Cisco Aironet 340, 350, and CB20A Wireless LAN Client Adapters Installation and Configuration Guide for Windows, OL-1394-05
Chapter 7 - Performing Diagnostics
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Performing Diagnostics

Table Of Contents

Performing Diagnostics

Overview of ACU Diagnostic Tools

Setting Parameters that Affect ACU Diagnostic Tools

Viewing the Current Status of Your Client Adapter

Viewing Statistics for Your Client Adapter

Viewing the Link Status Meter

Running an RF Link Test


Performing Diagnostics


This chapter explains how to use ACU to perform user-level diagnostics.

The following topics are covered in this chapter:

Overview of ACU Diagnostic Tools

Setting Parameters that Affect ACU Diagnostic Tools

Viewing the Current Status of Your Client Adapter

Viewing Statistics for Your Client Adapter

Viewing the Link Status Meter

Running an RF Link Test

Overview of ACU Diagnostic Tools

In addition to enabling you to configure your client adapter for use in various types of networks, ACU provides tools that enable you to 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

Display statistics pertaining to your client adapter's transmission and reception of data

Display a graphical image of your client adapter's RF link

Run an RF link test to assess the performance of the RF link between your client adapter and its associated access point

Table 7-1 enables you to quickly locate instructions for using each of the diagnostic tools.

Table 7-1 Locating Diagnostic Instructions

Diagnostic Tool
Page Number

Status

page 4

Statistics

page 11

Link status meter

page 16

RF link test

page 17

Setting Parameters that Affect ACU Diagnostic Tools

Several parameters affect the operation of ACU diagnostic tools. Follow the steps below to set these parameters.


Step 1 Open ACU.

Step 2 Click the Preferences icon or select Preferences from the Options drop-down menu. The Aironet Client Utility Preferences screen appears (see Figure 7-1).

Figure 7-1 Aironet Client Utility Preferences Screen

Step 3 Table 7-2 lists and describes the parameters that affect the operation of ACU diagnostic tools. Follow the instructions in the table to change any parameters.

Table 7-2 Parameters Affecting ACU Diagnostic Tools 

Parameter
Description

Screen Update Timer (seconds between updates)

Specifies how often the Status and Statistics screens are updated. You can type a number in the edit box or use the slider to change this value.

Range: 1 to 60 seconds between updates (in 1-second increments)

Default: 1 second between updates

Signal Strength Display Units

Specifies the units used to display signal strength on the Status, Linktest, and Site Survey screens.

Default: Percent

Units

Description

Percent

Displays the signal strength as a percentage.

dBm

Displays the signal strength in decibels with respect to milliwatts.

Show History

Checking this check box causes the Link Status Meter 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 50 signals.

Default: Checked


Step 4 Click OK to save your changes.


Viewing the Current Status of Your Client Adapter

ACU enables you to view the current status of your client adapter as well as many of the settings that have been configured for the adapter.

To view your client adapter's status and settings, open ACU; then click the Status icon or select Status from the Commands drop-down menu. The Status screen appears. Figure 7-2 shows the Status screen with the signal strength values displayed as percentages, and Figure 7-3 shows the bottom of the same screen with the signal strength values displayed in decibels with respect to milliwatts (dBm).


Note The name of the current profile appears in parentheses at the top of the screen.


Figure 7-2 Status Screen (with Signal Strength as a Percentage)

Figure 7-3 Bottom of Status Screen (with Signal Strength in dBm)

Table 7-3 interprets each element of the Status screen.

Table 7-3 Client Adapter Status 

Status
Description

Device

A description of your client adapter.

Serial Number

The serial number of your client adapter.

Note The serial number appears only if the number has been programmed into your card.

Manufacturer

The manufacturer of your client adapter.

Firmware Version

The version of the firmware that is currently running on your client adapter.

Boot Block Version

The version of the boot block firmware that is currently in your client adapter. The boot block firmware contains identification information for the client adapter and functions to start up the radio and pass control to the main firmware, which (unlike the boot block) can be modified and upgraded by the user.

NDIS Driver Version

The version of the NDIS device driver that is currently installed on your computer.

