SuperStack II Switch ATM OC-3c Module User Guide

Solving Known Problems

Use this section if you have already pin-pointed the problem, and wish to look up possible solutions. Solutions are presented as a series of tables, and each table relates to a logical problem area:

Power Supply problems
Power On Self Test (POST) failure
Cable connection problems
ATM problems
VLAN or ELAN problems

Power Supply Problems

Table D-5 Power Supply Problems

Problem

Possible Causes

Possible Solutions

Switch does not power up

Insufficient power supply to the Switch

System is not receiving power

Power supply malfunction

Blown fuse

If the Switch does not power-up correctly when the ATM Module is installed, you may require a different power supply. Refer to the Release Notes for information about 3Com power supplies.
Check that the power supply is plugged into the device and power outlet.
Check that the main power supply switch on the wall is set to the ON position.
Check, and if necessary change, the fuse. Refer to the user guide that accompanies your Switch for details about changing fuses and safety instructions.
Replace the power cable.
Contact 3Com Technical Support.

Switch powers up but then shuts itself down after a
few minutes

Insufficient power supply.

If the Switch powered-up correctly before the ATM Module was installed, there may be insufficient power available to power the Switch under heavy traffic conditions. Refer to the Release Notes.

Wiring closet is too hot
Vents are blocked
System fans are not operating

Check that the room temperature does not exceed
50°C (122°F), and that the Switch is positioned correctly so that it has adequate ventilation.
If the temperature exceeds the recommendations, lower the thermostat and wait for the room to reach the correct temperature range.
Restart the Switch. If the Switch turns itself off again, contact 3Com Technical Support.

Circuit breaker trips

External wiring problem
Power supply failure

Turn the Switch off.
Check with your local electricity supplier or company electrician that there is not an external electricity problem.
If you suspect the problem is caused by a 3Com device, contact 3Com Technical Support.

**Table D-5** Power Supply Problems
Problem	Possible Causes	Possible Solutions
Switch does not power up	Insufficient power supply to the Switch System is not receiving power Power supply malfunction Blown fuse	If the Switch does not power-up correctly when the ATM Module is installed, you may require a different power supply. Refer to the Release Notes for information about 3Com power supplies. Check that the power supply is plugged into the device and power outlet. Check that the main power supply switch on the wall is set to the ON position. Check, and if necessary change, the fuse. Refer to the user guide that accompanies your Switch for details about changing fuses and safety instructions. Replace the power cable. Contact 3Com Technical Support.
Switch powers up but then shuts itself down after a few minutes	Insufficient power supply.	If the Switch powered-up correctly before the ATM Module was installed, there may be insufficient power available to power the Switch under heavy traffic conditions. Refer to the Release Notes.
Wiring closet is too hot Vents are blocked System fans are not operating	Check that the room temperature does not exceed 50°C (122°F), and that the Switch is positioned correctly so that it has adequate ventilation. If the temperature exceeds the recommendations, lower the thermostat and wait for the room to reach the correct temperature range. Restart the Switch. If the Switch turns itself off again, contact 3Com Technical Support.
Circuit breaker trips	External wiring problem Power supply failure	Turn the Switch off. Check with your local electricity supplier or company electrician that there is not an external electricity problem. If you suspect the problem is caused by a 3Com device, contact 3Com Technical Support.

Power On Self Test (POST) Failure

Table D-6 Power On Self Test (POST) Failure

Problem

Possible Causes

Possible Solutions

Switch Fails Power On Self Test (POST)
MGMT LED is Yellow

The version of software on your Switch is not correct.
There is a hardware problem with the Switch.

Upgrade the version of software on the Switch.
Contact Technical Support.

ATM Module Fails Power ON Self Test (POST)
MGMT LED is Yellow flashing

The version of software on your ATM Module is not correct or has become corrupted.
There is a hardware problem with the ATM Module.

Upgrade the version of software on the ATM Module.
Contact Technical Support.

**Table D-6** Power On Self Test (POST) Failure
Problem	Possible Causes	Possible Solutions
Switch Fails Power On Self Test (POST) MGMT LED is Yellow	The version of software on your Switch is not correct. There is a hardware problem with the Switch.	Upgrade the version of software on the Switch. Contact Technical Support.
ATM Module Fails Power ON Self Test (POST) MGMT LED is Yellow flashing	The version of software on your ATM Module is not correct or has become corrupted. There is a hardware problem with the ATM Module.	Upgrade the version of software on the ATM Module. Contact Technical Support.

