display alarms, enter the dspalms command.

If the screen indicates a failure, refer to the commands in Table 4-1 to further isolate the fault.

Displaying the Status of Cards

When a card indicates a failed condition on the alarm summary screen, use the dspcds command to display the status of the cards on a node. The information displayed for each card type includes the slot number, software revision level, and card status. (Note that you cannot use dspcds in a job.)

Note   If the dspcds command or any other command incorrectly states the IGX model (for example, stating that an IGX 8420 node is an IGX 8430 node), check the jumper switch W6 on the SCM. A jumpered W6 indicates an IGX 8420 node. An open W6 indicates an IGX 8430 node. Chapter 4, "Installing the IGX," documents this aspect of the SCM.

Table 4-2 lists all possible dspcds command status descriptions for all card types, including CVM.

Note   Cards with an "F" status (nonterminal failure) are activated only when necessary (for example, when there is no card of that type available). Cards with a failed status are never activated.

To display cards, issue the dspcds command. The dspcds command cannot be included in a job. Refer to the Cisco WAN Switching Command Reference for more information.

User-Initiated Tests

Several user commands help you test the node status. The CLI commands are:

For details on these commands, see the Cisco WAN Switching Command Reference.

Loopback Tests

Loopback tests are available to help diagnose the state of the IGX system. The CLI commands for activating these tests are:

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 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 "Moving a Node."

For software configuration and service provisioning information, see the Cisco IGX 8400 Series Provisioning Guide, "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 ."