[Cerowrt-devel] [Make-wifi-fast] [Babel-users] perverse powersave bug with sta/ap mode

Dave Taht dave.taht at gmail.com
Thu Apr 28 12:52:56 EDT 2016

On Thu, Apr 28, 2016 at 9:05 AM, Henning Rogge <hrogge at gmail.com> wrote:
> On Thu, Apr 28, 2016 at 5:04 PM, moeller0 <moeller0 at gmx.de> wrote:
>>> On Apr 28, 2016, at 15:43 , Toke Høiland-Jørgensen <toke at toke.dk> wrote:
>>> Presumably the access point could transparently turn IP-level multicast
>>> into a unicast frame to each associated station? Not sure how that would
>>> work in an IBSS network, though... Does the driver (or mac80211 stack)
>>> maintain a list of neighbours at the mac/phy level?
>> I believe the openwrt developers are thinking a long similar lines, see e.g. https://lists.openwrt.org/pipermail/openwrt-devel/2015-June/033398.html
> Why not just sending IP multicast (not 802.11 management frames) with
> a higher rate (lowest best linkspeed to all known neighbors)?

)I've always liked this idea as an enhancement to the existing 802.11
spec. It is flawed in that the "lowest best linkspeed" in minstrel
decays to the lowest configured link rate for stations that have not
been sampled recently. (Another thing I like about unicast IHU is that
it would keep minstrel's statistics more current). I don't deeply how
other rate controllers besides the old "samplerate" work - and only
just last week finally put the minstrel paper up to review -
(http://blog.cerowrt.org/post/minstrel/). If there are other documents
on wifi rate controllers out there, like those in certain wifi chips,
I'd love to read them....

And: I have found several devices in the field that cannot take
anything but the base multicast rate, my old nexus 7 was like that.

I note I'm not seeking a solution for ND/RA/ARP at the moment - in
fact I'm trying to work on something other than routing protocols
entirely ! - I would like it if people would stop trying to treat wifi
as an ethernet equivalent and treat it as the now dominant paradigm it
is, where ethernet is the exception rather than the rule, ethernet
fallback as a "nice to have" rather than a necessity. For years I got
along just fine on wifi + ethernet using the then common ahcp/babeld
single ip methods ( http://blog.cerowrt.org/post/failing_over_faster/

I am unfond of turning formerly all multicast protocols into unicast,
on wifi,  as proposed for openwrt and for that matter, in the ietf.

This might make for some background reading:

Anyway, I put a couple pictures up at
http://blog.cerowrt.org/post/poking_at_powersave/ - I have some data
showing the ap/sta metric going to hell over a few minutes not in that
post yet and I still ended up with some difficulties (I have not
turned powersave off everywhere yet, repeatably, as I need to find the
right hooks to tell Ap/sta mode in
networkmanager/systemd/debian/openwrt to turn it off. (?)) - did I say
I wasn't working on meshy protocols already? :grump:

and I have a conference today and more new gear arriving to play with.

> Henning Rogge
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> Make-wifi-fast at lists.bufferbloat.net
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Dave Täht
Let's go make home routers and wifi faster! With better software!

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