This section describes how to identify problems, and suggests possible solutions. Flow diagrams have been used to summarize the process, and each step shown in the flow diagrams is described in more detail in the text.

This section assumes that the following conditions have been met:

• The ATM Module has been installed correctly, as described in "Installing And Setting Up The Module".

• The device is "alive" when pinged, and can be accessed through the local management screens.

• Both the ATM Module and the ATM Switch or attached ATM device are using the same physical standard; either SONET STS-3c or SDH STM-1.

Figure D-1 Troubleshooting Flow Diagram

The numbered steps in this section relate to the numbered steps shown in Figure D-1.

Access the Physical Layer Statistics Screen

a .   Select the SWITCH MANAGEMENT option from the Main Menu. The Switch Management screen is displayed.

b .   Ensure that the Port option is selected in the Management Level field.

c .   Ensure that the ATM port number is entered in the
Port ID field. For example the ATM port is:

• Port 7 on Switch 3000 FX

• Port 9 on Switch 3000 TX 8 Port

• Port 13 on Switch 1000 (12 port),
  Switch 3000 10/100,
  Switch 3000 TX 12 Port

• Port 25 on Switch 1000 (24 port) and
  Desktop Switch (24 port)

d .   Select the STATS button. The ATM Port Statistics screen is displayed.

e .   Select the PHYSICAL button to display the SONET or SDH physical layer statistics. An example of the Physical Layer Statistics screen is shown in Figure D-2.

Figure D-2 ATM Physical Layer Statistics

Are there Physical Layer Errors?

a .   If the OCD State field is set to Fail, there is a problem with the physical connection.

b .   If there are a lot of errors, there is a problem with the physical connection.

Is the error rate high?

Yes - go to step 3.

No - go to step 4.

Check the Physical Connections

Check that the Link Status and Far End Status LEDs on the ATM Module are ON and lit green. If one or both of the LEDs is not lit, there is a problem with the physical connection. Follow the troubleshooting information below:

a .   Ensure that both devices are powered-up, and that the ports at both ends of the link are enabled.

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

c .   Check each end of the cable to ensure that each of the fiber connectors is correctly connected. If your connectors can be reversed, you may need to reverse the TX and RX cable connectors at one end of the link.

d .   Remove any objects obstructing the cable and straighten out any kinks in the cable.

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

f .   Check that your cable meets the specifications described in "ATM Cable Specification".

g .   Replace the cable with a cable known to be working, and check the Link Status LED again.

h .   If there is still a problem, contact your repair center for advice. For more details, see "Support from 3Com".

Access the ATM Port Setup Screen

a .   Select the SWITCH MANAGEMENT option from the Main Menu. The Switch Management screen is displayed.

b .   Ensure that the Port option is selected in the Management Level field.

c .   Ensure that the ATM port number is entered in the
Port ID field. For example the ATM port is:

• Port 7 on Switch 3000 FX

• Port 9 on Switch 3000 TX 8 Port

• Port 13 on Switch 1000 (12 port),
  Switch 3000 10/100,
  Switch 3000 TX 12 Port

• Port 25 on Switch 1000 (24 port) and
  Desktop Switch (24 port)

d .   Select the SETUP button to display ATM port setup information. An example of the The ATM Port Setup screen is shown in Figure D-3.

Figure D-3 ATM Port Setup Screen

Is the ATM Port Enabled?

Is the Port State field set to Enable?

Yes - go to step 7.

No - go to step 6.

Enable the ATM Port

a .   Set the Port State field to Enable.

b .   Select the OK button.

Access the ATM Port Statistics Screen

a .   Select the SWITCH MANAGEMENT option from the Main Menu. The Switch Management screen is displayed.

b .   Ensure that the Port option is selected in the Management Level field.

c .   Ensure that the ATM port number is entered in the
Port ID field.

d .   Select the STATS button. The ATM Port Statistics screen is displayed. An example of the Port Statistics screen is shown in Figure D-4.

