AirMagnet® Spectrum XT User Guide
© 2009-2011 Fluke Corporation. All rights reserved. AirMagnet® Spectrum XT User Guide. This User Guide is furnished under license and may be used or copied only in accordance with the terms specified in the license. The content of this document is for information only and should not be construed as a commitment on the part of AirMagnet, Inc.
Software License Agreement i Software License Agreement PLEASE READ THIS SOFTWARE LICENSE AGREEMENT (“LICENSE”) CAREFULLY. IF YOU DO NOT AGREE TO THE TERMS OF THIS LICENSE, DO NOT USE THE AIRMAGNET SOFTWARE AND RETURN THE UNUSED AIRMAGNET SOFTWARE WITHIN THIRTY (30) DAYS TO THE PLACE WHERE YOU OBTAINED IT FOR A REFUND. 1. GRANT OF LICENSE.
ii Software License Agreement 2. TITLE, COPYRIGHT AND TRADEMARK. Software is owned by Fluke Electronics Corporation and is protected by United States copyrights laws and international treaty provisions. Therefore you must treat the Software like any other copyrighted material. You own the media on which the AirMagnet Software is recorded but Fluke Network’s and/or Fluke Networks’ licensor(s) retain title to the AirMagnet Software.
Software License Agreement iii PLEASE NOTE: If Fluke Networks discovers or has reason to believe that you have breached your obligations under this License, including but not limited to your unauthorized use of the AirMagnet Software, Fluke Networks reserves the right in its sole discretion to (1) disable your access to any copies of AirMagnet Software in your possession or under your control and (2) seek monetary damages against you up to the maximum amount permitted by law.
iv Software License Agreement 7. LIMITATION OF LIABILITY. UNDER NO CIRCUMSTANCES, INCLUDING NEGLIGENCE, SHALL FLUKE NETWORKS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES ARISING OUT OF OR RELATING TO THIS LICENSE. SOME JURISDICTIONS DO NOT ALLOW THE LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES SO THIS LIMITATION MAY NOT APPLY TO YOU. In no event shall Fluke Networks’ total liability to you for all damages exceed the amounts paid by you hereunder. 8. GOVERNMENT END USERS.
Table of Contents v Table of Contents Software License Agreement .................................................................................................................................... i Chapter 1: Introduction ..............................................................................................................................................1 Product Overview.............................................................................................................................
vi Table of Contents System Requirements .......................................................................................................................................................6 Adapters .............................................................................................................................................................6 Laptop/Tablet PC ...................................................................................................................................
Table of Contents vii Chapter 4: Menus and Tools ...................................................................................................................................29 Chapter Summary...........................................................................................................................................................29 Selecting a Radio Band....................................................................................................................................
viii Table of Contents Custom Signature During File Playback .....................................................................................................60 Chapter 6: Analyzing Spectrum Data....................................................................................................................61 Chapter Summary...........................................................................................................................................................
Table of Contents ix Channel Signal/Noise Ratio........................................................................................................................................103 Channels by Retry/CRC ..............................................................................................................................................103 Chapter 8: Finding Devices ...............................................................................................................................
x Table of Contents Impact on 802.11b/g WLAN.......................................................................................................126 Recommended Courses of Action ..............................................................................................126 Wireless Cameras..........................................................................................................................................126 RF Spectrum Pattern......................................................
Table of Contents xi WiFi Devices ..................................................................................................................................................................142 802.11 a/g/n APs..........................................................................................................................................142 RF Spectrum Pattern.....................................................................................................................
xii AirMagnet Spectrum XT User Guide Table of Contents
Chapter 1: Introduction 1 Chapter 1: Introduction Product Overview AirMagnet Spectrum XT is a brand-new WiFi troubleshooting and optimization tool from AirMagnet, Inc. designed to provide WiFi network professionals with a clear and concise view into their wireless network environment. AirMagnet Spectrum XT’s power reaches far beyond its sleek and intuitive design, because it includes the option to complement spectrum analysis with WiFi packets and traffic analysis, using an optional second WiFi card.
2 Chapter 1: Introduction Channel Power Graph The Channel Power graph shows the current and maximum (aggregated) channel energy. The graph can display either Envelope Power or Integrated Power. The former refers to the highest power reading and the latter shows the total summation of power readings over a specific bandwidth. Channel Duty Cycle Graph The Channel Duty Cycle graph shows the percentage of the time that the average power in the channel is greater than 20 dBm above the noise floor.
Chapter 1: Introduction 3 AP Signal Strength Graph The AP Signal Strength graph identifies and displays up to three APs with the strongest signal strengths on each available channel in the selected radio band. Top 10 APs by Speed Graph The Top 10 APs by Speed graph displays up to 10 APs with the fastest transmission speeds as well as the data rate or rates used by each of the top APs. Each bar represents an AP.
4 Chapter 1: Introduction Channels by Retry/CRC The Channels by Retry/CRC graph allows the user to quickly assess which channels are experiencing high levels of Retry or CRC packets. Auto Pattern Detection and Custom Device Classification Auto Pattern Detection and Custom Device Classification enables users to identify, classify, and analyze interferers beyond those devices included in the software package.
Chapter 1: Introduction 5 Saving Recorded Capture Data This feature allows the user to save to a .amt file the live data they have recorded. To save recorded data, the user must stop recording data or let the application automatically stop recording once the Max Live Capture Streaming File Size [MB] is reached. The data saved in a. amt file can then be played back in the application for analysis. Replaying Saved Capture Data This feature allows the user to replay recorded data that has been saved in a .
6 Chapter 1: Introduction • .JPG • .GIF System Requirements Minimum System requirements for installing and operating AirMagnet Spectrum XT vary, depending on the hardware platforms being used: Note: 64-bit Operating System supported on Windows 7 for certain wireless adapters. Please refer to supported adapter list for more details.
Chapter 1: Introduction • 7 Optional Windows-compatible Bluetooth adapter (required for enhanced Bluetooth interferer information) Apple® MacBook® Pro • MAC OS X Leopard™, MAC OS X Snow Leopard™ [running Windows XP™ PRO (SP3) or Microsoft® Windows 7 Professional/Enterprise/Ultimate using Boot Camp®; Parallels Desktop® or VMWare Fusion® running Windows XP PRO (SP3) or Microsoft® Windows 7 Professional/Enterprise/Ultimate • Intel 2.2 GHz Core 2 Duo or higher • Microsoft.NET Framework 2.
8 Chapter 1: Introduction Supported Wireless Network Adapters An AirMagnet-supported wireless network adapter is required in order to capture and display WiFi data in AirMagnet Spectrum XT. For a complete, up-to-date listing of AirMagnet-supported wireless adapters, visit http://www.airmagnet.com/support/ supported_adapters/.
Chapter 1: Introduction 9 Figure 1-1: AirMagnet Spectrum XT on the OptiView INA Usability The sections below detail some of the features specific to the OptiView machine designed to enhance the user experience and make AirMagnet Spectrum XT easier to use. MyTTouch Soft Keyboard Any window in which the user is expected to enter text should automatically open the MyTTouch Soft Keyboard, which allows the user to provide text input.
10 Chapter 1: Introduction Right Mouse-Click Emulation In order to access the right-click menu used by many AirMagnet Spectrum XT screens, tap and hold until the menu appears (note that it is important that the user not move the cursor after the initial tap until the menu appears). Alternatively, users can also tap the mouse icon in the System Tray (shown in Figure 1-3) to specify that the next tap will emulate a right-click.
Chapter 2: Getting Started 11 Chapter 2: Getting Started Chapter Summary This chapter discusses the procedures for installing AirMagnet Spectrum XT. It covers the following topics: • Preparing for software installation • Installing AirMagnet Spectrum XT from a CD • Registering Your AirMagnet Spectrum XT • Seeking Technical support Preparing for Software Installation This section contains instructions on the installation of the AirMagnet Spectrum XT software.
12 Chapter 2: Getting Started If the installation fails to start automatically, browse to the CD-ROM drive on your computer and double-click the autorun.exe file inside the folder. Figure 2-1: AirMagnet Spectrum XT Autorun The Autorun menu allows the user to install the components of AirMagnet Spectrum XT as well as access product documentation. The following sections will go through the basic process of installing the components of AirMagnet Spectrum XT.