Default Profile

The network configuration (or profile) shown in the Use Selected Profile drop-down box on the Profile Manager screen. This is the profile that you have selected as the active profile.

Note The current profile may be different than the default profile if you are using auto profile selection. The client adapter will not switch profiles as long as it remains associated to the access point or reassociates within 10 seconds (or within the time specified by the LEAP authentication timeout value if LEAP is enabled). Refer to Chapter 4, for information on creating and using profiles.

Current Profile

The network configuration (or profile) your client adapter is currently using.

Note The current profile may be different than the default profile if you are using auto profile selection. The client adapter does not switch profiles as long as it remains associated to the access point or reassociates within 10 seconds (or within the time specified by the LEAP authentication timeout value if LEAP is enabled). Refer to Chapter 4, for information on creating and using profiles.

Note If your current profile becomes disabled due to an invalid LEAP username and password, this field lists the profile as Disabled.

Using Short Radio Headers

Indicates whether your client adapter is actually using short radio headers.

Value: Yes or No

Note This setting appears only for 2.4-GHz client adapters.

Note Refer to the Use Short Radio Headers parameter in Table 5-3 for information on using short radio headers.

Using Message Integrity Check

Indicates whether your client adapter is using message integrity check (MIC) to protect packets sent to and received from the access point.

MIC prevents bit-flip attacks on encrypted packets. During a bit-flip attack, an intruder intercepts an encrypted message, alters it slightly, and retransmits it, and the receiver accepts the retransmitted message as legitimate.

Note MIC is supported automatically by the client adapter's driver, but it must be enabled on the access point.

Value: Yes or No

Server Based Authentication

Indicates the configuration of the access point to which your client adapter is associated.

Value: None, WEP Key In Use, Cell Is Secure, or LEAP Authenticated

Server Based Authentication
Description

None

The access point is configured for No Encryption.

WEP Key In Use

The access point is configured for Optional encryption.

Cell Is Secure

The access point is configured for Full Encryption.

Note If the client's current profile does not have Allow Association To Mixed Cells enabled, the client can associate only to access points that use full encryption.

LEAP Authenticated

The client is using LEAP and is authenticated to an access point that has WEP and Network-EAP enabled.

WEP (Wired Equivalent Privacy)

Your client adapter's current WEP status.

Value: Enabled, Not Enabled, or Need Firmware Upgrade

Note Refer to the "Setting Network Security Parameters" section for information on enabling WEP.

Authentication Type

Indicates whether the client adapter must share the same WEP keys as the access point in order to communicate or can communicate with the access point regardless of its WEP settings.

Value: Open or Shared Key

Note Refer to the "Setting Network Security Parameters" section for information on setting the authentication type.

Antenna Selection

The antenna mode that your client adapter is currently using.

Value: Diversity, Primary Only, Secondary Only
(Primary Only is the only option available for PCI client adapters)

Note This setting appears only for 2.4-GHz client adapters.

Note The Primary Only and Secondary Only values were formerly named Right Only and Left Only, respectively. Refer to the Antenna Mode (Receive) and Antenna Mode (Transmit) parameters in Table 5-4 and Table 5-5 for information on setting the antenna mode.

Channel Set

The regulatory domain for which your client adapter is currently configured, such as Americas. (For the Japan channel set, the Call ID is also displayed.) This value is not user selectable.

Note Refer to Appendix D, for a list of channel identifiers, channel center frequencies, and regulatory domains for each channel.

Client Name

The name your client adapter uses when it associates to an access point.

Note Refer to the Client Name parameter in Table 5-2 for information on setting the client name.

MAC Address

The MAC address assigned to your client adapter at the factory.

IP Address

The IP address of your client adapter.

Current Link Speed

The rate at which your client adapter is currently transmitting data packets.

Value: 1, 2, 5.5, or 11 Mbps (2.4-GHz client adapters);
6, 9, 12, 18, 24, 36, 48, or 54 Mbps (5-GHz client adapters)

Data Rate

The rate at which your client adapter has been configured to transmit or receive data packets.