Figure D-4 ATM Port Statistics

Are Cells being transmitted and received?

ATM generates a continuous stream of cells. If the ATM port has been set up correctly, you should always see cells being transmitted and received on the ATM port (regardless of whether you are transmitting or receiving data).

Check the Cells Received and Frames Transmitted statistics to see if there is ATM traffic on the connection.

Is there ATM traffic on the port?

Yes - go to step 9.

No - Contact Technical Support.

Access the ATM VLAN LEC Status Screen

a .   From the Main Menu select the SWITCH MANAGEMENT option. The Switch Management screen is displayed.

b .   Ensure that the Port option is selected in the Management Level field.

c .   Ensure that the ATM port number is entered in the
Port ID field.

d .   Select the STATS button. The ATM Port Statistics screen is displayed.

e .   Select the LEC button to display the ATM VLAN LEC Status screen. An example of the ATM VLAN LEC Status screen is shown in Figure D-5.

Figure D-5 ATM VLAN LEC Status Screen

Is the LEC ATM Address Valid for the Default VLAN?

Check that the ATM address in the LEC ATM Address field is valid. For example, if the first part of the address (the network prefix) is all zeros the ATM Switch has not registered the ATM Module's LEC.

You can confirm that the ATM address of the LEC for the default VLAN is registered by checking the registered address table on the adjacent ATM Switch.

Is the ATM address valid and registered with the ATM Switch?

Yes - go to step 22.

No - go to step 11.

Is the ATM Switch Using AAL5?

It is very unlikely that your network has been configured to use incompatible devices, but to rule out the possibility, check that the ATM Switch uses the AAL5 protocol.

Does the ATM Switch also use AAL5?

Yes - go to step 13.

No - go to step 12.

Both Devices Must be AAL5 Compliant

The ATM Module is compatible with AAL5 ATM devices. If the ATM Switch connected to the ATM Module does not support AAL5, you will not be able to get the two devices to communicate. Re-configure your network to ensure that the ATM devices are compatible.

Is ILMI Turned On?

Some devices enable you to turn the Interim Local Management Interface (ILMI) on and off. ILMI on the ATM Module is set to ON and cannot be configured through the local management screens.

Check the user guides that accompany your ATM Switch, to see if you can configure ILMI, and check to see if it is turned on.

Is ILMI turned on at the ATM Switch?

Yes - go to Step 15.

No - go to Step 14.

Turn ILMI On

Turn ILMI on at the ATM Switch. Refer to the user guide that accompanies your ATM Switch.

Access the ATM Module Configuration Screen

From the Main Menu select the ATM CONFIGURATION option. An example of the ATM Module Configuration screen is shown in Figure D-6.

Figure D-6 ATM Module Configuration Screen

Is Signalling Compatible?

Signalling must be the same on both devices, and must be either 3.0 or 3.1. The default on the ATM Module is 3.1.

Is the Signalling compatible?

Yes - go to 18.

No - go to 17.

Make Signalling Compatible

Ensure that the Signalling mode is the same on the ATM Module and the ATM Switch.

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 .

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. 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 3Com 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.

Why has the LEC Operation Failed?

There are two fields on the ATM VLAN LEC Status screen, described in step 9, that can be used to troubleshoot LEC failure problems. The LEC Operation at Failure field identifies the operation that was taking place when the LEC failed to successfully join the Emulated LAN Services. The Last LEC Failure Reason field identifies the probable cause of the problem.

Use Table D-3, in conjunction with Table D-4to try and resolve the problem.

