[Make-wifi-fast] deep wifi

[Dave Taht]

On Mon, Aug 27, 2018 at 8:32 PM David Lang <david at lang.hm> wrote:
>
> Think of the DoS possibilities if you can tell other networks to not transmit.

Actually, that's a thing. google for "ap suppression".




> David Lang
>
>
> > On Mon, Aug 27, 2018 at 6:56 PM Bob McMahon <bob.mcmahon at broadcom.com> wrote:
> >>
> >> Hmm, not sure I understand the distinction.   CTS per the AP informs those other transmitters to stay quiet per the CTS NAV.  I may be misunderstanding things.  Thanks for the continued discussions.  It helps to better thoroughly understand the issues.
> >>
> >> Bob
> >>
> >> On Mon, Aug 27, 2018, 6:52 PM David Lang <david at lang.hm> wrote:
> >>>
> >>> On Mon, 27 Aug 2018, Bob McMahon wrote:
> >>>
> >>>> I thought that RTS/CTS would handle the case of hidden nodes, i.e. a device
> >>>> that fails to successfully transmit can resort to RTS/CTS to get the
> >>>> receiver to reserve time for it.  Also, lack of a RX ack seems ok to
> >>>> trigger MAC level retransmits.
> >>>
> >>> the problem isn't getting the receiver to reserve time for it, it's getting the
> >>> other transmitter(s) to not step on it when it transmits. Those other
> >>> transmitters may belong to different people, sharing a channel with your system
> >>> and nothing else.
> >>>
> >>> David Lang
> >>>
> >>>> It seems the LBT bug is the collision avoidance overheads when it isn't
> >>>> needed, i.e. no other energy would cause the RX PHY to fail its decode and
> >>>> the EDCA backoffs had no benefit, stochastic or otherwise.   Optimizing
> >>>> that out is said to be not possible from local information only and per
> >>>> "shared" spectrum.
> >>>>
> >>>> Bob
> >>>>
> >>>>
> >>>> On Mon, Aug 27, 2018 at 3:33 PM David Lang <david at lang.hm> wrote:
> >>>>
> >>>>> On Mon, 27 Aug 2018, Jonathan Morton wrote:
> >>>>>
> >>>>>> So in practice, it's easier to measure SNR at the receiver, or
> >>>>> indirectly by
> >>>>>> observing packet loss by dint of missing acknowledgements returned to
> >>>>> the
> >>>>>> transmitter.
> >>>>>
> >>>>> Also, there may be other transmitters that the recipient of the packets
> >>>>> can hear
> >>>>> that you cannot hear, so it's not possible to detect colliding
> >>>>> transmissions
> >>>>> directly in all cases.
> >>>>>
> >>>>> This is another trap that digital/wired people fall into that doesn't
> >>>>> really
> >>>>> apply in the analog/radio world.
> >>>>>
> >>>>> David Lang
> >>>>>
> >>>>
> >>
> >> _______________________________________________
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> >> Make-wifi-fast at lists.bufferbloat.net
> >> https://lists.bufferbloat.net/listinfo/make-wifi-fast
> >
> >
> >
> >



-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619