Value: 1 Mbps, 2 Mbps, 5.5 Mbps, 11 Mbps, or Auto Rate Selection (2.4-GHz client adapters);
6 Mbps, 9 Mbps, 12 Mbps, 18 Mbps, 24 Mbps, 36 Mbps,
48 Mbps, 54 Mbps, or Auto Rate Selection (5-GHz client adapters)

Note Refer to the Data Rate parameter in Table 5-3 for information on setting the client adapter's data rate.

Current Power Level

The power level at which your client adapter is currently transmitting. The maximum level is dependent upon the radio installed in your client adapter and your country's regulatory agency.

Value: 1, 5, 15, or 30 mW (340 series client adapters);
1, 5, 20, 30, 50, or 100 mW (350 series client adapters);
5, 10, or 20 mW (5-GHz client adapters)

Note Refer to the Transmit Power parameter in Table 5-3 for information on setting the client adapter's power level.

Available Power Levels

The power levels at which your client adapter is capable of transmitting. The maximum level is dependent upon the radio installed in your client adapter and your country's regulatory agency.

Value: 1, 5, 15, or 30 mW (340 series client adapters);
1, 5, 15, 20, 30, 50, or 100 mW (350 series client adapters);
5, 10, or 20 mW (5-GHz client adapters)

Note Refer to the Transmit Power parameter in Table 5-3 for information on the client adapter's available power levels.

Channel (Frequency)

The frequency that your client adapter is currently using as the channel for communications.

Value: Dependent on client adapter radio and regulatory domain

Note Refer to the Channel parameter in Table 5-3 for information on selecting the frequency for your client adapter.

Status

The operational mode of your client adapter.

Value: Error, Not Associated, Associated, Authenticating, Authenticated, Authentication Failed, or Ad Hoc Mode

SSID

The name of the network to which your client adapter is currently associated.

Note Refer to the SSID1 parameter in Table 5-2 for information on the client adapter's SSID.

Network Type

The type of network in which your client adapter is being used.

Value: Infrastructure or Ad Hoc

Note Refer to the Network Type parameter in Table 5-2 for information on setting the network type.

Power Save Mode

The client adapter's current power consumption setting.

Value: CAM, Max PSP, or Fast PSP

Note Refer to the Power Save Mode parameter in Table 5-2 for information on setting the client adapter's power save mode.

Associated Access Point Name

The name of the access point to which your client adapter is associated. It is shown only if the client adapter is in infrastructure mode, the access point was configured with a name, and Aironet Extensions are enabled (on access points running Cisco IOS release 12.2(4)JA or greater).

Associated Access Point IP Address

The IP address of the access point to which your client adapter is associated. It is shown only if the client adapter is in infrastructure mode, the access point was configured with an IP address, and Aironet Extensions are enabled (on access points running Cisco IOS release 12.2(4)JA or greater).

Note If Aironet Extensions are disabled, the IP address of the associated access point is shown as 0.0.0.0.

Associated Access Point MAC Address

The MAC address of the access point to which your client adapter is associated. It is shown only if the client adapter is in infrastructure mode.

Note This field displays the MAC address of the access point's Ethernet port (for access points that do not run Cisco IOS) or the MAC address of the access point's radio (for access points that run Cisco IOS). The MAC address of the Ethernet port on access points that run Cisco IOS is printed on a label on the back of the device.

Beacon Period

Specifies the duration between beacon packets, which are used to help clients find each other in ad hoc mode.

Range: Approximately 20 to 999 milliseconds (ms)

Note The beacon period is shown only if your client adapter is in ad hoc mode.

Up Time (hh:mm:ss)

The amount of time (in hours:minutes:seconds) that the client adapter has been receiving power. If the adapter has been running for more than 24 hours, the time is displayed in days, hours:minutes:seconds.

Current Signal Strength

The signal strength for all received packets. The higher the value and the more green the bar graph is, the stronger the signal.

Range: 0 to 100% or -95 to -45 dBm

Current Signal Quality (2.4-GHz client adapters)

The signal quality for all received packets. The higher the value and the more green the bar graph is, the clearer the signal.

