iPerf Performance Tests - Application Note | NETSCOUT
Application Note

iPerf Performance Tests with the AirCheck G2 Wireless Tester

This application note describes how to run iPerf Performance Test on the AirCheck™ G2.

It provides guidance on setting up your own iperf3 server, how to use NETSCOUT’s Test Accessory, and how to configure an AirCheck G2 to get the most accurate performance test results.

Introduction

Testing the Wi-Fi network performance in terms of speed and bandwidth is standard practice on both corporate and home environments.

A detailed report of speed and bandwidth analysis is necessary for the deployment of network dependent services. Also, sometimes you need to double check the speed of your network throughput while troubleshooting to make sure you have enough bandwidth to support user applications like Voice over Wi-Fi, Video Streaming, etc. All this requires a reliable network performance testing tool.

Typically, people will use various internet speed tests to verify performance. Still, this is a good way to disappoint yourself and all involved. Internet speed tests are never a guarantee and always rely on not only your internet bandwidth and availability (which can vary depending on usage and load from others), but most importantly the capabilities of the server being used for the speed test.

So, the most accurate way to verify the performance of your network is to use tools that can run locally. This allows you to properly test your environment without relying on someone else’s server to verify that you have adequately designed, deployed, and optimized your Wi-Fi network to support the necessary bandwidth requirements for your users.

Which bring us to the NETSCOUT AirCheck G2 Wireless Tester, a handheld Wi-Fi network test tool that allows you to easily, accurately, and reliably measure the real performance of your Wi-Fi network by providing the option to test against an iPerf3 server.

iPerf Server Installation and Setup

Starting with firmware version 2.0 the AirCheck G2 Wireless Tester will allow you to perform dual ended TCP and UPD performance tests against an iPerf3 server. iPerf3 is an opensource software tool for active measurements of the maximum achievable bandwidth on IP networks. It supports tuning of various parameters related to timing, buffers and protocols (TCP, UDP), and it can now be used with the AirCheck G2 Wireless Tester to run wireless network performance tests through one of the following options:

  • NETSCOUT Test Accessory – This handheld test accessory is a mobile plug and play iPerf3 server, and the easiest way to run a performance test! It’s way easier, especially if you don’t have permissions or time to configure a standalone iPerf3 server.
  • iPerf3 Server Software – Standalone software version of the iPerf3 server can be installed on any computer, but requires manual configuration and setup.

Before you can start testing, you will need to install and setup your NETSCOUT Test Accessory or iPerf3 Server Software using the instructions provided below.

NETSCOUT Test Accessory

The NETSCOUT Test Accessory works together with the AirCheck G2 Wireless Tester to run wireless network performance tests with relative ease. The NETSCOUT Test Accessory acts as an iPerf3 server for tests run by the AirCheck G2 Wireless Tester and can be plugged into any Ethernet port on your network (to verify performance to a remote site, plug the accessory on an ethernet port at the remote site).

The NETSCOUT Test Accessory operates with either Power over Ethernet (PoE) or AA batteries. If you are using batteries only, press and hold the power button for two seconds to turn on the unit. If PoE is available on your network connection, the unit starts up automatically.

As soon as you power on the NETSCOUT Test Accessory, all the LED symbols illuminate yellow for 15 seconds while the unit starts up. Then, the accessory attempts to connect to your ethernet network using DHCP, lighting up each LED with the corresponding connection step. After its done, you are ready to start testing!

Note 1: For more details on the NETSCOUT Test Accessory LED behavior, please refer to the User Guide.

Note 2: If you have an account on NETSCOUT’s Link-Live cloud service, you can claim the NETSCOUT Test Accessory to aid in discovery from your AirCheck G2 Wireless Tester and to download software updates.

Note 3: If a static IP Address or Proxy Server is required, you can use the Web Server Interface on your Test Accessory to change the default configuration. For more details on how to access the Web Server Interface, please refer to the User Guide.

iPerf3 Server Software

For those cases on which a NETSCOUT Test Accessory is not available, you have the option of using the software version of an iPerf3 server. This option will require for you to manually install and configure your own server, but it will provide the same test capabilities and accuracy as a NETSCOUT Test Accessory.