Table D-3 LEC Operation at Failure

Operation	Description
None	There are no known operation failures.
Calling LECS	The LEC is trying to connect to the LECS to receive LANE configuration information.
Reading Configuration from LECS	The LEC receives configuration information from the LECS in preparation for joining the LES.
Joining LES	The LEC is trying to join the ELAN by registering itself with the LES that controls that ELAN. When the LEC has joined the LES, it is given a unique LAN Emulation Client Identifier (LECID), knows the Emulated LAN's maximum frame size, and knows its LAN type (either Ethernet or Token Ring).
Initial Registration	After joining, a LEC can register any number of MAC addresses and/or Route Descriptors (for Token Ring implementations).
Connecting to BUS	In order to establish a connection to the Broadcast and Unknown Server (BUS) the LEC requires the broadcast address. It requests the broadcast address from the LES.
Operational	The LEC is now part of the ELAN.

Table D-4 Last LEC Failure Reason

State	Possible Causes	Possible Solutions
None	The LEC is either inactive or has successfully completed the operation.	None required.
Timeout A task could not be completed within its allotted time frame.	The software has been set up to use a LECS, but a LECS is either not present on the network or broken.	If there is a LECS on your network, ensure that it is operational and on part of the network that can be accessed by the ATM Module. If a LECS is not present on the network, you must enter the LES Address for each ELAN manually using the ATM VLAN Setup Screen (see "Extending VLANs into the ATM Network").
	The LES for the ELAN is not functioning correctly	Contact Technical Support.
Undefined Error An error has occurred but no cause can be identified.	Unknown.	Contact Technical Support.
Version Not Supported LANE 1.0 not supported.	The LANE services you are trying to connect to, do not support LANE version 1.0.	Ensure that the LANE Services use LANE 1.0.
Invalid Request Parameters The LES/LECS has rejected a request from the LEC because the request parameters were incompatible with the ELAN.	The LEC may be requesting a resource that is on an ELAN which has a different LAN type to the LEC.	Check the underlying media for both the ELAN and the LEC requesting the service.
	The frame size used could be wrong.	Check the frame sizes being used.
Duplicate LAN Destination A destination source MAC address duplicates a previously registered MAC address.	The LES has received a request from a LEC which contains a MAC address already registered to another LEC on the same ELAN. You may have accidentally entered the same MAC addresses twice.	Ensure that MAC addresses are unique.
Duplicated ATM Address A source ATM address duplicates a previously registered ATM address.	The LES has received a request from a LEC which contains an ATM address already registered to another LEC on the same ELAN. For example, if a LES is faulty, when a LEC disconnects from the LES, the LES might fail to register the change. When the LEC tries to rejoin the LES, the LES still has that LEC's ATM address in its database, and thinks that two devices have the same ATM address. You may have accidentally entered the same ATM addresses twice.	Ensure that ATM addresses are unique. Check the LES database for duplicate addresses.
Insufficient Resources There are insufficient resources to grant a request.	Too many connections have been requested and the tables used by the LES may be full, and the connection cannot be set up.	You may wish to consider extending or restructuring your network.
	The ATM Switch is busy and cannot provide LECS functionality.	Use a separate ATM Switch for LECS functionality.
	There is a mismatch between the VPI/VCI range supported by adjacent ATM devices. 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.	Make the MAX VPI/VCI Bits compatible.
Access Denied The LES has denied the LEC access to the ELAN for security reasons.	The LEC is trying to join an ELAN that it is not allowed to access.	Check your LANE Services setup.
Invalid Requestor ID The LEC Identifier (LECID) is not zero, or is not recognized as this LEC's LECID.	There is a problem with the LEC software.	Contact 3Com Support.
Invalid LAN Destination You are trying to register a multicast address with the LES.	You may have configured an illegal Local Administration Address.	Check that the Local Administration Address is valid. Local Administration Address setup is beyond the scope of this guide.
Invalid ATM Address Source or destination ATM address is not in a recognized format.	The ATM address field may have been corrupted or not in the correct format. For example, it may be in E.164 when OSI N-SAP address coding is required.	Contact your supplier or 3Com Technical Support.
No Configuration The LECS/LES does not recognize the LEC or the requested ELAN	The MAC address may be invalid.	Check that each MAC address on your network is unique.
	The LEC may be requesting a resource that is on an ELAN which has a different LAN type to the LEC.	Check the LAN type used.
	You may have entered an invalid ELAN name.	Check that the ELAN name is correct, and the ELAN has been set up correctly.
LE_CONFIGURE Error This state may be given to refuse a service without giving a specific reason.	The information provided by the LEC may be invalid.	As this state is used to indicate a range of problems, you should check the other states and solutions described in this table. If this does not resolve the problem contact 3Com Technical Support.
	You may have entered an invalid ELAN name.	Check that the ELAN name is correct, and the ELAN has been set up correctly.
Insufficient Information The LEC has not provided sufficient information to allow the LECS to assign it to a specific ELAN.	The MAC address may be invalid.	Check that each MAC address on your network is unique.
	The LEC may be requesting a resource that is on an ELAN which has a different LAN type to the LEC.	Check the LAN type used.
	You may have entered an invalid ELAN name.	Check that the ELAN name is correct, and the ELAN has been set up correctly.