Range: 0 to 100%

Note This setting appears only for 2.4-GHz client adapters and only if you selected signal strength to be displayed as a percentage. See the Signal Strength Display Units parameter in Table 7-2 for information.

Current Noise Level (2.4-GHz client adapters)

The level of background radio frequency energy in the 2.4-GHz band. The lower the value and the more green the bar graph is, the less background noise present.

Range: -100 to -45 dBm

Note This setting appears only for 2.4-GHz client adapters and only if you selected signal strength to be displayed in dBm. See the Signal Strength Display Units parameter in Table 7-2 for information.

Current Beacons Received (5-GHz client adapters)

The percentage of beacon packets received versus those expected to be received. The higher the value and the more green the bar graph is, the clearer the signal.

Example: The access point sends out 10 beacons per second, so you
would expect the client adapter to receive 50 beacon packets
in 5 seconds. If it receives only 40 packets, the percentage of
beacons received would be 80%.

Range: 0 to 100%

Note This setting appears only for 5-GHz client adapters.

Overall Link Quality

The client adapter's ability to communicate with the access point, which is determined by the combined result of the adapter's signal strength and signal quality.

Value: Not Associated, Poor, Fair, Good, Excellent

Note This setting appears for 2.4-GHz client adapters (but only if you selected signal strength to be displayed as a percentage) and for 5-GHz client adapters. See the Signal Strength Display Units parameter in Table 7-2 for information.

Signal to Noise Ratio (2.4-GHz client adapters)

The difference between the signal strength and the current noise level. The higher the value, the better the client adapter's ability to communicate with the access point.

Range: 0 to 90 dB

Note This setting appears only for 2.4-GHz client adapters and only if you selected signal strength to be displayed in dBm. See the Signal Strength Display Units parameter in Table 7-2 for information.


Viewing Statistics for Your Client Adapter

ACU enables you to view statistics that indicate how data is being received and transmitted by your client adapter.

To view your client adapter's statistics, open ACU; then click the Statistics icon or select Statistics from the Commands drop-down menu. The Statistics screen appears (see Figure 7-4).


Note The name of the current profile appears in parentheses at the top of the screen.



Note The receive and transmit statistics are host statistics. That is, they show packets and errors received or sent by the Windows device. Link status tests from the access point or site survey tool are performed at the firmware level; therefore, they have no effect on the statistics shown in the Statistics screen.


Figure 7-4 Statistics Screen

The statistics are calculated as soon as your client adapter is started or the Reset button is selected and are continually updated at the rate specified by the Screen Update Timer. Instructions for changing the Screen Update Timer setting are provided in Table 7-2.

Table 7-4 describes each statistic that is displayed for your client adapter.

Table 7-4 Client Adapter Statistics 

Statistic
Description
Receive Statistics

Multicast Packets Received

The number of multicast packets that were received successfully.

Broadcast Packets Received

The number of broadcast packets that were received successfully.

Unicast Packets Received

The number of unicast packets that were received successfully.

Bytes Received

The number of bytes of data that were received successfully.

Beacons Received

The number of beacon packets that were received successfully.

Total Packets Received OK

The number of all packets that were received successfully.

Duplicate Packets Received

The number of duplicate packets that were received successfully.

Overrun Errors

The number of packets received when no receive buffers were available. These errors usually occur when the host does not read the received packets from the client adapter fast enough.

PLCP CRC Errors

The number of times the client adapter started to receive an 802.11 physical layer convergence protocol (PLCP) header but the rest of the packet was ignored due to a cyclic redundancy check (CRC) error in the header.

Note CRC errors can be attributed to packet collisions caused by a dense population of client adapters, overlapping access point coverage on a channel, high multipath conditions from bounced signals, or the presence of other 2.4-GHz signals from devices such as microwave ovens, wireless handset phones, etc.

PLCP Format Errors

The number of times an 802.11 PLCP header was received with a valid CRC but the rest of the packet was ignored due to an unknown value in the header.

PLCP Length Errors

The number of times an 802.11 PLCP header was received but the rest of the packet was ignored due to an illegal header length.

MAC CRC Errors

The number of packets that had a valid 802.11 PLCP header but contained a CRC error in the data portion of the packet.