Chapter 2: Getting Started 13 To install AirMagnet Spectrum XT: 1) From the Autorun menu, click Spectrum XT Installation. The installation wizard appears. 2) Click Next to view the AirMagnet Inc. Software License Agreement. 3) Check the I accept the terms of the license agreement radio button and click Next. 4) Specify an installation path and click Next. 5) Click Install to begin the installation. 6) After the procedure has completed, click Finish to exit the install wizard.
14 Chapter 2: Getting Started Figure 2-3: Entering your serial number and serial key 3) Select Download a license file from www.airmagnet.com and click Next. The following screen appears. See Figure 2-4. Figure 2-4: Downloading the license file online 4) Enter your software’s serial number and serial key.
Chapter 2: Getting Started 15 5) If you have AirMagnet Gold Support for this product, check the box and enter the support contract serial number and serial key. 6) Click Next. The Adapter and USB Serial Number fields are greyed out by default, but they will be automatically populated once you have entered the correct serial number and serial key.
16 Chapter 2: Getting Started Installing the License File Locally The following instructions apply if you already have a valid AirMagnet Spectrum XT license file stored locally, either on your computer or your network. To install your software license file locally: 1) Repeat Steps 1 through 2 in the previous section until the License Download screen appears. 2) Select Browse for a license file from local machine and click Next. You will be prompted to enter the location of the license file.
Chapter 2: Getting Started 17 To register your AirMagnet Spectrum XT: 1) Follow the instructions on the AirMagnet Product Registration Web page to register your AirMagnet Spectrum XT. See the illustration in Figure 2-6. Figure 2-6: AirMagnet Product Registration page If you prefer to register your AirMagnet Spectrum XT at a later time, you can open the same Product Registration Web page using the Web address http://www.airmagnet.
18 Chapter 2: Getting Started • Free software updates/upgrades (new features and product enhancements) when available • Hardware support, repair and replacement for AirMagnet products* * Must meet terms and conditions as defined in the hardware warranty • Free access to “AirMagnet Certified Professional” web-based training for certain AirMagnet products • MAC Address Reset assistance Contact Customer Support • Navigate to http://www.airmagnet.
Chapter 3: AirMagnet Spectrum XT User Interface 19 Chapter 3: AirMagnet Spectrum XT User Interface Chapter Summary This chapter discusses the major components of AirMagnet Spectrum XT’s user interface. It describes what they are and how they can be used in analyzing spectrum and/or WiFi data that are captured on your network.
20 Chapter 3: AirMagnet Spectrum XT User Interface 1 3 2 4 Figure 3-1: AirMagnet Spectrum XT Major UI Components Table 3-1 provides the names of the UI components highlighted in Figure 3-1. Each of these components is discussed in detail in the rest of this chapter.
Chapter 3: AirMagnet Spectrum XT User Interface 21 Toolbar The toolbar contains all the tools for operating AirMagnet Spectrum XT. While some of the tools have their names spelt out, others come with a tool tip which will reveal the name of a tool when you place the cursor over it. Many of them contain submenus in the form of a dropdown list menu, as indicated by the down arrow next to it. Figure 3-2 highlights all the tools on the toolbar. Detailed descriptions of these tools are presented in Table 3-2.
22 Chapter 3: AirMagnet Spectrum XT User Interface Table 3-2: AirMagnet Spectrum XT Menus/Tools ID Tool Name Description 2 Band Contains the following options (which determine the 802.11 radio spectrum the application focuses on): • 2.4 GHz - covers the radio frequency range from 2.402 GHz to 2.842 GHz, which is used by Channels 1 through 14. • 5 GHz Lower - covers the radio frequency range from 5.17 GHz to 5.33 GHz, which is used by Channels 44, 48, 52, 56, 60, and 64.
Chapter 3: AirMagnet Spectrum XT User Interface 23 Table 3-2: AirMagnet Spectrum XT Menus/Tools ID Tool Name Description 9 Resume/ Play In live capture mode, this button is named Resume which allows you to resume live capture after it is paused. In playback mode, it is named Play which allows you to play back the data or file after the playback is stopped. 10 Pause Pauses live data capture.
24 Chapter 3: AirMagnet Spectrum XT User Interface Table 3-2: AirMagnet Spectrum XT Menus/Tools ID Tool Name Description 15 Help Contains the following submenus: • Content - opens the Content tab of the online Help. • Search - opens the Search tab of the online Help. • About - open the About AirMagnet Spectrum XT dialog box which contains the following three tabs: • AirMagnet Spectrum XT - shows basic information about AirMagnet Spectrum XT.
Chapter 3: AirMagnet Spectrum XT User Interface 25 Table 3-3 briefly describes the data displayed in this part of the screen. Table 3-3: Channel Summary Data Description Column Description Channel All available channels in the selected radio band. Current The average of current FFT readings in dBm on each channel. Avg The average historical FFT readings in dBm on each channel. Max The maximum FFT reading in dBm on each channel. Duty Cycle The percentage of time the RF energy (both 802.
26 Chapter 3: AirMagnet Spectrum XT User Interface Channel Devices The bottom part of the Spectrum-WiFi Summary is Channel Devices, which lists the number of APs, stations, and/or VoFi phones that have been detected on channel in the selected 802.11 radio band. Similar to the AP List above, this part of the screen is devoted to the display of WiFi data only. You must have an AirMagnet-supported external wireless network adapter in order for AirMagnet Spectrum XT to capture and display such data.
Chapter 3: AirMagnet Spectrum XT User Interface 27 Figure 3-7: WiFi graph options An AirMagnet-supported external wireless network adapter is required to view all options in WiFi Graphs. Otherwise, you will find some options showing limited static data while others simply being disabled. In the upper-right corner of each graph is a (Help) button. Clicking this button will bring up the AirMagnet Spectrum XT’s online help page relevant to the graph.
28 AirMagnet Spectrum XT User Guide Chapter 3: AirMagnet Spectrum XT User Interface
Chapter 4: Menus and Tools 29 Chapter 4: Menus and Tools Chapter Summary This chapter discusses the menus and tools in AirMagnet Spectrum XT and ways to use them to configure and manage the various parameters in AirMagnet Spectrum XT to better server your needs.
30 Chapter 4: Menus and Tools The radio frequency ranges and channels covered by each radio band as mentioned in Table 4-1 apply to US and North America only. They may vary in other countries or regions of the world. Switching from one radio band to another will cause the application to discard old data captured on the ‘old” radio band before it starts scanning the “new” band. For this reason, changing bands is like resetting the application.
Chapter 4: Menus and Tools 31 Figure 4-2: Add View showing right-click options Managing Live Data Capture By default, AirMagnet Spectrum XT is able to capture live spectrum and WiFi data and display them on the screen in real time. To enable the user to conduct focus analysis of any specific segment of data flow that has been captured, the application offers a number of tools on the toolbar that the user can use to suspend, resume, stop, and restart live capture as needed.
32 Chapter 4: Menus and Tools To replay captured data that has just been displayed on the screen: 1) Click (Switch to Instant Playback) on the toolbar. The application will start to play back the capture data that has just been displayed on the screen. See Figure 4-3. Figure 4-3: Instant playback of capture data The application can instantly play back data captured in the last two minutes at most. The replay stops when the slider reaches the end.
Chapter 4: Menus and Tools 33 Opening a Capture Data File Captured data are saved to a file using the .amt file extension. You can replay those saved capture data by opening the file containing the data. To open a capture file: 1) Click 2) Locate the .amt file on your PC and click Open. 3) Use the buttons (Start, Pause, and Stop) to play the file back and forth, if you wish to. 4) To switch back to Live Capture mode, click (Open Capture File). (Switch to Live Capture).
34 Chapter 4: Menus and Tools To set or change the display of WiFi or spectrum data: 1) From the toolbar, click Settings>Configure...The default Configure dialog box appears. Figure 4-4: Configuring General settings 2) Make the selections as described in Table 4-3. 3) Click Apply and then OK when done. Table 4-2: Configuring AirMagnet Spectrum XT’s General Settings Parameter Description WiFi Devices These parameters apply to WiFi devices only.