Is the LEC Operational Now?

Yes - Go to step 25.

No - Contact Technical Support. Refer to "Technical Support".

Has the Problem been Solved?

Yes - No further action is required.

No - There may be a configuration problem with your network, see "ELAN Configuration Problems".

ELAN Configuration Problems

Figure D-7 shows a flow diagram to help you resolve problems associated with Emulated LAN (ELAN) configuration. The steps shown in the flow diagram are described in detail in the following text.

Figure D-7 ELAN Configuration Flow Diagram

Are the LECs on the Same Emulated LAN?

Check that the LECs on the ATM devices that wish to communicate are on the same Emulated LAN, and that they are on the same LAN technology. If the LECs are not on the same ELAN and LAN type, they will not be able to communicate (except through the use of a routing protocol).

Are the LECs on the same ELAN and LAN type?

Yes - go to step 3.

No - go to step 2.

Re-map or Route the LEC

Devices will not be able to communicate with each other if they are on different ELANs or use different LAN types, for example, if one device is on a Fast Ethernet LAN and the other is on a Token Ring LAN.

Check that you really wish the end-devices to communicate with each other and that they use the same LAN type. If the answer is yes you should either move one of the LECs or use routing, as described below:

Move one of the LECs
Move one of the LECs onto the same ELAN as the other LEC. On the ATM Module you can assign a LEC to a different ELAN as follows:

a .   Select the ATM CONFIGURATION option from the Main Menu. The ATM Module Configuration screen is displayed, as shown in Figure D-6. Select the
ATM LEC SETUP button.

An example of the ATM LEC Setup screen is shown in Figure D-8.

b .   Select the VLAN associated with the LEC that you wish to move.

c .   Either enter the ATM address of the LES that the LEC is going to join, or select LECS.

d .   In the ELAN name field, enter the name of the ELAN that the LEC is now to join and select the APPLY button.

Figure D-8 ATM VLAN LEC Setup

Use routing
Devices on one Emulated LAN can only communicate with devices on another Emulated LAN using routing protocols. Routing is outside the scope of this user guide. Consult the user guide that accompanies your router.

Is the MAC Address in the Switch Database?

If the MAC Address of a device connected to an Ethernet port on the Switch is not entered in the Switch Database, none of the LECs on the Switch can act as a proxy for that device. All LE_ARP requests will fail to locate the MAC address, and the requesting LEC will not be able to map an ATM address to that MAC address.

If a LEC fails to map an ATM address to a MAC address, locate the device with that MAC address.

Is the MAC address in the Switch Database of the Switch connected to the device with that MAC address?

Yes - Go to step 5.

No - Go to step 4.

Enter the MAC Address in the Switch Database

There are several reasons why the MAC address is not in the Switch Database:

• The Switch Database is full.

• The entry may have timed-out.

• There may have been a problem with the physical connection between the device and the Ethernet port on the Switch.

Identify the problem, and ensure that the MAC address is added to the Switch Database.

Is There Still a Problem?

Yes - Contact Technical Support. Refer to "Technical Support".
No - No further action is required.