Note CRC errors can be attributed to packet collisions caused by a dense population of client adapters, overlapping access point coverage on a channel, high multipath conditions from bounced signals, or the presence of other 2.4-GHz signals from devices such as microwave ovens, wireless handset phones, etc.

Partial Packets Received

The number of fragments that were discarded because the entire packet was not received successfully.

SSID Mismatches

The number of times the client adapter tried to associate to an access point but was unable to because the adapter's SSID was not the same as the access point's.

AP Mismatches

The number of times the client adapter tried to associate to an access point but was unable to because the access point was not the adapter's specified access point.

Note Refer to the Specified Access Point 1- 4 parameter in Table 5-4 for information on specifying access points.

Data Rate Mismatches

The number of times the client adapter tried to associate to an access point but was unable to because the adapter's data rate was not supported by the access point.

Note Refer to the Data Rate parameter in Table 5-3 for information on supported data rates.

Authentication Rejects

The number of times the client adapter tried to authenticate to an access point but was rejected.

Authentication Time-out

The number of times the client adapter tried to authenticate to an access point but was unable to because the access point did not respond fast enough (timed out).

Association Rejects

The number of times the client adapter tried to associate to an access point but was rejected.

Association Time-out

The number of times the client adapter tried to associate to an access point but was unable to because the access point did not respond fast enough (timed out).

Packets Aged

The number of packets received successfully but discarded by the client adapter because either all fragments were not received within 10 seconds or the host did not read the packet from the adapter within 10 seconds.

Packets MIC OK

The number of packets that were received successfully with a valid message integrity check (MIC).

Note This field is not displayed if MIC is not enabled on the access point.

Packets No MIC

The number of packets that were discarded due to no MIC being found.

Note This field is not displayed if MIC is not enabled on the access point.

Packets Incorrect MIC

The number of packets that were discarded due to an incorrect MIC value.

Note This field is not displayed if MIC is not enabled on the access point.

Packets No MIC Seed

The number of packets that were discarded due to no MIC seed being received.

Note This field is not displayed if MIC is not enabled on the access point.

Packets Wrong MIC Sequence

The number of packets that were discarded due to the MIC sequence number being wrong.

Note This field is not displayed if MIC is not enabled on the access point.

Up Time (hh:mm:ss)

The amount of time (in hours:minutes:seconds) since the Reset button was selected. If the client adapter has been running for more than 24 hours, the time is displayed in days, hours:minutes:seconds.

Total Up Time (hh:mm:ss)

The amount of time (in hours:minutes:seconds) that the client adapter has been receiving power. The total up time continues to increment even if the Reset button is selected. If the adapter has been running for more than 24 hours, the time is displayed in days, hours:minutes:seconds.

Transmit Statistics

Multicast Packets Transmitted

The number of multicast packets that were transmitted successfully.

Broadcast Packets Transmitted

The number of broadcast packets that were transmitted successfully.

Unicast Packets Transmitted

The number of unicast packets that were transmitted successfully.

Bytes Transmitted

The number of bytes of data that were transmitted successfully.

Beacons Transmitted

The number of beacon packets that were transmitted successfully (in ad hoc mode only).

Ack Packets Transmitted

The number of acknowledgment (Ack) packets that were transmitted in response to successfully received unicast packets.

RTS Packets Transmitted

The number of request-to-send (RTS) packets that were transmitted successfully.

CTS Packets Transmitted

The number of clear-to-send (CTS) packets that were transmitted in response to a successfully received RTS packet.

Single Collisions

The number of packets that had to be retransmitted once due to a collision.

Multiple Collisions

The number of packets that had to be retransmitted more than once due to additional collisions.

Packets No Deferral

The number of packets that were able to be transmitted immediately without being delayed due to energy detect or protocol deferral.

Packets Deferred Protocol

The number of packets that were delayed due to 802.11 protocol reasons (such as not enough time left to send the packet).

Packets Deferred Energy Detect

The number of packets that were delayed because RF energy was already detected. This condition is usually caused by another radio transmitting a packet or by some other RF source jamming the signal (such as a microwave oven).