Use the following process to install and setup your own iPerf3 server:

1) Download a copy of the iPerf3 binary to your computer:
  • Use the following link to download the latest version of the software: https://iperf.fr/iperf-download.php
  • iPerf3 is available for Windows, Android, iOS, MAC OS, and Linux. Select the one that applies to your environment.
2) Install the iPerf3 binary on your device:
  • The installation process will vary per operating system. Please refer to the iPerf3 user documentation for details on each operating system (https://iperf.fr/iperf-doc.php). For this Application Note we will be using the Windows version as an example.
    • Using Windows File Explorer find the .zip file that was downloaded on the previous step and double click on it to unzip the file.
    • Copy the uncompressed files into a folder on your computer.
  • If testing the performance of the local network, install the iPerf3 server software on a computer connected to the local network.
  • If testing performance to a remote site, install the iPerf3 server software on a computer connected to the network on the remote site.
3) Run the iPerf3 binary on your computer:
  • The process to run the iPerf3 binary will vary per operating system. Please refer to the iPerf3 user documentation for details on each operating system (https://iperf.fr/iperf-doc.php). For this Application Note, we will be using the Windows version as an example (see images below).
    • Open a Windows Command Prompt.
    • While on the Command Prompt window use the ‘CD’ command to navigate to the folder on which the iPerf3 binary was saved. For example: CD Users\Administrator\Downloads\iperf-3.1.3-win64
    • Type the command iperf3 -s and hit Enter on your keyboard. This will start the iPerf3 application on Server mode.
    • Windows may ask if you want to allow the iPerf3 application to communicate through the firewall (will depend on the version of Windows being used). Allow this communication by selecting the appropriate option.
    • A message will show up on the Windows Command Prompt saying, ‘Server listening on 5201’. You are now ready to start testing!
  • Even though it is possible to run the iPerf3 server binary from a computer on the wireless network, this setup may not give you a true representation of your network’s performance. It is recommended to run the iPerf3 server software from a computer on the wired ethernet network. This will provide visibility on not only how the wireless network is performing, but how the performance is affected by the wired backhaul.

Figure 2: Examples of the CD and iperf3 -s commands on the Windows Command Prompt

Figure 3: Example of iPerf3 Server running on the Windows Command Prompt

Note 4: The iPerf3 Server software will use the IP address of the device on which it was installed. Please make a note of this information since the IP address of the iPerf3 Server will be required during the AirCheck G2 Wireless Tester performance test setup.

AirCheck G2 Setup

After the NETSCOUT Test Accessory or the iPerf3 Server is ready, you have the option to change the setup on your AirCheck G2 Wireless Tester before you start testing. To change the default performance test settings on your AirCheck G2 Wireless Tester, do as follows:

  • Press the Power button on your AirCheck G2 Wireless Tester to turn on the unit.
  • After the unit finishes booting up, use the touchscreen to select the Settings option.
  • Using the touchscreen, scroll through the options and then select iPerf Settings.
4) You will now be given the option to change many of the settings related to the iPerf performance test that the AirCheck G2 Wireless Tester can run against the NETSCOUT Test Accessory or an iPerf3 Server.
  • Protocol – Allows you to select between TCP or UDP tests.
    • TCP – Used to measure bandwidth. Use this option when you want to measure the throughput of your wireless network.
    • UDP – Used to measure packet loss and jitter. Use this option when you want to troubleshoot problems with latency sensitive application like Voice over Wi-Fi.
  • Port – Used to change the port on which the test will be performed. The default port used is 5201. This is also the default port used by the NETSCOUT Test Accessory or the iPerf3 Server.
  • Test Duration – Shows the selected duration for the entire iPerf test run, with half of the time for the upload portion and half for the download portion of the test. The default value is 20 seconds, and it can be changed to 60 seconds or 120 seconds. A longer test will give a more accurate view of your average network performance.
  • Accessory Battery Type – This setting allows the AirCheck G2 Wireless Tester to display the battery level status of your NETSCOUT Test Accessory accurately. The battery type options supported are Alkaline, Lithium, and NiHM.
  • Thresholds – This option is a shortcut to the Thresholds screen, and allows you to change the Pass/Fail thresholds for Target Speed, Loss Percentage, and Jitter. The default values are based on industry standards, but you can change them to match your local network requirements.