Chapter 4: Menus and Tools 35 Table 4-2: Configuring AirMagnet Spectrum XT’s General Settings Parameter Description Spectrum This parameter applies to spectrum data only. Auto reset spectrum data If selected, AirMagnet Spectrum XT will automatically reset spectrum data at the interval specified by the user. See below. Spectrum data reset period (This option becomes available only when Auto reset spectrum data is selected. See above.) Specify the interval for the application to reset spectrum data.
36 Chapter 4: Menus and Tools Selecting Another WiFi Driver By default, each time you start AirMagnet Spectrum XT, the application will always look for and use the WiFi driver that was used in the previous session. If the user has only one WiFi driver installed on the PC, this should not be a problem. However, if you have more than one WiFi driver installed on the PC and you prefer to use a different WiFi driver than the one you used before, this may be somewhat inconvenient.
Chapter 4: Menus and Tools 37 Figure 4-6: Band Settings Tab Modifying Display Options The Display Options tab allows the user to alter various aspects of the application’s overall appearance. See Figure 4-7. Figure 4-7: Display Options Refer to Table 4-3 for information regarding each of the options provided.
38 Chapter 4: Menus and Tools Table 4-3: Display Options Option Description Alert Settings When enabled, this option will highlight the Duty Cycle column in the Channel Summary field when it exceeds the specified threshold. Channels on which the Duty Cycle meets this criteria will be highlighted in red (channels with normal levels are highlighted in green). Channel Shadow Settings In WiFi deployment channels 1,6 and 11 in the 2.4 GHz spectrum are used.
Chapter 4: Menus and Tools 39 Figure 4-8: Record Options Files saved in .csv format cannot be played back using AirMagnet Spectrum XT. To record .csv files: 1) From the Record Options tab, click the csv radio button. 2) Select either Spectrum data or Wifi data to be used. 3) Specify the folder in which the files should be saved, either by entering the path manually or by clicking the Browse… button. 4) Enter a prefix for the files, if desired.
40 Chapter 4: Menus and Tools Virtual AP Grouping AirMagnet Spectrum XT’s Virtual AP Grouping feature allows users to set up specific names for single devices hat utilize multiple SSIDs under different BSSIDs. These groups help users identify instances where separate BSSIDs show up and appear to be several different devices, when they actually belong to a single device. See Figure 4-9. Spectrum comes with several built-in “automatic” AP Group rules.
Chapter 4: Menus and Tools 41 Auto Group Rules You may configure different fields in the Auto AP Group Rules by clicking on the New button. See Figure 4-10. Figure 4-10: Editing an Auto Group Manual Group Rules You may manually add groups by clicking the New button for Manual Group and add a Group name and AP Name. See Figure 4-11.
42 Chapter 4: Menus and Tools With AirMagnet Spectrum XT 2.0.2, users have the ability to remotely log into the user interface and monitor ambient traffic patterns using a separate machine. In order to connect to the XT remote interface, users must install the AirMagnet Spectrum XT Viewer-Only license (provided with the purchase of a valid AirMagnet Spectrum XT license) on the second machine.
Chapter 4: Menus and Tools 43 Figure 4-13: SNMP Filters tab • Download AirMagnetSpectrumInterferer.mib from the download page of the AirMagnet Spectrum XT in your SNMP management station. • Compile the MIB file and ebale your SNMP management station to receive traps. Currently there is a trap that is generated by the AirMagnet Spectrum XT for each detected device based on the Filter conditions set in the Filter tab. • The IANA assigned Private Enterprise Number for AirMagnet Inc. is 16603.
44 Chapter 4: Menus and Tools The trap will have the following details: Device Type Device Identifier Device Description First Seen Time Last Seen Time Channel Max Power at the Channel Average Power at the Channel Center Frequency of the Channel Remote Spectrum Analysis The Remote Spectrum Analysis feature can be used to give access to and control of the AirMagnet Spectrum XT application to a user that is offsite.
Chapter 4: Menus and Tools 45 Figure 4-15: Remote Access Authentication screen Using Easy View Options The Easy View tool allows the user to filter data to be displayed on the screen so that they can focus more on data of interest. Figure 4-16 shows the default options in the Easy View drop-down list menu. Figure 4-16: Easy View The upper part contains the application’s built-in easy view options; the lower part provides tools for creating, deleting, and saving custom view options.
46 Chapter 4: Menus and Tools Table 4-5: AirMagnet Spectrum XT Default Easy View Options View Description Spectrum View (default) shows the Real-Time FFT graph, along with the Spectrum Density and AP Signal Strength graphs. Density View shows the Spectrum Density graph, along with Channels by Speed graph. RF Usage View shows the Real-Time FFT, Spectrogram and Spectrum Density graphs. RF Channel View shows the Real-Time FFT, Channel Duty Cycle, and Channel Power graphs.
Chapter 4: Menus and Tools 47 Figure 4-17: Creating a new Easy View 3) Type a name for the new view and click OK. You can create more custom view options by following the same steps outlined above. All custom options you create will be automatically appended to the bottom of the Easy View list menu. Deleting a Custom View Option Unlike those built-in Easy View options, custom easy view options can be deleted if you want to.
48 Chapter 4: Menus and Tools Automatically Saving Current View To let AirMagnet Spectrum XT automatically save the current view: 1) From the toolbar, click Settings>Configure. 2) Under the General tab, check Auto Save Custom View. 3) Click Apply and then OK. Once the Auto Save Custom View option is enabled, AirMagnet Spectrum XT will automatically save the custom view you have created before ending the current session and open in the same view at the next start.
Chapter 4: Menus and Tools 49 Figure 4-19: Copying a graph image 3) Open an application that supports copy and paste, such as MS Word. 4) Use the Paste command to paste the image to the document. 5) Save the document. Saving Screen Data as Image Files AirMagnet Spectrum XT allows the user to save any graph shown in the graph window as an image file in any of the following four image formats: • .PNG • .BMP • .JPG • .
50 Chapter 4: Menus and Tools Dwell Time (FFT Max Data Sampling Duration) This feature can effectively reduce noise in order to produce a better distinguishable FFT pattern. For example, adjusting the bar to 50% will reduce sampling by half, thereby smoothing out spikes in the FFT graph that may be caused by interference noise. Top adjust the FFT Max Data Sampling Duration: : 1) From the toolbar, click Configure> General Tab. 2) Press and drag the bar between Min and Max.
Chapter 5: Auto Pattern Detection and Custom Device Classification 51 Chapter 5: Auto Pattern Detection and Custom Device Classification Chapter Summary This chapter discusses Auto Pattern Detection and Custom Device Classification, both features enabling users to identify, classify, and analyze interferers beyond those devices included in the software package. • Auto Pattern Detection: The system identifies and lists persistent RF patterns that do not match its database of interferers.
52 Chapter 5: Auto Pattern Detection and Custom Device Classification Note: If a pattern is no longer detected after one minute, it will be removed from the Detected Patterns list and the pattern count will be reduced by one to reflect that the pattern is no longer detected.
Chapter 5: Auto Pattern Detection and Custom Device Classification 53 To create a custom signature of a pattern: 1) From the Settings drop-down menu, select Show Auto Detected Patterns. 2) Click the desired pattern from the pattern list on the left side of the window. 3) Replace New Signature with a custom name for the signature. 4) You may also assign the signature to a group using Group Name.
54 Chapter 5: Auto Pattern Detection and Custom Device Classification What the user can tune: The Auto Detect feature processes both the “current” and the “max” FFT data. As such there are two parameters the user may tune in order to affect the algorithm: “Noise Floor for max Reading” and “Noise Floor for Current Reading”. See Figure 5-3.
Chapter 5: Auto Pattern Detection and Custom Device Classification 55 Figure 5-4: Device Detected To create a custom device classification signature: 1) First, wait until you see a distinct pattern for the device on the Max or Current Line of the FFT graph. By default, the visibility of Current Line is not enabled on the Real Time FFT chart. The user can enable it from the chart configuration window.
