Re: [PATCH] batman-adv: Use wifi rx/tx as fallback throughput

Marek Lindner
2019-06-25T08:26:32Z

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On Thursday, 13 June 2019 04:50:44 HKT Кирилл Луконин wrote:
> So here is the algorithm. It has a structure we call matryoshka.
> ET - Expected_throughput.
>
> 1) ET = TX_bitrate * Transmit_probability * Overhead_coefficient
> Transmit_probability is always less than 1 so Expected throughput
> can't be equal to the TX_bitrate. Overhead_coefficient is also should
> be less than 1
>
> 2) Transmit_probability = 1 - Retry_probability - Error_probability
>
> 3) Retry_probability = TX_retries / TX_packets
>
> 4) Error_probability = TX_errors / TX_packets
>
> 5) Overhead_coefficient for 802.11 is fair enough to be 0.65, but can
> be changed after additional testing.
>
>
> ET = TX_bitrate * (1 - (TX_retries + TX_errors) / TX_packets) * 0.65
> Such technique has very large hysteresis which is good to avoid
> flapping between different nodes.
> In my MESH lab this formula works quite well.

This looks like an interesting approach. Which chips / environments did you
test this formula with and how did the result compare to the actual TCP
throughput ?

Thanks,
Marek

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