[Battlemesh] idea: QoS in mesh-networks / private interfaces

Benjamin Henrion zoobab at gmail.com
Wed Apr 13 08:11:11 UTC 2016


On Mon, Apr 11, 2016 at 9:37 PM, Dave Taht <dave.taht at gmail.com> wrote:
> On Mon, Apr 11, 2016 at 12:19 PM, Bastian Bittorf
> <bittorf at bluebottle.com> wrote:
>> dear hobbyists!
>>
>> For making everything better 8-) my idea was to
>> apply QoS-rules per neighbourm, because of:
>
> I am in the middle of a long writeup on why classic 802.11e QoS ideas
> are flawed and how to go about fixing some of them, as yet
> unfinished.... however I do have some pieces already in the queue that
> I hope will help, some links below.
>
> However the way you are using "QoS" here is not how I would
> conventionally think of Qos.
>
>>
>> dynamically restrict rx/tx to _lower_ values than rate-selection
>> guesses, so we dont run that likely into congestion/borders.
>
> Actually, you will make congestion worse this way, generally.
>
> http://blog.cerowrt.org/post/selective_unprotect
>
>> yes: i prefer low latency over fast throughput.
>
> So do I!
>
> However, some packet loss or congestion management is needed to
> actually match the rate to the throughput. Having a more perfect rx/tx
> is sometimes the opposite to what you really want.
>
> Secondly, things like minstrel optimize for the best connectivity, and
> perversely, sometimes the high rate has less interference, shorter
> packets using less airtime is better, or being sent twice in the retry
> chain, is often better than the lower rate. The paper on how minstrel
> worked (in 2008) I have finally got around to putting up, here:
>
> http://blog.cerowrt.org/post/minstrel/
>
> I wish everyone deeply involved in wifi had had a core starting point,
> there. Grokking rate control is a big piece of the puzzle.

A suggesting for WBM tests would be to force the bitrate to a certain
value. Leaving to "auto" mode might mean that you have to log at which
bitrate the radio associates, and if it varies through time (for ex if
there is traffic).

Same remark for the TXpower, leaving it at 18dbm while you do indoor
tests is just insane.

-- 
Benjamin Henrion <bhenrion at ffii.org>
FFII Brussels - +32-484-566109 - +32-2-3500762
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