Cisco Systems OL-1377-03 User Manual
CHAPTER
7
Performing Diagnostics
This chapter describes the client utility tools that you use to assess the operation and performance of the
client adapter and the wireless network.
The following topics are covered in this chapter:
• Diagnostic Tools for Mac OS 9, page 7-2
• Diagnostic Tools for Mac OS X, page 7-10
• Site Survey, page 7-19
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Diagnostic Tools for Mac OS9
Diagnostic Tools for Mac OS 9
The pcm340PPC client utility provides tools that help you assess the performance of the client adapter
and other devices on the wireless network. ACU diagnostic tools perform the following functions:
• Display your client adapter’s current status and configured settings
• Run a link test to assess the operation of the RF link between your client adapter and its associated
access point
• Run a link test to assess the operation of the wired link between your access point and a wired device
• Obtain information about local access points (configured for broadcast SSID)
Viewing the Current Status of Your Client Adapter
To view your client adapter’s status, select the Status tab on the advanced properties screen. The Status
Screen appears (see Figure 7-1).
Figure 7-1 Status Screen
Chapter 7 Performing Diagnostics
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Table 7-3 on page 7-11 describes the status information.
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Chapter 7 Performing Diagnostics
Assessing the Wireless and Wired Links
You can determine the performance of the RF link between your client adapter and its associated access
point in two different ways:
• Youcan use thelink status meter(LSM) to viewa graphicaldisplay of thesignal strength and quality
of the client adapter’s radio signal. Go to the “Viewing the Link Status Meter” section below.
• You can run a link test that allows you to set the number and size of the packets to be transmitted
and then to determine the success or failure of those packets. Go to the “Running a Link Test”
section on page 7-4.
Viewing the Link Status Meter
To access the Link Status Meter screen, select Link Status Meter on the advanced properties screen.
The Link Status Meter screen appears (see Figure 7-2).
Figure 7-2 Link Status Meter Screen
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The Link Status Meter screen provides a graphical display of the following:
• Signal strength—The strength of the client adapter’s radio signal at the time packets are being
received. It is displayed as a percentage along the vertical axis.
• Signal quality—The quality of the client adapter’s radio signal at the time packets are being
received. It is displayed as a percentage along the horizontal axis.
The combined result of the signal strength and signal quality is represented by a moving bull’s-eye (see
Figure 7-2). Where the bull’s-eye falls on the graphical display determines the quality of the RF link
between your client adapter and its associated access point. Differences in the quality of the RF link are
indicated by the following colors: green (excellent), yellow (good), orange (fair), and red (poor).
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Diagnostic Tools for Mac OS 9
This information can be used to determine the optimum number and placement of access points in your
RF network. By using LSM to assess the RF link at various locations, you can avoid areas where
performance is weak and eliminate the risk of losing the connection between your client adapter and the
access point.
Selecting the Show History check box causes the graphical display to show a recent history of the RF
performance between your client adapter and its associated access point. Black dots on the graphical
display show the performance of the last 20 measurements. These black dots can be cleared from the
display by clicking the Clear History button.
Note The access point that is associated to your client adapter and its IP address are indicated at the bottom
of the display.
Running a Link Test
The client utility’s link test tool evaluates the operation of the RF link between your client adapter and
the associated access point. The test can also be used to check the operation of the wired link connected
to the access point. The link test sends out Ping packets to assess the operation of the link (RF link and
wired link) between your client adapter and the destination device specified by the IP address. The test
is usually performed multiple times at various locations throughout your area and is run at the data rate
displayed in the RF Settings section of the advanced screen (see the Data Rate parameter in the “Setting
RF Parameters” section on page 6-14). You can use the results of the link test to determine RF network
coverage and ultimately the required number and placement of access points in your network. The test
also helps you to avoid areas where performance is weak, thereby eliminating the risk of losing the
connection between your client adapter and its associated access point.
Chapter 7 Performing Diagnostics
Note A link test can also be run from an access point through a Telnet session. Refer to Chapter 4 of the Cisco
Aironet Access Point Software Configuration Guide for information.
The following prerequisites are required before you can run an RF link test:
• The TCP/IP protocol must be installed on your system.
• Your computer and the access point must have an IP address.
• Your computer must be configured to use the client adapter as its network interface.
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Chapter 7 Performing Diagnostics
Follow the steps below to run a link test.
Step 1 Select the Link Test tab on the advanced properties screen. The Link Test screen appears (see
Figure 7-3).
Figure 7-3 Link Test Screen
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Step 2 In the IP Address ofaccess point field, enterthe IP addressof the accesspoint or wireddevice withwhich
you want to test the link.
Note You can specify the IP address of a device on the wired link connected to the access point. This
allows the link test to check both the wireless and wired links.
Step 3 You can set the link test to run until it has attempted to send a specific number of packets or to run until
you stop it. Follow one of the steps below to determine how long the link test will run:
• Type the number of packets that the link test should attempt to send in the Number of Packets field.
(The Number of Packets parameter is ignored if the Continuous Link Test check box is selected.)
Range: 1 to 1000
Default: 1
• Select the Continuous Link Test check box to allow the link test to run continuously.
Default: Deselected
Step 4 Type the size of the data packet that is to be sent to the access point in the Packet Size field.
Range: 64 to 1514
Default: 64
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Diagnostic Tools for Mac OS 9
Step 5 Click the Start button to run the link test. While the test is running, statistics are displayed and updated
periodically.
Figure 7-4 shows the Link Test screen while it is running.
Figure 7-4 Link Test Screen (While Running)
Chapter 7 Performing Diagnostics
Table 7-1 interprets the statistics that are displayed on the Link Test screen while the link test is running.
Table 7-1 Link Test Statistics
Link Test Statistic Description
Packets Transmitted The number of packets of the specified size that were transmitted
successfully.
Packets Received The number of packets of the specified size that were received
successfully.
Packets Lost The numberof packets of the specifiedsize that were not received
successfully.
Status The operational mode of your client adapter.
Value: Error, Configured, Associated, Not Associated, or
Ad Hoc Mode
Name The name of the access point to which your client adapter is
associated. It is shown only if the access point was configured
with a name and you are in infrastructure mode.
MAC Address The MACaddress of the access point to which your client adapter
is associated. It is shown only if you are in infrastructure mode.
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