56 Chapter 5: Auto Pattern Detection and Custom Device Classification Figure 5-5: Range Defined Custom Classification Window 4) Narrow down the pattern window from the entire spectrum to just the frequencies that are relevant to the device. To do this, click the left edge of the desired range and drag to the right edge of the range. 5) Replace New Signature with a custom name for the signature. 6) You may also assign the signature to a group using Group Name.
Chapter 5: Auto Pattern Detection and Custom Device Classification 57 value between 30% and 100%. For environments with high amounts of spectrum data, most loosely constrained patterns can yield better detection rates, and can also lead to potential false detections. More tightly constrained patterns, meaning a higher threshold, means that there will be fewer false detections, with a chance that there will also be fewer actual detections that fall just out of range of the constraints.
58 Chapter 5: Auto Pattern Detection and Custom Device Classification Figure 5-7: Device List and non-WiFi Devices Panel Export/Import Custom Signatures AirMagnet Spectrum XT supports the ability to share the defined signatures between users. The user can export the interested signatures to a file which can be shared with other users. The user who received a signature file should import the signature into their system to make use of it.
Chapter 5: Auto Pattern Detection and Custom Device Classification 59 Figure 5-8: Signature Export The exported signatures from the file can be imported into the system by clicking the Import button and selecting the appropriate file. The available device signatures list all the signatures available on the file. The user can selectively import one or more signatures into the system. The imported signatures will be merged into the signature file persistant on the system.
60 Chapter 5: Auto Pattern Detection and Custom Device Classification Custom Signature During File Playback The custom devices classified during recording phase will not be saved into the trace file. Custom signatures will be reevaluated during file playback for possible classification of the custom devices. AirMagnet Spectrum XT does allows the user to create new custom signature in playback mode. Signatures defined during playback will be evaluated against the captures data for the device detection.
Chapter 6: Analyzing Spectrum Data 61 Chapter 6: Analyzing Spectrum Data Chapter Summary This chapter discusses in detail the various spectrum graphs that AirMagnet Spectrum XT offers. It describes the data contained in each of these graphs and the ways to configure those graphs to customize the presentation and analysis of spectrum data captured on your network.
62 Chapter 6: Analyzing Spectrum Data • Channel Duty Cycle vs Time • Interference Power vs Time All these graphs are listed in the Spectrum Graphs list menu, which is available in all individual graphs. To access the Spectrum Graphs list menu: 1) From graph window, click the title of a graph. 2) From the drop-down menu, select Spectrum Graphs. See Figure 6-1.
Chapter 6: Analyzing Spectrum Data 63 As seen from Table 6-1, the Real Time FFT graph may display four types of spectrum data that are color-coded. The number of data types displayed depends on the configuration settings. Table 6-1: Real Time FFT Graph Parameters Color Spectrum Data Description Yellow Max-hold The highest power readings that have been recorded since the session began. Red Max The maximum power in the RF Spectrum of a single channel sweep. Each FFT consists of 256 samples in 6.
64 Chapter 6: Analyzing Spectrum Data Technically the power range in the Real Time FFT graph can be set as low as -140 dBm (Minimum Power) and/or as high as 0 dBm (Peak Power). When a narrower power range is used, e.g., -120 dBm ~ -30 dBm, the user may notice some discrepancy between what is shown in the Real Time FFT graph and what is displayed in the tool tip when the actual power readings fall beyond either or both the Minimum Power and/or Peak Power limit.
Chapter 6: Analyzing Spectrum Data 65 To configure Real-Time FFT graph parameters: 1) From the upper-right corner of the Real Time FFT graph, click (Chart Configuration). The Real-Time FFT Configuration dialog box. See Figure 6-5. Figure 6-5: Configuring Real Time FFT graph 2) Make the entries and/or selections as described in the Table 6-2. 3) Click Apply and then OK.
66 Chapter 6: Analyzing Spectrum Data Table 6-2: Setting Real Time FFT Graph Parameters Parameter Description Show Current Allows the user to show or hide the current power readings in the FFT graph. Click in the field and use the down arrow to select either of the following: • Yes - displays the current power readings. • No - hides the current power readings. Show Duty Cycle The duty cycle data will overlay the FFT graph as semi-transparent bars • Yes - displays the duty cycle overlay.
Chapter 6: Analyzing Spectrum Data 67 Table 6-2: Setting Real Time FFT Graph Parameters Parameter Description Spectrum Type Allows the user to decide where (which part of the FFT graph) the marker or markers should fall. Click in the field and use the down arrow to select one of the following: • Current - places the marker or markers on the Current power readings.
68 Chapter 6: Analyzing Spectrum Data Figure 6-6: Spectrum Density graph Viewing AP Signal Strengths Across Frequency Range You can also display the signal strengths of APs selected from the AP List by SSID/Channel on the left-hand side of the screen. The signal strengths of the selected APs appear in the form of curves across the corresponding frequency range used by the APs. Notice that the selected APs and their signal strength readings are color-coded with matching colors for easy identification.
Chapter 6: Analyzing Spectrum Data 69 To configure Spectrum Density graph parameters: 1) From the upper-right corner of the Spectrum Density graph, click (Chart Configuration). The Spectrum Density Configuration dialog box. See Figure 6-8. Figure 6-8: Configuring Spectrum Density graph 2) Make the desired selections and/or entries as described in Table 6-3. 3) Click Apply and then OK.
70 Chapter 6: Analyzing Spectrum Data Table 6-3: Setting Spectrum Density Graph Parameters Parameter Description Color Scale Mode Allows the user to set or change the color scale modes of the Spectrum Density graph. As indicated by the legend in the upper-right corner of the plot, the color scale mode range from blue (Minimum Percentage) to red (Maximum Percentage).
Chapter 6: Analyzing Spectrum Data 71 The text message at the bottom of the Spectrum Density Configuration dialog box changes with the parameter you select. It provides a brief description of the parameter being selected. Spectrogram Graph The Spectrogram graph provides another way to present the same data as shown in the RealTime FFT graph. It allows you to visualize the changes in the spectrum over a period of time and to easily identify any shift in frequency use and the duration of such shifts.
72 Chapter 6: Analyzing Spectrum Data To configure Spectrogram graph parameters: 1) From the upper-right corner of the Spectrogram graph, click (Chart Configuration). The Spectrogram Configuration dialog box appears. See Figure 6-10. Figure 6-10: Configuring Spectrogram graph 2) Make the desired selections and/or entries as described in Table 6-4. 3) Click Apply and then OK.
Chapter 6: Analyzing Spectrum Data 73 Table 6-4: Configuring Spectrogram Graph Parameters Parameter Description Maximum Allows the used to set or change the maximum power value in dBm in the Spectrogram graph. By default, the Maximum Power value is -20, but you can change it to any value less than 0 dBm. The Maximum value appears on the right end of the color scale. Any value that exceeds the set maximum will appear in red. Highlight the existing Maximum value and override with a new value.
74 Chapter 6: Analyzing Spectrum Data Channel Power Types The Channel Power can be defined either as Envelope or Integrated. Envelope power is defined as the maximum, or peak, energy level in a channel’s frequency range. Integrated power is similar, and is defined as the average power of all frequency power levels in a channel’s frequency range. In the bar chart, the Max bar corresponds to the Max data line on the FFT chart, while the Avg bar corresponds to the Average data line on the FFT graph.
Chapter 6: Analyzing Spectrum Data 75 To configure Channel Power graph parameters: 1) From the upper-right corner of the Channel Power graph, click (Chart Configuration). The Channel Power Configuration dialog box. See Figure 6-12. Figure 6-12: Configuring Channel Power graph 2) Make the desired selections and/or entries as described in Table 6-5. 3) Click Apply and then OK.
76 Chapter 6: Analyzing Spectrum Data Table 6-5: Configuring Channel Power Graph Parameters Parameter Description Channel Power Type Select one of the following: • Envelope - The highest energy reading that has been reached at a particular frequency with a frequency range. See the description at the beginning of this section. • Integrated - The total summation of energy reading of an entire frequency range. See the description at the beginning of this section.
