Troubleshooting and Conflict Resolution Tools

Troubleshooting a WLAN is sometimes more complex than double-checking WEP keys. Cisco includes with its client devices a helpful utility known as the Client Troubleshooting Utility. This section examines that tool and provides information about resolving common sources of client problems in a Windows environment.

Client Troubleshooting Utility

As with APs, there are some useful places to check first. Check to ensure that the radio is turned on. Many laptops use both hardware and software switches to turn off the radio. Do you also see a Link Status icon that indicates whether or not you have a connection? The problem might not have anything to do with an RF connection; it's more than likely a configuration issue.

Cisco includes a useful troubleshooting tool with its client utilities package. The Troubleshooting Utility enables you to find and fix problems on the client computer.

Note

The Troubleshooting Utility is meant for use only when the computer is in infrastructure mode and not ad hoc mode. This is because the utility is used to evaluate the connection between the client and an AP.

The following explains how you can use the Troubleshooting Utility. Again, the steps might vary depending on the model of wireless card you use. However, this should give you an idea of what to do and what to look for when using the tool:

Step 1.	Start the utility by opening ADU.
Step 2.	Click the Diagnostics tab, and then click Troubleshooting. The Troubleshooting Utility window appears.
Step 3.	Click Run Test. The utility performs seven tests to check client operation and connectivity: Driver installation test Card insertion test Card enable test Radio test Association test Authentication test Network test The utility runs, and then it shows the results for each test.

For each of the seven Troubleshooting Utility tests, different messages can appear in the Troubleshooting Utility window:

• Test passedThe test was successful.

• Test bypassedThe test was skipped because it was not necessary for the current operation.

• Test failedIf the test failed, click View Report to show detailed information about the test and why it was unsuccessful. Figure 13-4 shows an example of a report.

  Figure 13-4. The Cisco Client Troubleshooting Utility's Detailed Report View

  

  
  

Tip

If you choose to, you can save the report for later review by clicking Save.

Prioritizing Connections

If the client computer has more than one network adapter installed (for example, the client might have an Ethernet adapter in addition to an Aironet client card), you can establish which connections are attempted first by assigning priority to your network connections.

The following steps, used with Microsoft Windows, show how to prioritize network connections:

Step 1.	Right-click the My Network Places icon. This icon can be found either on your desktop or from the Start menu.
Step 2.	Click Properties.
Step 3.	Select Advanced from the menu at the top of the screen.
Step 4.	Click Advanced Settings. This shows your network connections in the Connections box on the Adapters and Bindings tab, as illustrated in Figure 13-5. Figure 13-5. Client Network Adapters Can Be Prioritized on Systems with More Than One Adapter
Step 5.	Use the arrow buttons next to the Connections box to prioritize your connections.
Step 6.	Click OK.

Note

Windows XP users might think there are problems with their connection when no problem exists. If a client adapter was configured using ADU, the Windows Wireless Network Connection icon in the system tray might be marked with a red X. This shows that the connection is unavailable. However, it is likely that the connection does, in fact, exist. This is caused by a conflict between the wireless network settings of ADU and Windows XP. You can ignore the Windows icon and instead use the Aironet System Tray Utility icon to verify the status of your wireless client adapter's connection. This seems to be much less of a problem with Service Pack 2, but it is still something to be mindful of.

Windows Resource Conflicts

Note

The following steps are used on Windows XP. The process is similar, but somewhat different, with different flavors of Windows.

You might run into trouble with a client adapter running on a Windows-based computer. You might occasionally encounter a situation in which a different interrupt request (IRQ) is necessary because of a device conflict. By default, IRQ 10 is used, which might not be compatible with all systems. To change the IRQ setting, follow these steps:

Step 1.	Double-click My Computer and then click Control Panel > System.
Step 2.	Click the Hardware tab, and then click Device Manager. The resulting window is shown in Figure 13-6. Figure 13-6. Windows Device Manager
Step 3.	Under Network Adapters, double-click the Cisco Systems Wireless LAN Adapter. This is shown in Figure 13-7. Figure 13-7. Details of the Cisco Wireless Adapter
Step 4.	The Device Status field shows if there are any resource problems. If one exists, click the Resources tab. This is shown in Figure 13-8. Figure 13-8. The Resources Tab Can Be Used to Resolve Hardware Conflicts
Step 5.	Uncheck the Use automatic settings check box.
Step 6.	Under Resource Settings, click I/O Range.
Step 7.	In the Conflicting Device list, check to see if the range is used by another device, and then click the Change Setting button.
Step 8.	Choose a range that does not conflict with the device. The Conflict Information pane at the bottom of the window shows if the range is already being used.
Step 9.	Click OK.
Step 10.	Under Resource Settings, click IRQ.
Step 11.	Examine the Conflicting Device list at the bottom of the window. If an IRQ setting is used by another device, click the Change Setting button.
Step 12.	Choose an IRQ in the Value dialog box and select one that does not conflict with the device. The Conflict Information pane at the bottom of the window shows if the IRQ is already being used.
Step 13.	Click OK.
Step 14.	Reboot your computer. (This is required.)

As you have seen in this and previous chapters, wireless networks combine many of the issues germane to a wired network, along with the specialized characteristics of radio transmission and reception. Successfully troubleshooting these networks requires you to balance the two disciplines.