Cable Connection Problems

Table D-7 Cable Connection Problems

Problem

Possible Causes

Possible Solutions

Link Status LED indicates that there is a problem with a link.
Far End Status LED indicates that there is a problem with the ATM Module's transmit connection.

One or both of the ATM ports forming the connection are turned off (disabled).

Ensure that both ports are enabled.

The cable at either end of the link has become loose or accidentally disconnected.

Ensure that the cable is securely connected to the port at both ends of the link.

The two connectors at one end of the fiber cable may be plugged into the port the wrong way around.

Check each end of the cable to ensure that each of the fiber connectors is correctly connected. You may need to reverse the TX and RX cable connectors at one end of the connection.

The fiber optic is caught under a heavy object or become bent out of shape.

Remove any obstructions and straighten out any kinks in the cable.

The cable connector may be dirty.

If you suspect that the fiber optic connector is dirty, refer to "Cleaning Dirty Fiber Optic Connectors".

The cable may be broken.

Replace the cable, and check the LED again.

The connector itself is physically damaged.

Contact your repair center for advice. For more details, refer to "Support from 3Com".

**Table D-7** Cable Connection Problems
Problem	Possible Causes	Possible Solutions
Link Status LED indicates that there is a problem with a link. Far End Status LED indicates that there is a problem with the ATM Module's transmit connection.	One or both of the ATM ports forming the connection are turned off (disabled).	Ensure that both ports are enabled.
The cable at either end of the link has become loose or accidentally disconnected.	Ensure that the cable is securely connected to the port at both ends of the link.
The two connectors at one end of the fiber cable may be plugged into the port the wrong way around.	Check each end of the cable to ensure that each of the fiber connectors is correctly connected. You may need to reverse the TX and RX cable connectors at one end of the connection.
The fiber optic is caught under a heavy object or become bent out of shape.	Remove any obstructions and straighten out any kinks in the cable.
The cable connector may be dirty.	If you suspect that the fiber optic connector is dirty, refer to "Cleaning Dirty Fiber Optic Connectors".
The cable may be broken.	Replace the cable, and check the LED again.
The connector itself is physically damaged.	Contact your repair center for advice. For more details, refer to "Support from 3Com".

ATM Problems

Table D-8 ATM Problems

Problem

Possible Causes

Possible Solutions

The ATM Connection Table is only showing reserved ATM Connections
Symptoms:

The VLAN LEC Status screen, described in "ATM VLAN LEC Status", shows that the LEC is Inactive and there is no network prefix for the LEC ATM address.

The ATM Switch connected to the ATM Module is using a different VPI:VCI value for ILMI.

Check that the devices at both ends of the connection are using the same ILMI VPI:VCI.
Check version of signalling in use. The ATM Switch must use version 3.0 or 3.1 to be able to communicate with the ATM Module.

**Table D-8** ATM Problems
Problem	Possible Causes	Possible Solutions
The ATM Connection Table is only showing reserved ATM Connections Symptoms: The VLAN LEC Status screen, described in "ATM VLAN LEC Status", shows that the LEC is Inactive and there is no network prefix for the LEC ATM address.	The ATM Switch connected to the ATM Module is using a different VPI:VCI value for ILMI.	Check that the devices at both ends of the connection are using the same ILMI VPI:VCI. Check version of signalling in use. The ATM Switch must use version 3.0 or 3.1 to be able to communicate with the ATM Module.

VLAN or ELAN Problems

Table D-9 VLAN or ELAN Problems

Problem

Possible Causes

Possible Solutions

The configured LECs cannot communicate with each other
Possible symptom:
The Last LEC Failure Reasons, described in Table D-4 is LE_CONFIGURE or similar error type.

The devices that need to communicate are not in the same VLAN/ELAN.

Check that the ELAN name has been set up correctly.
Check LAN Emulation supported on the ATM Switch. The ATM Switch must use LAN Emulation Version 1.0.
Check that the correct VPI/VCI are used and that there they have not been mismatched. Refer to "Intermittent failure of a configured LEC to connect to the LECS or LES" below.
Ensure that both LECs are within the same VLAN/ELAN. LECs not in the same VLAN/ELAN can only communicate using a router.

Insufficient Resources

Excessive traffic is overloading the ATM device, and it does not have sufficient resources to assign new connections.

