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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] beckmanf [Results] |
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| 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. | ||