Table of Contents

Checking Basic LANE Configuration
Checking LANE Client Configuration

Troubleshooting LAN Emulation Switching Environments

This chapter provides troubleshooting information for connectivity and performance problems in LAN emulation (LANE) switching environments. The ATM Forum defined the LANE specification so that legacy LAN users can take advantage of the benefits of ATM without requiring modifications to end-station hardware or software. For an overview of LANE on a switch router, refer to the "Configuring LAN Emulation" chapter in the ATM Switch Router Software Configuration Guide . For an overview of LANE on the Catalyst 5000 and 6000 ATM modules, refer to the "Configuring ATM LAN Emulation" chapter in the ATM Software Configuration Guide and Command Reference : Catalyst 5000 and 6000 ATM Modules.

Before you begin, make sure that all physical port connections are working correctly. See "Troubleshooting Switch Router ATM Interface Connections."

This chapter contains the following sections:

Example of LANE Troubleshooting

This section describes LANE troubleshooting, using the example network in Figure 6-1 and in "Example Network."

A single emulated LAN consists of a 155 multimode fiber physical connection between the switch router (EngFl1Ls1) and the Catalyst 5000 Fast Ethernet switch (EngFl1Cas1) in the engineering building. The switch router is configured as the LAN emulation configuration server (LECS), the LAN emulation server (LES), and the LAN emulation broadcast-and-unknown server (LANE BUS).

The LANE example network for the engineering building in Figure 7-1 is configured as follows:

Initial Troubleshooting of LANE

This section describes how to use the Internet Control Message Protocol (ICMP) ping command to test for connectivity between the switch router and either a router or an Ethernet switch.

To test for Ethernet connectivity, perform the following task:

Follow these steps to troubleshoot LANE connections:

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

Step 2   Check the Success rate field. It should indicate 100 percent. This indicates that the ICMP packet was sent and returned.

If the success rate is less than 100 percent, continue with the following test to determine the problem with the LANE configuration. Refer to the "Configuring LAN Emulation" chapter in the
ATM Switch Router Software Configuration Guide .

Checking Basic LANE Configuration

Use the following commands to test the LANE connection status and performance:

Follow these steps to confirm the LANE LECS, LES, and BUS configuration:

Step 2   Use the show lane command to confirm the LANE configuration of the switch router.

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Note    This example show how to confirm the LANE configuration of a switch router. Use the same command to confirm the LANE configuration of a Catalyst 5000 or 6000 ATM module.

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Admin: up State: operational

ATM Address of this LECS: 47.00918100000000E04FACB401.00E04FACB405.00 (auto)

LE Server ATM13/0/0.1 ELAN name: eng_elan Admin: up State: operational

ATM address: 47.00918100000000E04FACB401.00E04FACB403.01

LE BUS ATM13/0/0.1 ELAN name: eng_elan Admin: up State: operational

ATM address: 47.00918100000000E04FACB401.00E04FACB404.01

Step 3   Check the Admin (Administration) and State fields. The values should be up and operational, respectively.

Step 4   Check the ATM address of this LECS field. This ATM address should match the ATM address in the LANE configuration server displayed in Step 1.

Step 5   Within the LE BUS section of the display, check the ELAN name field. It should match the name configured. To determine the ELAN name, use the show lane database command and check the default ELAN field.

Step 6   Check the ATM Address field. This ATM address should match the address displayed in the LANE Server field shown in Step 1. The ATM address is appended with the corresponding subinterface number in hexadecimal.

If any of these fields do not match the actual LANE configuration, refer to the "Configuring LAN Emulation" chapter in the ATM Switch Router Software Configuration Guide and correct the configuration.

Checking LANE Client Configuration

Use the following command to troubleshoot the LANE client connectivity:

Follow these steps to confirm the configuration and status of the LANE client:

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Note    This example shows how to confirm the LANE client configuration at ATM subinterface 13/0/0.1 on a switch router. Use the same command to confirm LANE client configurations on the Catalyst 5000 or 6000 ATM modules.

