Longtime UDP 100M Test Unstable

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Introduction

In the world of network testing and optimization, UDP (User Datagram Protocol) is a crucial protocol for evaluating network performance. Iperf3 is a popular tool used to measure network bandwidth and latency. However, in some cases, the results may not be as expected, especially when conducting longtime UDP tests. In this article, we will explore a peculiar issue with longtime UDP 100M tests using iperf3.1.8, where the bitrate varies significantly until a certain point in time.

Background

Iperf3 is a widely used tool for network testing, and its UDP mode is particularly useful for evaluating network performance under high-bandwidth and low-latency conditions. The tool allows users to measure network bandwidth and latency, making it an essential tool for network administrators, engineers, and researchers.

The Issue

In this article, we will focus on a specific issue with longtime UDP 100M tests using iperf3.1.8. The issue is characterized by a significant variation in bitrate until a certain point in time, after which the bitrate stabilizes at a consistent value. This issue was observed in two different scenarios:

  1. Scenario 1: Two Windows 10 PCs connected through a switching HUB.
  2. Scenario 2: Two Windows 10 PCs connected directly through a LAN cable.

In both scenarios, the iperf3.1.8 speed test was conducted using the same command:

  • Client PC: iperf3.exe -c --udp --port 5201 --reverse --interval 1 --time 18000 --omit 10 --bandwidth 100M --get-server-output --forceflush | Foreach{"{0}={1}" -f (Get-Date -Format 'yyyy/MM/dd-HH:mm:ss'), $_} | Tee-Object -FilePath "C:\XXX.txt"
  • Server PC: iperf3.exe -s

Results

The results of the iperf3.1.8 speed test in both scenarios are as follows:

Scenario 1: Two Windows 10 PCs connected through a switching HUB

Time Bitrate
0-11000 sec 70-100 Mbps
11000+ sec 100 Mbps

Scenario 2: Two Windows 10 PCs connected directly through a LAN cable

Time Bitrate
0-11000 sec 90 Mbps
11000+ sec 100 Mbps

Analysis

The results of the iperf3.1.8 speed test in both scenarios show a significant variation in bitrate until a certain point in time (approximately 11000 sec). After this point, the bitrate stabilizes at a consistent value (100 Mbps). This behavior is peculiar and requires further analysis to understand the underlying causes.

Possible Causes

There are several possible causes for this behavior:

  1. Network Buffering: Network devices, such as routers and switches, may have buffering mechanisms that can affect network performance. In this case, the buffering mechanism may be causing the bitrate to vary until the buffer is filled or emptied.
  2. TCP/IP Stack: The TCP/IP stack on the client and server PCs may be causing the bitrate to vary. The TCP/IP stack is responsible for managing network connections and may be affecting the performance of the iperf3.1.8 test.
  3. Hardware Limitations: The hardware used in the test may be limiting the bitrate. For example, the network interface cards (NICs) on the client and server PCs may not be able to handle the high-bandwidth requirements of the test.
  4. Software Limitations: The software used in the test may be limiting the bitrate. For example, the iperf3.1.8 tool may not be able to handle the high-bandwidth requirements of the test.

Conclusion

In conclusion, the longtime UDP 100M test using iperf3.1.8 shows a peculiar behavior where the bitrate varies significantly until a certain point in time. This behavior is observed in two different scenarios: two Windows 10 PCs connected through a switching HUB and two Windows 10 PCs connected directly through a LAN cable. The possible causes of this behavior include network buffering, TCP/IP stack, hardware limitations, and software limitations. Further analysis and testing are required to understand the underlying causes of this behavior and to optimize network performance.

Recommendations

Based on the analysis and possible causes, the following recommendations are made:

  1. Optimize Network Configuration: Optimize the network configuration to minimize buffering and maximize network performance.
  2. Upgrade Hardware: Upgrade the hardware used in the test to ensure that it can handle the high-bandwidth requirements of the test.
  3. Use Alternative Tools: Use alternative tools that can handle high-bandwidth requirements and provide more accurate results.
  4. Conduct Further Testing: Conduct further testing to understand the underlying causes of this behavior and to optimize network performance.