Chapter 6: Analyzing Spectrum Data 77 Figure 6-13: Channel Duty Cycle graph Configuring Channel Duty Cycle Graph Parameters You can set or change the parameters in the Channel Duty Cycle graph using the Chart Configuration button. To configure Channel Duty Cycle graph parameters: 1) From the upper-right corner of the Channel Duty Cycle graph, click (Chart Configuration). The Channel Duty Cycle Configuration dialog box. See Figure 6-14.
78 Chapter 6: Analyzing Spectrum Data Table 6-6: Channel Duty Cycle Graph Parameters Parameter Description Chart Type Toggles between column and stacked column displays. When viewing by stacked column, the data for WiFi and non-WiFi data will be displayed in a single column, with WiFi data stacked on top of the non-WiFi information. Show Non-WiFi Enables or disables display of non-wifi data. Show WiFi Enables or disables display of wifi data.
Chapter 6: Analyzing Spectrum Data • Zigbee Devices • Non-Bluetooth Wireless Mouse • Motion Detector • Radar 79 Figure 6-15 shows the information contained in the Non-WiFi Devices table. Figure 6-15: Non-WiFi Devices The Non-WiFi Devices table shows the following information about each non-WiFi device that are listed: • Name (Device Type) - The device category a device belongs to (refer to the bullet list above). • Peak Power dBm - The highest energy reading in dBm ever recorded of device.
80 Chapter 6: Analyzing Spectrum Data Event Spectrogram The Event Spectrogram provides a visual presentation of real-time information about events (device detections) that the application has made in the network. Each detection is an event which is represented by a color band. The color of the band indicates the signal strength of the device being detected (refer to the signal scale on top of the graph).
Chapter 6: Analyzing Spectrum Data 81 To set or change parameters in the Event Spectrogram plot: 1) Click the Chart Configuration button in the upper-right corner. The Event Spectrogram Configuration dialog box opens. See Figure 6-17. Figure 6-17: Configuring Event Spectrogram 2) 3) Make the desired changes to the following parameters: • Maximum - The maximum energy level to show in the Event Spectrogram, which is on the red end of the color legend.
82 Chapter 6: Analyzing Spectrum Data Figure 6-18: Interference Power Chart As noted in the color legend above the main portion of the chart, the yellow points on the graph represent the current signal strength of the strongest AP detected on each channel; hovering over the point provides the device’s name and MAC address. The point’s location on the chart indicates the level of interference that it is experiencing; as the interference level climbs, the device’s performance can suffer as a result.
Chapter 6: Analyzing Spectrum Data 83 To set or change parameters in the Interference Power plot: 1) Click the Chart Configuration button in the upper-right corner. The Interference Power Configuration dialog box opens. See Figure 6-19. Figure 6-19: Configuring Interference Power 2) 3) Make the desired changes to the following parameters: • Minimum Power—The minimum power level that will be displayed on the graph. • Peak Power—The maximum power level that will be displayed on the graph.
84 Chapter 6: Analyzing Spectrum Data Figure 6-20: Channel Duty Cycle vs Time graph As shown above, the graph will display up to three channels at a time in color-coded lines. The channels can be modified via the chart configuration, as discussed below. Configuring Channel Duty Cycle vs Time You can set or change the parameters in the Channel Duty Cycle vs Time graph using the Chart Configuration button.
Chapter 6: Analyzing Spectrum Data 3) 85 Click Apply and then OK. Table 6-7: Channel Duty Cycle vs Time Graph Parameters Parameter Description Trend Options Use these fields to specify the channels that should be displayed in the graph. Users can select up to three channels at any single time. Show First/ Second/Third Trace These fields activate or deactivate the trace options specified in the first portion of the configuration. Select ‘Yes’ to activate (e.g., display) each trace as needed.
86 Chapter 6: Analyzing Spectrum Data Configuring the Interference Power vs Time Graph As mentioned above, the configuration menu for the Interference Power vs Time graph allows the user to alternate between displaying interference data by channel and by device type. Refer to Table 6-8 for specific options that can be configured in the graph, as shown below.
Chapter 6: Analyzing Spectrum Data 87 BlueSweep Integration BlueSweep software is designed to identify nearby devices with Bluetooth wireless technology and alert users to potential Bluetooth security risks. It identifies and tracks devices up to 300 feet away and lets users know what their own Bluetooth devices are doing. BlueSweep runs on laptop computers that support Windows XP.
88 Chapter 6: Analyzing Spectrum Data Figure 6-25: BlueSweep Active Setting Figure 6-26: BlueSweep Inactive Setting AirMagnet Spectrum XT User Guide
Chapter 7: Analyzing WiFi Data 89 Chapter 7: Analyzing WiFi Data Chapter Summary This chapter discusses in detail the various WiFi graphs that AirMagnet Spectrum XT offers. It describes the data contained in each of these graphs and the ways to use them to analyze WiFi traffic on your network.
90 Chapter 7: Analyzing WiFi Data To access the WiFi Graphs list menu: 1) From graph window, click the title of a graph. 2) From the drop-down menu, select WiFi Graphs. See Figure 7-1. Figure 7-1: WiFi Graph options As shown in Figure 7-1, the WiFi Graphs list menu contains all WiFi graphs AirMagnet Spectrum XT can generates. You can display any of them simply by clicking the option of your choice.
Chapter 7: Analyzing WiFi Data 91 Figure 7-2: WiFi Devices The WiFi Device graph provides comprehensive data about each WiFi device that AirMagnet Spectrum XT has detected in the network. Table 7-1 briefly describes the data contained in the WiFi Devices graph.
92 Chapter 7: Analyzing WiFi Data Table 7-1: WiFi Device Data Data Description Last Frame Time Last Frame Time - The time the last frame involving a device was detected. AP Name The name of the AP itself or of the AP that provides service to a station or phone. Since the WiFi Devices graph contains a great deal of data that require a lot of screen space, you may need to custom AirMagnet Spectrum XT’s user interface in a way to make it easy for you to view WiFi device data.
Chapter 7: Analyzing WiFi Data 93 Table 7-2: Color Data Description Aqua 1st Max The highest AP signal strength detected. Blue 2nd Max The second highest AP signal strength. Green 3rd Max The third highest AP signal strength. If you place the cursor over a portion of a channel bar marked by any of the colors, a tip screen will appear showing the information about the AP. See Figure 7-4.
94 Chapter 7: Analyzing WiFi Data Channel Occupancy Graph The Channel Occupancy graph shows all the available channels for the selected radio band and which APs are occupying which channels. See Figure 7-5. Figure 7-5: Channel Occupancy graph As seen from the illustration above, each column in the Channel Occupancy graph represents a channel in the selected radio band, and each row represents an AP that has been detected.
Chapter 7: Analyzing WiFi Data 95 Modulated interference refer to interference that occurs within a device's modulated spectrum (i.e., within the device’s operating channel width), whereas unmodulated interference refers to interference caused by the “bleed over” of signals beyond the modulated portion of the transmission. Like the WiFi Devices graph, the Channel Occupancy graph requires more screen space to display its content.
96 Chapter 7: Analyzing WiFi Data Table 7-4: Color Scheme for Transmission Rates Color Transmission Rate (in Mbps) Blue .11n (for 802.11n devices) Orange 36~54 Green 12~24 Yellow 11 Aqua 2~9 Red 1 If you place the cursor over a particular channel, a tip screen will appear providing some brief statistics of the amount data transmitted at the various transmission rates used on that channel.
Chapter 7: Analyzing WiFi Data 97 Table 7-5: Color Scheme for 802.11 Media Types Color Media Type Blue 802.11n Orange 802.11g Green 802.11b Aqua 802.11a If you place the cursor over a channel, a tip screen will pop up showing the volume of data transmitted using each type of media. See Figure 7-8.
98 Chapter 7: Analyzing WiFi Data As shown in Figure 7-9, three types of addresses can be used for network traffic. The addresses are coded in distinctive colors, which are described in Table 7-6. Table 7-6: Color Scheme for Channels by Address Graph Color Address Description Aqua Broadcast The process of sending the same data to all stations on the network. Yellow Multicast The process of sending a single message to multiple destinations simultaneously.
