You are here

Turning off LQM

3 posts / 0 new
Last post
Turning off LQM
Turing off LQM on the advanced configuration page of AREDN brings up a selection box for "Maximum packet size".
It does not seem to be a requirement to make this selection so I did not.  Eventually I noticed that there is a "set to default" button and clicked that.

The default is a packet size of 1500. 

My question is about what is the consequence of not selecting a Maximum packet size?

Secondarily, are there benefits to tuning the packet size that are reflected on some performance metric?

Thanks for any comments,

*** Ben KE3KQ
KA7HAK's picture
Not Selecting a Maximum Packet Size

When you do not select a Maximum packet size in the AREDN (Amateur Radio Emergency Data Network) advanced configuration, the system may either use a default value or could potentially result in suboptimal performance due to packet fragmentation or inefficiency in data transmission. Here are the key points to consider:

Consequences of Not Selecting a Maximum Packet Size:

  1. Default Value: The system may use a default value (which appears to be 1500 bytes in your case). This is a standard Ethernet frame size (MTU - Maximum Transmission Unit).
  2. Packet Fragmentation: If the packet size is too large for the network path, it may lead to fragmentation, where large packets are broken down into smaller ones to traverse the network, causing overhead and potential performance degradation.
  3. Compatibility Issues: Some network devices or paths may not support larger packets. If the MTU is not optimized, it could lead to dropped packets or connectivity issues.

Benefits of Tuning the Packet Size:

  1. Optimized Throughput: Properly setting the MTU can maximize throughput and minimize latency. Smaller packets might reduce efficiency due to overhead, while too large packets might suffer from fragmentation.
  2. Reduced Latency: Adjusting the packet size can help reduce latency, especially in scenarios where there are multiple network hops or varied network links.
  3. Improved Reliability: By avoiding fragmentation, you can improve the reliability and stability of the network connection.

Performance Metrics Reflecting MTU Tuning:

  1. Latency: Measure the round-trip time (RTT) for packets to ensure there is no unnecessary delay.
  2. Throughput: Monitor the data transfer rate to see if changes in packet size affect the overall bandwidth utilization.
  3. Packet Loss: Check for any increase in packet loss which might indicate problems with packet size configuration.
  4. Fragmentation Statistics: Some network monitoring tools can provide statistics on packet fragmentation which can help in tuning the MTU.

Practical Steps to Tune Packet Size:

  1. Ping Tests: Use ping tests with different packet sizes to determine the optimal MTU. For example, use ping -s with increasing sizes until you start seeing packet fragmentation.
  2. Monitoring Tools: Utilize network monitoring tools to observe the impact of different MTU settings on network performance metrics.
  3. Gradual Adjustment: Start with the default value and make gradual adjustments while monitoring performance to find the optimal setting.

By carefully tuning the MTU, you can enhance network performance, improve reliability, and ensure efficient data transmission across the AREDN network.

Re your comment on packet size selection:
What a thoughtful and complete comment.  Very nicely done.


Theme by Danetsoft and Danang Probo Sayekti inspired by Maksimer