Future Work

Future work includes:

  1. Conducting Further Testing: Conducting further testing to understand the underlying causes of this behavior and to optimize network performance.
  2. Analyzing Network Traffic: Analyzing network traffic to understand the behavior of the network devices and the TCP/IP stack.
  3. Optimizing Network Configuration: Optimizing the network configuration to minimize buffering and maximize network performance.
  4. Developing Alternative Tools: Developing alternative tools that can handle high-bandwidth requirements and provide more accurate results.
    Frequently Asked Questions (FAQs) about Longtime UDP 100M Test Unstable ====================================================================================

Q: What is the issue with longtime UDP 100M tests using iperf3.1.8?

A: The issue is characterized by a significant variation in bitrate until a certain point in time, after which the bitrate stabilizes at a consistent value. This behavior is observed in two different scenarios: two Windows 10 PCs connected through a switching HUB and two Windows 10 PCs connected directly through a LAN cable.

Q: What are the possible causes of this behavior?

A: The possible causes of this behavior include:

  1. Network Buffering: Network devices, such as routers and switches, may have buffering mechanisms that can affect network performance.
  2. TCP/IP Stack: The TCP/IP stack on the client and server PCs may be causing the bitrate to vary.
  3. Hardware Limitations: The hardware used in the test may be limiting the bitrate.
  4. Software Limitations: The software used in the test may be limiting the bitrate.

Q: How can I optimize network configuration to minimize buffering and maximize network performance?

A: To optimize network configuration, you can try the following:

  1. Disable Network Buffering: Disable network buffering on the client and server PCs to minimize buffering and maximize network performance.
  2. Adjust TCP/IP Stack Settings: Adjust the TCP/IP stack settings on the client and server PCs to optimize network performance.
  3. Upgrade Hardware: Upgrade the hardware used in the test to ensure that it can handle the high-bandwidth requirements of the test.
  4. Use Alternative Tools: Use alternative tools that can handle high-bandwidth requirements and provide more accurate results.

Q: What are the benefits of using alternative tools for network testing?

A: The benefits of using alternative tools for network testing include:

  1. Improved Accuracy: Alternative tools can provide more accurate results than iperf3.1.8.
  2. Increased Bandwidth Support: Alternative tools can handle high-bandwidth requirements and provide more accurate results.
  3. Better Network Performance: Alternative tools can optimize network performance and minimize buffering.

Q: How can I conduct further testing to understand the underlying causes of this behavior?

A: To conduct further testing, you can try the following:

  1. Analyze Network Traffic: Analyze network traffic to understand the behavior of the network devices and the TCP/IP stack.
  2. Optimize Network Configuration: Optimize the network configuration to minimize buffering and maximize network performance.
  3. Use Alternative Tools: Use alternative tools that can handle high-bandwidth requirements and provide more accurate results.
  4. Develop Alternative Tools: Develop alternative tools that can handle high-bandwidth requirements and provide more accurate results.

Q: What are the future work plans for this project?

A: The future work plans for this project include:

  1. Conducting Further Testing: Conducting further testing to understand the underlying causes of this behavior and to optimize network performance.
  2. Analyzing Network Traffic: Analyzing network traffic to understand the behavior of the network devices and the TCP/IP stack.
  3. Optimizing Network Configuration: Optimizing the network configuration to minimize buffering and maximize network performance.
  4. Developing Alternative Tools: Developing alternative tools that can handle high-bandwidth requirements and provide more accurate results.

Q: How can I get involved in this project?

A: If you are interested in getting involved in this project, you can try the following:

  1. Contact the Project Lead: Contact the project lead to discuss your interest in the project.
  2. Join the Project Team: Join the project team to contribute to the project.
  3. Provide Feedback: Provide feedback on the project to help improve its quality and accuracy.
  4. Develop Alternative Tools: Develop alternative tools that can handle high-bandwidth requirements and provide more accurate results.