Chapter 7: Analyzing WiFi Data 99 Channel Utilization The Channel Utilization graph shows the percentage of bandwidth being used on each channel and the breakdown of the utilization by transmission rate. The X-axis shows all available channels for the selected radio band as well as the transmission rates being used on each channel; the Y-axis shows the overall percentage of bandwidth being used on each channel. See Figure 7-11.
100 Chapter 7: Analyzing WiFi Data Figure 7-12: Viewing channel bandwidth breakdown by data rate Top 10 APs by Speed The Top 10 APs by Speed graph shows the 10 APs that have transmitted the most amount of data (in kilobytes) as well as the breakdown of the transmissions by data rate on each AP. The X-axis shows the names of the top 10 APs and the transmission rates being used by the APs; the Y-axis shows the volume of data in kilobytes being recorded. See Figure 7-13.
Chapter 7: Analyzing WiFi Data 101 Table 7-8: Color Scheme for Top 10 APs by Speed Graph Color Transmission Rate (in Kilobytes) Blue .11nM (for all 802.11n transmissions) Orange 36~54 Green 12~24 Yellow 11 Aqua 2~9 Red 1 If you place the cursor over a bar, a tip screen will pop up showing the breakdown of the volume of transmission by transmission rate by that AP. See Figure 7-14.
102 Chapter 7: Analyzing WiFi Data Figure 7-15: Top 10 Active APs’ Retry/CRC As shown in Figure 7-15, the CRC and Retry packets are color-coded, with red for CRC and green for Retry. The APs are identified by name, IP address, or whatever identification is used on the network. If you place the cursor on an AP, a tip screen will pop up showing some basic information about the AP and the percentages of Retry and CRC packets transmitted by the AP. See Figure 7-16.
Chapter 7: Analyzing WiFi Data 103 Channel Signal/Noise Ratio The Channel Signal/Noise Ratio graph shows the ratio of signal to noise present on each displayed channel. The X-axis shows the list of selected channels while the Y-axis displays the ratio in terms of dB. See Figure 7-17. Figure 7-17: Channel SNR Graph Channels by Retry/CRC The Channels by Retry/CRC graph shows the percentage of traffic present on each channel composed of Retry and Cyclic Redundancy Check (CRC) packets.
104 AirMagnet Spectrum XT User Guide Chapter 7: Analyzing WiFi Data
Chapter 8: Finding Devices 105 Chapter 8: Finding Devices Chapter Summary This chapter discusses how to use the Find Device tool to physically locate various spectrum devices that the application has detected on your network.
106 Chapter 8: Finding Devices Figure 8-1: Find Device Screen The following sections discuss in detail the various components of the Find Device screen. Event Log In the upper-left pane of the Find Device screen is the Event Log. It shows the following information about the device being selected: • Detected Time - The data and time of each instance when the device was detected. • Channel - The channel on which the device was detected.
Chapter 8: Finding Devices 107 Figure 8-2: Detailed information about a selected device The information displayed will vary, depending on the type of device detected (802.11 or non802.11). As shown in Figure 8-2, the Device Details pane shows the following information for standard 802.11 devices: • Device Name - The device category the selected device belongs to (i.e., Bluetooth Device, Digital Cordless Phone, etc.) • Mac Address - The MAC address of the device.
108 Chapter 8: Finding Devices • First Seen Time - The first time the device was detected. • Last Seen Time - The most recent time the device was detected. Device Pattern In the lower-left corner of the screen is the Device Pattern pane which shows the RF spectrum pattern of the device being selected. The is chart is also available on the Spectrum-WiFi Summary screen. See Figure 8-3.
Chapter 8: Finding Devices 109 Figure 8-4: Close-up view of Find Device Tool The Find Device tool has the following components: • Device Drop-Down List Menu – Allows the user to select an entry among all detected devices in the selected radio band. • Find/Stop Button – allows the user to start or stop a device-locating operation. • Sound Check Box – If checked, the application will start ticking while searching for a device. The sound becomes louder as you get closer to the device.
110 Chapter 8: Finding Devices You can use the scroll bar or arrows on the right to view the full description of the device being selected. Physically Locating a Device on the Network Theoretically, you can locate any device that the application has detected on the network, using the following instructions. To physically locate a device on the network: 1) Make sure that the device is selected in the Device Drop-Down List Menu. 2) Click Find. 3) Check the Sound check box, if you like.
Chapter 8: Finding Devices 111 5) Start the Find Tool. 6) Slowly turn around until you locate the direction in which the device’s signal strength is the strongest. 7) As directly as possible, move in the direction of the strongest signal. Move slowly, covering about one meter every three to five seconds. 8) When the signal has climbed to its highest point, or appears to be roughly the same no matter what direction the antenna is facing, observe the area to locate your interfering device.
112 AirMagnet Spectrum XT User Guide Chapter 8: Finding Devices
Chapter 9: Radar Detection Tool 113 Chapter 9: Radar Detection Tool Chapter Summary This chapter discusses the Radar Detection Tool that can be used to detect radar in the wireless LAN environment. It covers the following topics: • Introduction • Radar Tool UI Components • Using the Radar Detection Tool Introduction The 5-GHz band is an Unlicensed National Information Infrastructure (UNII) band, which is divided into several segments, each being designated for a specific use. The UNII-2 (5.
114 Chapter 9: Radar Detection Tool Note: Most radar signals come in short bursts, followed by a dead time. Detection by SpectrumXT would require that the bursts arrive while the SpectrumXT is on the correct channel. The chances of this happening in the short-term may be very low. The best way to detect the radar is to dwell on each channel for a period of time that includes several sweeps of the radar. This could range from 10ths of seconds to several minutes. Impact on 802.11 WLAN Since the 802.
Chapter 9: Radar Detection Tool 115 Radar Detection Tool UI Components This section describes the options in the Radar Detection Tool user interface. Figure 9-1: Radar Detection Tool User Interface Table 9-1: Radar Detection Tool UI Components Option Description Settings bar This is the heading for the Settings panel. You may collapse the Setting panel by clicking the push pin icon located to the right of the Settings bar.
116 Chapter 9: Radar Detection Tool Table 9-1: Radar Detection Tool UI Components Option Description Scan When the box next to a channel listing is checked, this channel will be scanned during a scanning session. Period (min) This column provides a drop-down menu for each channel that can be used to manually set the time the associated channel will be scanned during the session. Clear All Click this button to un-check all the channels.
Chapter 9: Radar Detection Tool 117 Using the Radar Detection Tool To use the Radar Detection Tool: 1) From the File menu select Radar Detection Tool. This will open the Radar Detection Tool window. 2) In the Settings panel, select the desired Radar Class Type from the drop-down menu. 3) Set the desired channels to scan by adjusting the checked options in the Scan column.
118 AirMagnet Spectrum XT User Guide Chapter 9: Radar Detection Tool
Chapter 10: Device Detection 119 Chapter 10: Device Detection Chapter Summary AirMagnet Spectrum XT can detect and identify various 802.11 or non-802.11 devices that are operating in your WiFi network by looking at the unique patterns of energy emitted from those devices. This chapter discusses the major categories of devices that AirMagnet Spectrum XT is able to detect. It talks about the modulation method, typical RF spectrum pattern, impact on WiFi networks of these devices.
120 Chapter 10: Device Detection similar devices (i.e., two microwaves from different vendors). Consequently, the device’s pattern may not always be an exact match for the example provided in the application. Non-WiFi (Spectrum) Devices The section discusses the various non-WiFi (spectrum) devices that AirMagnet Spectrum XT is able to detect in a wireless network environment.
Chapter 10: Device Detection 121 Impact on 802.11b/g WLAN Because the 2.4-GHz radio band is unlicensed (free to all), there are numerous Bluetoothenabled devices by different manufacturers available on the market. The following is a short list of such devices: • Laptops • PDAs • Headsets • Headphones • Mice • Keyboards • Dongles • Adapters • Speakers, etc. These Bluetooth devices are becoming increasingly popular in homes and businesses where 802.
