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Network Testing and Emulation Solutions

WiFi Capacity Test with Layer 4

Goal: Use the WiFi Capacity Test plugin to emulate layer 4 traffic from ten virtual stations across an access point and report the results.

Requires 5.2.13 or later. This cookbook will go through setting up a VAP (Virtual Access Point) as an HTTP server, and creating/configuring 10 virtual stations to communicate with the VAP. It will also go through the setup of the WiFi Capacity Test LANforge-GUI plugin to have the virtual stations emulate downloading a file using Layer 4 endpoints in LANforge.

This example uses a LANforge CT523 system but the procedure should also work on a CT524, CT525 or similar system.

 
  1. Create a VAP.

    1. Verify the wiphy device used for the VAP is on your preferred channel (this test will use channel 11).

      1. In the Port Mgr tab of the LANforge Manager, modify the wiphy device that'll be used for the VAP (wiphy0 in this test). screenshot

        1. Select your preferred channel here.

      2. Make sure the wiphy device is up. screenshot

        1. If the device is down like in the above screenshot, select it and click the Admin UP button (also indicated in the above screenshot).

    2. In the Port Mgr tab, select a wiphy device (wiphy0 in this test) and click Create. screenshot

      1. Select the WiFi VAP radio button.

      2. Set Quantity to 1.

      3. Set STA ID to 0.

      4. Set IP Address to 10.0.0.1/24.

      5. Set the SSID to layer4test.

      6. Click Apply and close the create port window.

    3. Configure the VAP.

      1. Open Netsmith from the Status tab. screenshot

      2. In Netsmith, right click and select New Router.

      3. Click OK.

      4. Drag vap0 into the virtual router. screenshot

      5. Right click vap0 and select Modify.

      6. Check DHCP.

      7. Change DHCP Range Min to 10.0.0.10

      8. Change DHCP Range Max to 10.0.0.50

      9. Click OK. screenshot

      10. Click Apply in Netsmith then close the window.

  2. Create 10 virtual stations.

    1. Verify the wiphy device used for the stations (wiphy 2 in this test) is on the AUTO channel. screenshot

    2. Make sure wiphy2 is up. screenshot

    3. In the Port Mgr tab, select a wiphy device (wiphy2 in this test) and click Create. screenshot

      1. Select the WiFi STA radio button.

      2. Set Quantity to 10.

      3. Set STA ID to 0.

      4. Select DHCP-IPv4.

      5. Set the SSID to layer4test.

      6. Click Apply and close the create port window.

    4. Make sure the 10 staX ports get IPs. screenshot

  3. Create a file for the layer 4 endpoint to use.

    1. In a terminal on the LANforge system, run the below command to generate a 10MB file in /home/lanforge.
      Note: The smaller a file is, the harder it is to reach higher rates. Therefore it is recommended to use a larger file for these tests.

      dd if=/dev/urandom of=/home/lanforge/large-file.bin bs=1k count=10240

      screenshot

    2. For the webserver to serve the file we created, it needs to know where to find it. Run the below command in a terminal on the LANforge system to link the file.

      ln -s /home/lanforge/large-file.bin /usr/local/lanforge/nginx/html

      screenshot

  4. Set up the HTTP server on vap0.

    1. Before starting HTTP on vap0, the Apache service may need to be disabled.

      1. Stop and disable httpd (Apache) in the LANforge terminal with the below commands.
        sudo systemctl stop httpd.service
        sudo systemctl disable httpd.service
        sudo systemctl daemon-reload
        screenshot

      2. Modify vap0 in the LANforge Port Mgr tab.

        1. Enable the HTTP checkbox. screenshot

        2. Click OK.

  5. Create a layer 4 endpoint. WiFi Capacity will be using this as a template to copy from.

    1. In the Layer-4 tab, click Create. screenshot

      1. Set the Name to l4-http

      2. Set the Port to sta0.

      3. The URL will point to the VAP's IP: http://10.0.0.1/large-file.bin
        Note: This is where you can specify an IP of an AP you wish to test. LANforge also supports other layer 4 protocols, for more information you can view a tooltip by hovering over the URL text box.

      4. Set the Source/Dest File to /dev/null

      5. Click OK.

  6. Set up and run a WiFi Capacity test.

    1. Select the 10 created stations, then open WiFi Capacity Test from the Plugins menu. screenshot

    2. Go to the Settings tab. screenshot

      1. Set Station Increment to 1.

      2. Set the Protocol to Layer-4. Note: This should automatically be set if you first select a Layer-4 Endpoint.

      3. Select your Layer-4 Endpoint (l4-http in this test). The capacity test will use this as a template for each of the ten stations.

      4. Total Rate can stay at 10Mbps. Note: This rate can represent either upload or download traffic depending on how you have your layer 4 endpoint configured.

    3. Run the Capacity test by clicking Start. screenshot

      1. The test will now make a copy of the selected layer-4 endpoint for each station. Note: You may notice that URLs per 10m is set to a high rate, this is to ensure the maximum amount of URLs are processed as WiFi Capacity adjusts the Max Speed.


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