5) After making changes to the settings press the Apply button to save them.

Running a Performance Test

Running a performance test on the AirCheck G2 Wireless Tester is a very simple process. To run a test, do the following:

  • From the Home screen use the touchscreen to select the Networks or Access Points option. The Networks option will allow you to select an SSID you want to test. Meanwhile, the Access Points option will allow you to test a specific access point. For this Application Note, we will use the Networks option as part of our example.
  • From the Networks screen, use the touchscreen to select the SSID on which you want to run the performance test. If you decided to use the Access Points option, then you need to select an access point.
  • After selecting the SSID or Access Point on which you want to run the performance test, you will get to the details screen. This screen will provide details about the selected SSID or Access Point and will allow you to run a connection test. Using the touchscreen, press the Connect button.
  • After the connection test is completed successfully, you will be given the option to run a performance test. Using the touchscreen, press the iPerf Test button.
  • Under the Select iPerf Server screen you will be given the option to select a NETSCOUT Test Accessory or iPerf3 Server against which you want to run the performance test. Using the touchscreen, select the server you want to use and then press the Start button to commence your test.
    • If you are using a NETSCOUT Test Accessory to run your test, it will automatically show up under the Available iPerf Remotes list. If there is more than one accessory connected to the network, all of them will show up on the list.
      • After you select a test accessory the IP address under the iPerf Server field will be updated automatically to reflect the address of the test accessory.
      • If a test accessory had been used in the past to perform a test but its currently offline, it will be greyed out on the list.
      • The following information will be available for each test accessory:
        • Test Accessory Name, can be changed after claiming your accessory on Link-Live.
        • IP Address, as assigned by the DHCP server. A static IP address can be assigned through the test accessory’s Web Server Interface too. Please refer to the NETSCOUT Test Accessory user guide for details.
        • Transmission speed of the ethernet port being used.
        • Battery level status for the test accessory.
        • Link-Live status will be represented with a small Cloud icon. If the test accessory has been claimed on Link-Live, then the Cloud icon will show up.
      • The AirCheck G2 Wireless Tester will use multiple methods to detect test accessories:
        • Automatically search the Subnet being used by the access point on which the connection test was performed.
        • Automatically access the IP address and Subnet information of the test accessory through Link-Live. This option will only be available if both the AirCheck G2 Wireless Tester and the NETSCOUT Test Accessory being used for the test have access to internet and have been claimed under the same Link-Live account.
        • Manually provide the Subnet information for the network to which the test accessory has been connected. This can be done by using the touchscreen to select the Additional Subnet field and then using the on-screen keyboard to type the Subnet information.
    • If you are using an iPerf3 Server to run your test, you will need to specify the server’s IP address manually. To do this, use the touchscreen to select the iPerf Server field and then use the on-screen keyboard to type the server’s IP address.

Note 5: For more information on how to access Link-Live and how to Claim a product, please refer to the User Guide of the product in question.

Note 6: If you want to refresh the list of NETSCOUT Test Accessories, under the Select iPerf Server screen, use the touchscreen to press the Rescan button.

Reviewing your Test Results

After the performance test has been completed its time to review the results provided by the AirCheck G2 Wireless Tester. Notice that the performance test results provided will vary depending on the Protocol (TCP, UDP) you selected while configuring the AirCheck G2 Wireless Tester.