122 Chapter 10: Device Detection 802.11b/g WLAN in close proximity. As a result, no matter which channel your WLAN use or switch to (Remember that there are only 3 non-overlapping channels in the 2.4-GHz radio band, i.e., channels 1, 6, and 11), it is hard for 802.11b/g APs to escape the RF interference caused by 2.4-GHz FHSS digital cordless phones. Such sources of interference can cause significant disruption in WLAN service and performance degradation.
Chapter 10: Device Detection 123 Figure 10-4: RF spectrum pattern of a 5.8-GHz FHSS digital cordless phone Impact on 802.11 WLAN Because the 2.4-GHz and 5-GHz radio bands are unlicensed (free to all), there are numerous 2.4-/5-GHz digital cordless phones by different manufacturers available on the market. They are widely used in homes and businesses where 802.11b/g or 802.11a WLANs are deployed. They have been recognized as a major source of RF interference for 802.11b/g or 802.11a WLANs.
124 Chapter 10: Device Detection Analog Cordless Phones Analog cordless phones are another source of interference to 802.11b/g or 802.11a wireless LANs (WLANs). Unlike digital cordless phones, analog cordless phones use narrowband transmission which occupies only a narrow bandwidth of the RF spectrum. Because of this, they can cause severe interference to an 802.
Chapter 10: Device Detection 125 Recommended Courses of Action Once interfering analog cordless phones are successfully located, you can take the following actions to minimize or eliminate their RF interference to your 802.11 WLAN: • If you have an 802.11b/g WLAN, avoid or stop using analog cordless phones on the same channel as your 802.11a/b/g APs. Instead try to set them on other nonoverlapping channels. • If you are using an 802.11b/g WLAN, try to use 5.
126 Chapter 10: Device Detection Figure 10-6: RF spectrum pattern of a microwave oven Impact on 802.11b/g WLAN Because microwave ovens are widely used in homes and businesses where WLANs are deployed, radio signals leaking out of an operating microwave oven have long been identified as a source of RF interference to 802.11b/g WLANs in these settings. They can significantly slow down basic Internet applications such as Web file download and surfing.
Chapter 10: Device Detection 127 which varies from 200 to 700 feet (line of sight), depending on the physical conditions of the site. Typically, multiple cameras are needed in order to provide full, overlapping coverage of one site. To make matters worse, wireless security cameras installed in homes and businesses are left on all the time. And so is the RF interference they cause to the 802.11 WLAN close to them. RF Spectrum Pattern Wireless cameras come in all shapes and sizes.
128 Chapter 10: Device Detection Baby Monitors Wireless baby monitors (digital or analog) use radio frequencies to transmit their signals. These same radio frequencies are also used by wireless networks installed in the home environment. As a result, RF interference will occur when the two competing systems are operating in the same radio frequencies. RF Spectrum Pattern Most wireless baby monitors on the market today use the 2.4-GHz frequency, a bandwidth also used by the 802.
Chapter 10: Device Detection 129 • If you do not want to upgrade your wireless network, then try to get a wireless baby monitor that uses any radio frequency other than 2.4 GHz, such as 900 MHz. • Since a baby monitor does not severely disrupt a wireless network unless the two are installed close together, try to place the wireless baby monitor and the wireless router as far apart as possible. RF and Narrowband Jammer RF Jammer is designed to block WiFi/WLAN/Bluetooth networks which work on the 2.
130 Chapter 10: Device Detection Figure 10-10: Interference Source - Narrowband Jammer Impact on WiFi on WiFi Networks WiFi Jammers are designed to protect important working area and avoid leakage of sensitive data by blocking WiFi networks. Since it works in the 2.4 GHz frequency band and channels, this type of device can be a good “defensive” tools against data leakage over wireless network, but can also be a “double-edged sword”. Anyone could use it to disrupt the operation of a wireless network.
Chapter 10: Device Detection 131 Digital Video Monitors A digital video monitor is typically made up of three components: a video camera, a transmitter to send the signal, and a receiver to receive the signal. The system works in such a way that the wireless camera transmits video from the built-in transmitter to the receiver, which is connected to a display device (monitor) or a recording device. Most digital video monitors operate on the 2.4-GHz frequency – an unlicensed radio band also used by 802.
132 Chapter 10: Device Detection • If you are using an 802.11b/g WLAN, avoid using 2.4-GHz digital video monitors. Instead, use 5.8-GHz video monitors that operate in the less crowded 5-GHz radio band. Or upgrade your WLAN to the 802.11n standard which offers better interference avoidance. • If you are using an 802.11a WLAN, avoid using 5.8-GHz digital video monitors.
Chapter 10: Device Detection 133 Figure 10-12: Interference Source - Zigbee Impact on 802.11b/g WLAN Given the fact that a 2.4-GHz Zigbee network operates on a fixed 3 MHz of bandwidth in the 2.4-GHz band, the chance of collision between a Zigbee device and an 802.11b or g device depends on the channels on which they operate. If the channels overlap, the chance are high. Otherwise, the chances are very low.
134 Chapter 10: Device Detection Motion Detector Motion detectors are devices that use a variety of methods to determine if a body of a significant size is coving through an area, usually as part of a security or energy management system. While most models use infrared detection system, some newer models incorporate a microwave detection system. In some models, this microwave detection system transmits on a narrow band of frequency in the 2.4GHz band.
Chapter 10: Device Detection 135 within the channel width of a WLAN AP, and only if it is significantly close enough to the WLAN network to have an impact. • If the motion detector is in an area of high pedestrian traffic, is on a frequency within the channel width of the WLAN AP, and if it is significantly close enough to interfere with the WLAN, this device type can have a signaificant impact on a WLAN, behaving almost as a Narrow-band Jammer would.
136 Chapter 10: Device Detection • Conduct regular WLAN site RF surveys to determine the proper location and use of RF Signal Generators, if they are necessary. • If it is necessary to use the RF Signal Generator, only use it on channels that do not overlap with the channels used by your WLAN.
Chapter 10: Device Detection 137 technologies that allow their devices to operate in a way that minimizes the impact on WLAN networks. With the ability to find a frequency with the least amount of WLAN traffic in the 2.4 GHz spectrum, non-bluetooth wireless mice minimize their impact on the WLAN network. See Figure 10-15 below. Figure 10-15: Non-Bluetooth Wireless Mouse Fill RF Spectrum Pattern To date, the only devices detected for this device type are made by Logitech.
138 Chapter 10: Device Detection Logitech’s proprietary wireless protocol is used together with a high-performance RF transceiver. This is a highly integrated, single-chip transceiver that operated in the 2.4 GHz ISM band and is really suited for the most demanding applications. In addition to the technical features described above, this technology also provides the lowest-power RF solution on the market today, translating into significantly longer battery life. Table 10-1: Feature Logitech advanced 2.
Chapter 10: Device Detection 139 Wireless Game Controllers Wireless game controllers are handheld devices for gaming consoles without wires. Using wireless technology, wireless game controllers allow players to sit virtually anywhere (up to 30 feet away from the game console) in the room, making game play less restrictive. For better coverage, most wireless game controllers operate on the 2.4-GHz frequency–an unlicensed radio band also used by 802.
140 Chapter 10: Device Detection Impact on 802.11b/g WLAN Because wireless game controllers operate in the same radio frequency as the 802.11b/g WLAN, radio signals from these devices have long been identified as a source of RF interference to 802.11b/g WLANs in homes and businesses where they are used. They can significantly slow down Internet applications such as Web file download and surfing.
Chapter 10: Device Detection • Lucent • Netwave Technologies • Symbol Technologies • Proxim Wireless 141 The figure below shows the RF spectrum pattern of a 2.4GHz 802.11FHSS device. Figure 10-17: Frequency-hopping Spread Spectrum device Impact on 802.11 WLAN 802.11FHSS devices can have a significant to severe impact on your WLAN. Because these devices hop across the entire band in a semi-random pattern, no 802.11 channel is considered safe from these devices. The actual impact of the 802.
142 Chapter 10: Device Detection • If optimal WLAN performance is not an issue, you may continue use your 2.4-/5GHz cordless phones along with 802.11b/g or 802.11a WLANs but try to maximize the distance between APs and cordless phone bases to minimize their RF interference between each other. • Consider upgrading your WLAN to 802.11n standard, which not only provides better RF interference avoidance mechanisms but also offer greater throughput.