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LE Client ATM13/0/0.1 ELAN name: eng_elan Admin: up State: initialState

Join Attempt: 11

Last Fail Reason: Timeout on join request

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Note    This same information appears in the previously described show lane command.

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Step 2   Check the ELAN name field. This should match the ELAN name configured.

Step 3   Check the Admin and State fields. They should read up and operational, respectively.

If the Admin field shows "down", the interface or subinterface is administratively shut down. To reenable the interface, use the no shutdown command on the interface or subinterface.

Step 4   Check the Join Attempt field. A high number of join attempts might mean that the LECS is unreachable. To determine the status of the LECS, use the show lane config command.

Step 5   Check the Last Fail Reason field for any of the following messages:

The problem is on the physical layer. Check the cable and the module quality. Physically loopback the interface and check the status using the show interfaces command.

The switch detected a configuration change. Force the LANE client to join the ELAN with the shutdown/no shutdown command sequence on the interface or subinterface.

The LANE client cannot establish a VCC to the LECS. This failure might be caused by ILMI, which must be enabled to provide the ATM address prefix. If ILMI is not functioning, no ATM address prefix is distributed and no SVCs can be established. Check the LANE component addresses using the show lane default-atm-addresses command. The following example shows correct output:

If ILMI is not suppling the ATM address prefix, the output appears as follows:

Use the show atm ilmi-status command to verify that the ILMI PVC is well defined. For more information on configuring ILMI, refer to the "Configuring ILMI" chapter in the
ATM Switch Router Software Configuration Guide .

The LECS address is incorrect or unreachable. If the LANE client could not reach the LECS, the show lane client command output looks like the following:

Last Fail Reason: Config VC being released

   0 0 0 configure 47.007900000000000000000000.00A03E000001.00

Try the following actions to connect the LANE client with the LECS:

The LECS refuses to connect to the ELAN. This is usually due to a configuration mistake, such as incorrectly specifying the ELAN type or name. Try the following actions to resolve the problem:

The LANE client could not connect to the LES. The LES is either unreachable or misconfigured. If the LES address is hardcoded in the configuration, check the ATM address of the LES on the device where it is located, using the show lane server command. Compare that address with the ATM address configured for the LES on the LANE client switch, using the show lane database command.

The LES refuses to connect. Try the following actions to resolve the problem:

Step 6   Check the ATM Address column in the virtual channel circuit (VCC) configuration table. These ATM addresses should be propagated as follows:

Step 7   Confirm that the rxFrames and txFrames columns contain values greater than 0.

Checking the Configuration Server Database

The LECS assigns individual clients to particular emulated LANs by directing them to the LANE server that corresponds to the emulated LAN. The LECS maintains a database of LANE client ATM or Media Access Control (MAC) addresses and their ELANs.

Note   A LECS can serve multiple ELANs.

Use the following command in privileged EXEC mode to display the configuration of the LANE client database binding:

Follow these steps to confirm the configuration of the LANE database:

LANE Config Server database table 'eng_dbase' bound to interface/s: ATM13/0/0

  server 47.00918100000000E04FACB401.00E04FACB403.01 (prio 0)

Step 2   Check the LANE Config Server database table field. It indicates the binding of the LANE client to the LANE database.

Step 3   Check the server field. The ATM address displayed should correspond to the ATM address shown in the show lane default-atm-addresses command in Step 1 of the previous section, "Checking Basic LANE Configuration."

If the LANE client configuration server database is set up incorrectly, refer to the "Configuring LAN Emulation" chapter in the ATM Switch Router Software Configuration Guide .

Debugging the LANE Connection

This section outlines the debug commands used to troubleshoot the LANE setup and signalling.

Use the following debug commands to check the LANE configuration and setup processes:

Note   Other helpful debug commands include the debug atm ilmi command and all the variations of the debug atm sig command.

Posted: Wed Jan 22 00:20:19 PST 2003
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