You may need to reconfigure or restructure your network. For example, you may wish to use a separate ATM Switch for LECS functionality.

A LEC requires a separate connection for each LEC with which it needs to communicate. If you try to bring up all of the connections at the same time, the ATM Module may run out of connections.

Do not try to bring up too many connections at the same time.
You may need to reconfigure or restructure your network.

Intermittent failure of a configured LEC to connect to the LECS or LES
Symptom:

Insufficient resource error message.
LECs fail but seem to automatically recover.

The MAX VPI Bits and MAX VCI Bits settings are incompatible between ATM devices. For example, if auto-
configuration is not enabled, and the MAX VPI/VCI Bits have been set up incorrectly.
Each ATM device supports a separate and sometimes different pre-set range of VPI/VCI values. When Signalling tries to set up the VPI/VCI values for a connection, it automatically suggests the next available value in a pre-set range of values supported by the source Switch.
If the adjacent ATM Switch does not support these values, it rejects the connection, and an insufficient resource error message is displayed.

Example:
If Switch A supports VPI/VCI values 7:511 and Switch B only supports values up to 7:255, when Signalling tries to set up a connection using the VPI/VCI value 7:256, Switch B rejects the connection.

Identify the connection that is causing the problem. The following steps should be carried out in order:
1 . Check that the MAX VPI/VCI Bits are compatible on the edge-device to ATM Switch User-to-Network interface (UNI).
2 . Check that the MAX VPI/VCI Bit settings are compatible on all devices between the edge-device and the LECS.
3 . Check that the MAX VPI/VCI Bit settings are compatible on all ATM devices between the LEC and the LES.
When you have identified the connection, manually reconfigure the VPI/VCI values to make them compatible.

**Table D-9** VLAN or ELAN Problems
Problem	Possible Causes	Possible Solutions
The configured LECs cannot communicate with each other Possible symptom: The Last LEC Failure Reasons, described in Table D-4 is LE_CONFIGURE or similar error type.	The devices that need to communicate are not in the same VLAN/ELAN.	Check that the ELAN name has been set up correctly. Check LAN Emulation supported on the ATM Switch. The ATM Switch must use LAN Emulation Version 1.0. Check that the correct VPI/VCI are used and that there they have not been mismatched. Refer to "Intermittent failure of a configured LEC to connect to the LECS or LES" below. Ensure that both LECs are within the same VLAN/ELAN. LECs not in the same VLAN/ELAN can only communicate using a router.
Insufficient Resources	Excessive traffic is overloading the ATM device, and it does not have sufficient resources to assign new connections.	You may need to reconfigure or restructure your network. For example, you may wish to use a separate ATM Switch for LECS functionality.
A LEC requires a separate connection for each LEC with which it needs to communicate. If you try to bring up all of the connections at the same time, the ATM Module may run out of connections.	Do not try to bring up too many connections at the same time. You may need to reconfigure or restructure your network.
Intermittent failure of a configured LEC to connect to the LECS or LES Symptom: Insufficient resource error message. LECs fail but seem to automatically recover.	The MAX VPI Bits and MAX VCI Bits settings are incompatible between ATM devices. For example, if auto- configuration is not enabled, and the MAX VPI/VCI Bits have been set up incorrectly. Each ATM device supports a separate and sometimes different pre-set range of VPI/VCI values. When Signalling tries to set up the VPI/VCI values for a connection, it automatically suggests the next available value in a pre-set range of values supported by the source Switch. If the adjacent ATM Switch does not support these values, it rejects the connection, and an insufficient resource error message is displayed. Example: If Switch A supports VPI/VCI values 7:511 and Switch B only supports values up to 7:255, when Signalling tries to set up a connection using the VPI/VCI value 7:256, Switch B rejects the connection.	Identify the connection that is causing the problem. The following steps should be carried out in order: 1 . Check that the MAX VPI/VCI Bits are compatible on the edge-device to ATM Switch User-to-Network interface (UNI). 2 . Check that the MAX VPI/VCI Bit settings are compatible on all devices between the edge-device and the LECS. 3 . Check that the MAX VPI/VCI Bit settings are compatible on all ATM devices between the LEC and the LES. When you have identified the connection, manually reconfigure the VPI/VCI values to make them compatible.

If you have problems that are not addressed by troubleshooting information in this guide, contact 3Com Technical Support, or your service person. For Technical Support information refer to "Technical Support".