Chapter 10: Device Detection 143 RF Spectrum Pattern 802.11a APs operate in the “regulated” 5-GHz frequency band, meaning that they use radio frequencies that are not used by other commercial wireless products. Unlike 802.11 b/g WLANs which have only three non-overlapping channels, 802.11a WLANs have eight nonoverlapping channels to choose from. Figure 10-18 shows the RF spectrum pattern of an 802.11g/n AP in the 2.402-2.482 GHz frequency range. Figure 10-18: RF spectrum pattern of an 802.
144 Chapter 10: Device Detection 802.11g APs are backward-compatible with 802.11b APs but offer greater data rates. However, since they operate in the same radio frequencies as their 802.11b counterparts, they are susceptible to RF interference caused by all wireless devices operating in the 2.4-GHz frequency band. See 802.11b APs. 802.11n APs, by design, can co-exist with 802.11a APs in the 5-GHz band and 802.11g APs in the 2.4-GHz band since they all use OFDM. The presence of 802.
Chapter 10: Device Detection 145 As the number of these devices increases, the 2.4-GHz IMS band is becoming more and more congested. As a result, network performance degradation has become a major issue facing network administrators managing 802.11b/g WLANs. It has long been recognized that the main culprit for WLAN performance degradation is RF interference caused by these competing devices in the 2.4-GHz band.
146 Chapter 10: Device Detection Recommended Courses of Action Since 802.11b/g WLANs are operating in the crowded 2.4-GHz IMS band with so many competing devices (including 802.11b/g devices themselves), the following actions are recommended in order to minimize or eliminate RF interference to 802.11b/g WLANs: • Prior to installing an 802.11b WLAN, conduct a thorough RF survey of the WLAN site to know all 2.4-GHz devices operating in the WiFi environment and the channels they are using. • Install 802.
Appendix A: Abbreviations & Acronyms 147 Appendix A:Abbreviations & Acronyms This section lists the abbreviations and acronyms that appear on AirMagnet Spectrum XT user interface and/or in this User Guide. The full forms of these terms are also given. The definitions of these terms are provided in Appendix B, “Glossary”. List of Abbreviations and Acronyms Abbreviation or Acronym Full Form a 802.11a AP Access Point Auto Automatic Avg Average b 802.
148 Appendix A: Abbreviations & Acronyms List of Abbreviations and Acronyms Abbreviation or Acronym Full Form WPA Wireless Protected Access AirMagnet Spectrum XT User Guide
Appendix B: Glossary 149 Appendix B:Glossary 2.4 GHz Band An option in the Band drop-down list menu, if selected, allows the application to display data captured over the 2.402 GHz ~ 2.482 GHz radio frequency range which covers Channels 1 through 13. 802.1x A standard designed to enhance 802.11 WLAN security. It provides an authentication framework for WLANs so that users can be authenticated by a central authority.
150 Appendix B: Glossary A newer standard of WLAN technology designed to significantly improve network throughput over previous standards (i.e., 802.11a, b, and g) by adding multiple-input multiple-output (MIMO) and channel-bonding/40-MHz operation to the physical (PHY) layer, and frame aggregation to the MAC layer. The 802.11n standard promises data rates up to 600 Mbps. AP (Access Point) A hardware device that links or bridges wireless stations to a wired network.
Appendix B: Glossary 151 Band Refers to the radio band which is a section of the spectrum of the 802.11 radio communication frequencies in which 802.11 radio channels are allocated. AirMagnet Spectrum XT provides four basic band segments (i.e., 2.4 GHz, 5 GHz Lower, 5 GHz Middle, and 5 GHz Upper) whose ranges are based upon a wireless network adapter’s capability and determined by the regional settings burned into the adapter’s EEPROM.
152 Appendix B: Glossary Crash Any critical failure in a computer, network device, or software application that runs on such devices. When a crash occurs, a computer may freeze or hang indefinitely. A crash could occur without warning. The user may have to power down and then restart the computer or network device in order to recover from a crash. CRC (Cyclical Redundancy Check) An error-checking technique used to ensure the accuracy of data transmitted over the network.
Appendix B: Glossary 153 A non-profit engineering organization in the United States that develops, reviews, and promotes standards within the electronics and computer industries. Interference In wireless networking, the disturbance that results when radio signals from different APs collide in the airwave. IP (Internet Protocol) address A 32-bit unique string of numerical characters used to identify a networked computer, printer, or any other device.
154 Appendix B: Glossary A parameter in the configuration of Real-Time FFT, Spectrum Density, and Channel Power graphs. By default, it is -120 dBm, but the user can set it to any value as long as it less than the Peak Power but equal to or greater than -140 dBm. See Peak Power. Mixed A option in the Band drop-down list menu, if selected, allows the application to display data captured across all 802.11 radio spectrums and channels. See also 2.4 GHz, 5 GHz Lower, 5 GHz Middle, and 5 GHz Upper.
Appendix B: Glossary 155 Signal In wireless networking, any electrical pulse or frequency that carries meaningful data. See RSSI. Spectrum Density Graph A graph that shows the “popularity” of a particular frequency/power reading over time in the radio spectrum. Spectrum Type (Current, Average, Maximum) Refers to the type of spectrum data presented in the Real-Time FFT graph. AirMagnet Spectrum XT can show three types of spectrum data: • Current —The up-to-the-minute power readings being recorded.
156 Appendix B: Glossary A parameter used in the configuration of the Real-Time FFT, Spectrum Density, and Spectrogram graphs. It is the value of radio frequency at the upper end of the spectrum band in these graphs. See Start Frequency. Unicast The process of sending duplicates of the same message to multiple destinations on the network.
Appendix B: Glossary 157 WPA-Enterprise See WPA. WPA2 Short for Wi-Fi Protected Access 2, which is a follow-on security method to WPA for the WLAN. It provides stronger data security and network access control, assuring Wi-Fi users that only authorized users can access their WLANs. Based on the IEEE 802.11i standard, WPA2 meets the stringent US government-grade security by implementing the National Institute of Standards and Technology (NIST) FIPS 140-2 compliant AES encryption algorithm and 802.
158 AirMagnet Laptop Analyzer User Guide Appendix B: Glossary
Index 159 Index Numerics AirMedic CD 11 AirMedic menus and tools 29 AirMedic software CD 11 Alert Settings 38 Analog Cordless Phones 119 AP Name 92 AP signal curves 68 AP Signal Strength 3, 92 Auto 70 AutoHide 92, 95 average power 75 Channel Power Type 76 channel power types 74 channel scan indicator 27 Channel Summary 24 Channel Usage 26 Channel Utilization 99 Channel Utilization graph 3 channels 30 Channels by Address 97 Channels by Media 96 Channels by Speed 95 Chart Configuration button 27 Color Sca
160 Index Envelope 76 ETSI 115 Event Log 106 Event Spectrogram 2 Export (radar) 116 external wireless network adapter 27, 89 F Fast Fourier Transformation 62 FFT Channel Duty Cycle Overlay 64 FFT Graph Channel Duty Cycle 64 Fid Device 105 Find Device 4 Find Device tool 108 First Frame Time 91 fluorescent ligh 24 Frequency 38 N noise level 91 Non-WiFi Devices 2 non-WiFi devices 24 P G general WiFi and spectrum parameters graph window 26 graphs 26 H help button 33 pausing and resuming live capture p
Index save current view 47 save recorded data 5 Scan Time 116 security 91 serial key 11, 14 serial number 11, 14 Settings (radar) 115 Show Area Fill 65 signal strength 91 Signal Strength Gauge 109 Single maker 66 Software Installation 11 software installation 11 software license file 13 Spectrogram 71 Spectrogram graph 1 spectrum analysis 1 Spectrum Density 67 Spectrum Density graph 1 spectrum graphs 1, 61 Spectrum Type 67 Spectrum-WiFi Summary 24 SSID 91 Start Channel 76, 78 start frequency 67, 70, 73 Star
162 AirMagnet Spectrum XT User Guide Index