Packets Retry Long

The number of normal data packets that were retransmitted.

Packets Retry Short

The number of request-to-send (RTS) packets that were retransmitted.

Packets Max Retries

The number of packets that failed to be transmitted successfully after exhausting the maximum number of retries.

Packets Ack Received

The number of transmitted packets that had their corresponding acknowledgment (Ack) packet received successfully.

Packets No Ack Received

The number of transmitted packets that did not have their corresponding Ack packet received successfully.

Packets CTS Received

The number of clear-to-send (CTS) packets that were received in response to an RTS packet.

Packets No CTS Received

The number of packets for which no CTS packet was received in response to an RTS packet.

Packets Aged

The number of packets that were discarded by the client adapter because they were not transmitted successfully within 5 seconds.


Viewing the Link Status Meter

ACU's link status meter can be used to assess the performance of your client adapter's RF link. If this tool is used 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 an access point.

To open the link status meter, open ACU; then click the Link Status Meter icon or select Link Status Meter from the Commands drop-down menu. The Link Status Meter screen appears (see Figure 7-5).


Note The name of the current profile appears in parentheses at the top of the screen.


Figure 7-5 Link Status Meter Screen

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 diagonal line (see Figure 7-5). Where the line falls on the graphical display determines whether the RF link between your client adapter and its associated access point is poor, fair, good, or excellent. The name, IP address, and MAC address of the access point that is associated to your client adapter are indicated at the bottom of the display.


Note The access point name and IP address are shown only if the client adapter is in infrastructure mode, the access point was configured with a name and an IP address, and Aironet Extensions are enabled (on access points running Cisco IOS release 12.2(4)JA or greater).



Note The access point MAC address is shown only if the client adapter is in infrastructure mode. This field displays the MAC address of the access point's Ethernet port (for access points that do not run Cisco IOS) or the MAC address of the access point's radio (for access points that run Cisco IOS). The MAC address of the Ethernet port on access points that run Cisco IOS is printed on a label on the back of the device.



Note ACU's Status screen also shows signal strength and signal quality. However on the Status screen, these data are represented by histograms.


If you want to see a recent history of the RF performance between your client adapter and its associated access point, check the Show History check box on the Aironet Client Utility Preferences screen. Black dots on the graphical display show the performance of the last 50 signals.

Running an RF Link Test

ACU's link test tool sends out pings to assess the performance of the RF link. The test is designed to be performed multiple times at various locations throughout your area and is run at the data rate set on ACU's RF Network Properties screen (see the Data Rate parameter in Table 5-3). The results of the link test can be used 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.

Because the link test operates above the RF level, it does more than test the RF link between two network devices. It also checks the status of wired sections of the network and verifies that TCP/IP and the proper drivers have been loaded.

The following prerequisites are required before you can run an RF link test:

The TCP/IP protocol must be installed on your system.


Note See the Help section of your Windows operating system for information on installing and setting up TCP/IP.


An IP address must be configured for the access point (or other computer in ad hoc mode).


Follow the steps below to run an RF link test.


Step 1 Open ACU; then click the Link Test icon or select Linktest from the Commands drop-down menu. The Linktest screen appears (see Figure 7-6).


Note The name of the current profile appears in parentheses at the top of the screen.


Figure 7-6 Linktest Screen

Step 2 In the IP Address of Access Point field, enter the IP address of the access point or other wireless device with which you want to test the RF link.

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:

Select the number of packets that the link test should attempt to send. You can type a number in the Number of Packets field or use the slider to select this value. (The Number of Packets parameter is ignored if the Continuous Linktest check box is checked.)

Range: 1 to 1000

Default: 4

Check the Continuous Linktest check box to allow the link test to run continuously.

Default: Unchecked

Step 4 Select the size of the data packet that is to be sent to the access point. You can type a number in the Packet Size field or use the slider to select this value.

Range: 64 to 2048

Default: 100


Note The Windows TCP/IP stack fragments (splits up) packets that are greater than 512 bytes. Therefore, the number of transmitted packets does not match the number of received packets (even if none are lost) if the packet size is greater than 512 bytes.


