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searchwing-pi-datarate [2019/11/27 17:10]
beckmanf [http transfer time for wifi]
searchwing-pi-datarate [2020/01/08 22:00] (current)
beckmanf [Results]
Line 484: Line 484:
  
 The transfer times for the 100MB were 30s, 24s, 25s, 26s. This corresponds to a transfer rate of 30 MBit/s. Some times for the 1MB file were: 0.2 0.2 0.2 0.9 0.3 0.7 0.7 0.2 -> There is heavy congestion on channel 1. The transfer times for the 100MB were 30s, 24s, 25s, 26s. This corresponds to a transfer rate of 30 MBit/s. Some times for the 1MB file were: 0.2 0.2 0.2 0.9 0.3 0.7 0.7 0.2 -> There is heavy congestion on channel 1.
 +
 +Based on the 0.2s for the 1 MB File, this translates to **5 MB/s = 40 MBit/s** rate for an undisturbed channel for a transfer via http. This is again exactly the achieved iperf rate as shown above.
 +
 +==== Julian tests ====
 +
 +  * WIFI Only datatransfer
 +  * Router: FritzBox 7430 AW
 +  * Placement: Pi Zero and Laptop placed 10cm above router.
 +  * data ammount: 540 MByte
 +  * ** Laptop and Raspberry Pi share the same Wifi channel => Each packet goes from Pi to AP and from AP to Laptop. => Congestion on the Wifi Channel. **
 +
 +=== wget ===
 +  * time=213sek
 +  * rate=2.53 Mbyte/sek
 +  * cpuusage=70%
 +
 +=== ftp ===
 +  * time=361sek
 +  * rate=1.495 Mbyte/sek
 +  * cpuusage=50-60%
  
 ==== Results ==== ==== Results ====
  
 +  * The Laptop and the Pi should not be connected via a single 2.4 GHz access point as laptop and Pi share the same Wifi channel. This results in 50% throughput reduction (see Julians 2.5 MB/s for wget).
 +  * The transfer rate via wget on an undisturbed 2.4 GHz wifi channel is **5 MB/s**. (Only Pi connected to AP, No other stations use this channel). This 40 MBit/s throughput on http level compares well to the maximum 65 MBit/s wifi data rate of the Pi Zero W.
 +  * ssh transfer is limited by CPU load on the Pi for encryption and results in 1.8 MB/s for Wifi.
 +  * Short Guard Interval setting could possibly increase the the raw wifi rate from 65 MBit/s to 72 MBit/​s. ​
  
  
  • searchwing-pi-datarate.1574871012.txt.gz
  • Last modified: 2019/11/27 17:10
  • by beckmanf