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Network Testing and Emulation Solutions

LANforge WiFi Attenuation vs PDU Size Test

Goal: Compare WiFi performance for 'download' traffic (AP to Client) as Payload Size and RF Attenuation levels change using a WiFi access point, a LANforge Attenuator and a LANforge Virtual Station. Traffic is generated by a RFC-2544 script on a Layer-3 UDP connection.

This demo consists of one WiFi access point and one CT523 LANforge WiFIRE machine connected to the LANforge Attenuator with coax SMA cables. (This is not over the air testing).
  1. Create Layer-3 Cross Connect
    1. Go to the Layer 3 tab screenshot
      1. Click Create
    2. Create a cross connect with these settings: screenshot
      1. Make sure Endpoint A is eth2 or the wired port to the AP
      2. Make sure Endpoint B is wlan0 or the station associated with the AP
      3. Min PDU Size for both should be AUTO
      4. NOTE: These rate and PDU size settings will be manipulated by the script we setup later.
    3. Verify that the connection is operational before adding a script.
  2. Configure Scripting for Cross Connect
    1. On the Layer-3 tab, click Modify
    2. In the Level 2 box, click Endpoint A Script button screenshot
    3. The Cross Connect Script window displays with Script Type: NONE screenshot
    4. Select Script Type: RFC-2544 and default values appear: screenshot
      1. Select Show Attenuation. This displays attenuation levels in the report.
      2. Run Duration: 30 sec. This is how long each iteration will run.
      3. Pause Duration: 5 sec. We give it some time to transition.
    5. Setup Pass/Fail Criteria and Iteration Steps for the script. For each Attenuation Level, the script will step through each PDU size at the desired rate. If there were multiple rates then for each Attenuation Level, the script would step through each PDU size for each rate. screenshot
      1. Max Drop Percent 20%
      2. Max Jitter 200ms
      3. Max RT Latency 1000ms
      4. Rates A: 900Mbps. This sets the client download target rate.
      5. Pld A: 64,512,1024,1472
      6. Attenuator Resource: 1.1.35. You can find your attenuator resources in the Attenuator tab.
      7. Attenuation: 0..+50..955. This is shorthand for: Begin at zero dB attenuation, increase in 5.0dB steps, until 955 dB of attenuation. Individual dB steps could also be specified.
      8. Click OK
    6. On the Create/Modify Cross Connect window, click OK
  3. Save Data to be able to view past results. screenshot
    1. Go to Reporting Menu and select Reporting Manager
    2. Select the GUI Data Collection tab
    3. Choose a directory and select Save
  4. Run the Cross Connect and Generate a Report
    1. On the Layer-3 tab, click Start, and the Script Report window will appear. screenshot
    2. View the Dynamic Report
      1. While the script is running, you can view the real-time results of the running script.
      2. Right-Click on wlan0 and select Dynamic Report
      3. Setup the Dynamic Report to view the data you are interested in.
      4. wlan0: RX Signal level shown on Axis-B and RX bps shown on Axis-A screenshot
      5. To view Dynamic Report data after the test completes:
      6. Set the Reporting Manager, Generate Report to the directory containing saved data.
      7. Adjust the time scale and Load the data in the Dynamic Report window.
    3. View the graphical results of the script when it completes.
      1. In the Script Report window, click on Graphical Display and a window with the graphical report will display
      2. Scroll to the top of the window to view the graphs. Examples are shown below.
      3. Attenuation v. RX signal, endpoint A screenshot
      4. 3D graph of Peer RX Bps
      5. Click on Save File and your browser will appear the the HTML copy of the report.
        See also: Full Report     Raw Report Text

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