Step 5 Click the Start button to run the link test. While the test is running, statistics are displayed and updated periodically.

Figure 7-7 shows the Linktest screen with the signal strength values displayed as percentages, and Figure 7-8 shows the bottom of the same screen with the signal strength values displayed in dBm.

Figure 7-7 Linktest Screen (with Test Running and Signal Strength as a Percentage)

Figure 7-8 Bottom of Linktest Screen (with Test Running and Signal Strength in dBm)

Table 7-5 interprets the statistics that are displayed on the Linktest screen while the link test is running.

Table 7-5 Linktest Statistics 

Linktest Statistic
Description

Packets Received OK

The number of packets of the specified size that have been received successfully.

Packets Transmitted OK

The number of packets of the specified size that have been transmitted successfully.

Status

The operational mode of your client adapter.

Value: Error, Configured, Associated, Not Associated, or
Ad Hoc Mode

Current Link Speed

The rate at which your client adapter is currently transmitting data packets.

Value: 1, 2, 5.5, or 11 Mbps (2.4-GHz client adapters);
6, 9, 12, 18, 24, 36, 48, or 54 Mbps (5-GHz client
adapters)

Associated Access Point Name

The name of the access point to which your client adapter is associated. It is shown only if the client adapter is in infrastructure mode, the access point was configured with a name, and Aironet Extensions are enabled (on access points running Cisco IOS release 12.2(4)JA or greater).

Associated Access Point MAC Address

The MAC address of the access point to which your client adapter is associated. It is shown only if the client adapter is in infrastructure mode.

Note This field displays the MAC address of the access point's Ethernet port (for access points that do not run Cisco IOS) or the MAC address of the access point's radio (for access points that run Cisco IOS). The MAC address of the Ethernet port on access points that run Cisco IOS is printed on a label on the back of the device.

Current Signal Strength

The signal strength for all received packets. The higher the value and the more green the bar graph is, the stronger the signal.

Range: 0 to 100% or -95 to -45 dBm

Current Signal Quality
(2.4-GHz client adapters)

The signal quality for all received packets. The higher the value and the more green the bar graph is, the clearer the signal.

Range: 0 to 100%

Note This setting appears only for 2.4-GHz client adapters and only if you selected signal strength to be displayed as a percentage. See the Signal Strength Display Units parameter in Table 7-2 for information.

Current Noise Level
(2.4-GHz client adapters)

The level of background radio frequency energy in the 2.4-GHz band. The lower the value and the more green the bar graph is, the less background noise present.

Range: -100 to -45 dBm

Note This setting appears only for 2.4-GHz client adapters and only if you selected signal strength to be displayed in dBm. See the Signal Strength Display Units parameter in Table 7-2 for information.

Current Beacons Received (5-GHz client adapters)

The percentage of beacon packets received versus those expected to be received. The higher the value and the more green the bar graph is, the clearer the signal.

Example: The access point sends out 10 beacons per second, so
you would expect the client adapter to receive 50
beacon packets in 5 seconds. If it receives only 40
packets, the percentage of beacons received would be
80%.

Range: 0 to 100%

Note This setting appears only for 5-GHz client adapters.

Overall Link Quality

The client adapter's ability to communicate with the access point, which is determined by the combined result of the adapter's signal strength and signal quality.

Value: Not Associated, Poor, Fair, Good, Excellent

Note This setting appears for 2.4-GHz client adapters (but only if you selected signal strength to be displayed as a percentage) and for 5-GHz client adapters. See the Signal Strength Display Units parameter in Table 7-2 for information.

Signal to Noise Ratio
(2.4-GHz client adapters)

The difference between the signal strength and the current noise level. The higher the value, the better the client adapter's ability to communicate with the access point.

Range: 0 to 90 dB

Note This setting appears only for 2.4-GHz client adapters and only if you selected signal strength to be displayed in dBm. See the "Signal Strength Display Units" parameter in Table 7-2 for information.


Step 6 If you did not set the link test to run continuously, the test ends after the specified number of packets is sent, and the Stop button changes back to the Start button. To stop the link test at any time, click Stop, OK, or Cancel.