TCP Test Results

While using the TCP protocol for your performance test, you will get the following test results:

  1. BSSID – MAC address of the wireless network connection.
  2. SSID – Name of the wireless network connection.
  3. iPerf Server Address – IP address of the NETSCOUT Test Accessory or iPerf3 Server used for the performance test.
  4. Avg. Up Speed – Average upload throughput speed achieved during the test. This is used to determine the average-upload-speed capabilities of your wireless network.
  5. Max Up Speed – Maximum upload throughput speed achieved during the test. This is used to determine the maximum-upload-speed capabilities of your wireless network.
  6. Avg. Down Speed – Average download throughput speed achieved during the test. This is used to determine the average-download-speed capabilities of your wireless network.
  7. Max Down Speed – Maximum download throughput speed achieved during the test. This is used to determine the maximum-download-speed capabilities of your wireless network.
  8. PHY Data Rate – Physical Data Rate measured during the test.
  9. Signal Level – Signal level for the BSSID you are connected to as measured during the test.
  10. Noise Level – Noise level for the BSSID you are connected to as measured during the test.
  11. SNR – Signal-to-Noise Ratio for the BSSID you are connected to as measured during the test.
  12. Retry Rate – Frame Retry Rate for the BSSID you are connected as measured during the test.

Note 7: The “AirCheck G2 Wireless Tester” can measure a “Max Speed” of up to approximately 250 Mbps. If you see an icon with an ‘i’ next to the Max Speed test results, this means that the AirCheck G2 Wireless Tester hardware may be limiting the maximum speed measurement. This is not an error, it just means that your “Max Speed” is higher than what the “AirCheck G2 Wireless Tester” can measure.

UDP Test Results

While using the UDP protocol for your performance test you will get the following test results:

  1. BSSID – MAC address of the wireless network connection.
  2. SSID – Name of the wireless network connection.
  3. iPerf Server Address – IP address of the NETSCOUT Test Accessory or iPerf3 Server used for the performance test.
  4. Upload Speed – Average Throughput measured during the upload test. By default, a target bandwidth of 5.0 Mbps will be used.
  5. Upload Jitter – Average upload Jitter measured during the test.
  6. Upload Loss – Percentage of frames lost during the upload test.
  7. Download Speed – Average Throughput measured during the download test. By default, a target bandwidth 5.0 Mbps will be used.
  8. Download Jitter – Average download Jitter measured during the test.
  9. Download Loss – Percentage of frames lost during the download test.
  10. PHY Data Rate – Physical Data Rate measured during the test.
  11. Signal Level – Signal level for the BSSID you are connected to as measured during the test.
  12. Noise Level - Noise level for the BSSID you are connected to as measured during the test.
  13. SNR – Signal-to-Noise Ratio for the BSSID you are connected to as measured during the test.
  14. Retry Rate – Frame Retry Rate for the BSSID you are connected as measured during the test.

Note 8: Jitter measures the time difference in packet arrival time. A high Jitter will not affect normal wireless transactions, but it will adversely affect Voice over Wi-Fi communications.

Conclusion

In conclusion, it is now easier and faster than ever to verify that your wireless network can support the bandwidth required for Voice over Wi-Fi, Video Streaming, Data Transfers and more. Just plug your NETSCOUT Test Accessory anywhere on your network, take your AirCheck G2 Wireless Tester to the area on which you want to run your performance test, and in a matter of seconds you will be able to measure both your upload and download throughput speeds. No need for complicated and time-consuming setups, and no need to depend on unreliable internet speed tests that could provide inaccurate bandwidth information. Testing, troubleshooting, and verifying performance on your Wi-Fi network has never been easier!

References

You can find the documentation referenced on this Application Note through the following links:

  1. AirCheck G2 Wireless Tester User Manual https://enterprise.netscout.com/findit/7001137
  2. NETSCOUT Test Accessory User Guide https://enterprise.netscout.com/findit/7002071
  3. iPerf3 Binary Downloads https://iperf.fr/iperf-download.php
  4. iPerf3 User Guide https://iperf.fr/iperf-doc.php
  5. Link-Live Sign In https://new.link-live.com/public/login