D-10APPENDIX D: TROUBLESHOOTING

Is the ILMI Connection Set Up Correctly?

To communicate with each other, edge-devices must use the same Interim Local Management Interface (ILMI) connection.

On the ATM Module the ILMI connection is specified in the ILMI VCC field, as shown in Figure D-6 on page D-9.

Consult the user guide that accompanies the ATM Switch to find out where the ILMI connection is specified.

Is the ILMI connection the same for the ATM Module and the ATM Switch?

Yes — go to step 20.

No — go to step 19.

Make ILMI VPI/VCI Same at Both Ends of the Link

Ensure that the ILMI VPI and VCI values are the same on both the ATM Module and the relevant ATM Switch port.

In most cases you should probably use the standard ILMI VPI/VCI values: VPI = 0, VCI = 16.

Are the MAX VPI and VCI Bits Compatible?

To communicate with each other, edge-devices must use compatible MAX VPI Bits and MAX VCI Bits settings. The MAX VPI Bits and MAX VCI Bits settings determine how many bits are used within each cell header to define the value of the VPI and VCI. The VPI and VCI values identify the connection.

Some ATM devices automatically negotiate the number of bits used for the VPI and VCI fields. In this situation you would only change the number of bits if you want to increase the number of bits used by both ATM devices.

On the ATM Module these settings are shown on the ATM Module Configuration screen, see Figure D-6 on page D-9. The default setting for MAX VPI Bits is 3, and 8 for MAX VCI Bits.

Refer to the ATM Switch user guide to find out how to locate these settings on your ATM Switch.

Are the settings compatible?

Yes — If you are still experiencing problems, contact Technical support.

No — go to step 21.

Make the MAX VPI and VCI Bits Compatible

Ensure that the MAX VPI Bits and MAX VCI Bits settings are compatible.

Is the LEC Operational?

Using the ATM VLAN LEC Status screen, described in step 9, check the Last LEC Failure Reason.

Is the Last LEC Failure Reason field set to None?

Yes — the LEC is operational. Go to step 25. No — go to step 23.

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IBM ATM OC-3c manual Is the Ilmi Connection Set Up Correctly?, Make Ilmi VPI/VCI Same at Both Ends of the Link