[maemo-users] Steve's Ranty Review #1: N800 ogg support

From: Frédéric Crozat fred at crozat.net
Date: Sat Oct 27 18:38:31 EEST 2007
Le jeudi 25 octobre 2007 à 08:05 +0300, Kalle Valo a écrit :
> ext Frédéric Crozat <fred at crozat.net> writes:
> >> o Buggy AP which does not support WLAN PSM properly.
> >
> > My AP (Freebox, an ISP set-top-box) seems to support WLAN PSM
> > properly.
> If you have problems WLAN standby times I'm not yet convinced that
> your AP work correctly.

After more tests, it appears both my AP don't support full PSM :(
> > I also have a Fonera. Is there any way to check, from n800 side, if WLAN
> > PSM isn't working properly ? (I've enabled full PSM and pings are still
> > working)
> Usually I first try that unicast is working correctly with ping from
> network (execute this from a PC connected to the AP, either with
> Ethernet or WLAN):
> ping -i 2
> Next I will check broadcast with arping (also from a PC, need to be in
> same in subnet):
> arping -I eth0 -b
> Packet loss should be zero percent in both cases. 
> Next I measure the power consumption, but one needs special hardware
> for that. Unfortunately I don't have any ideas how you could do that.

Maybe in future kernel some info in sysfs ? :)

> If I spot any problems with these tests, I use a wireless sniffer for
> analysis. I have found that madwifi driver and Wireshark are the most
> suitable for me.

Unfortunately, I don't have PC with wifi at home.

Anyway, I've used your tests with full PSM and it appears both Freebox
and Fonera (as noticed by Riku in another reply) have problems with
it :(

I've taken the liberty to write a summary of the various informations
you gave here about PSM and how to change it on Maemo wiki. Feel free to
fix errors I might have introduced :

> >> o Lots of broadcast and multicast packets on the network (like
> >>   Windows samba broadcasts).
> >
> > No Windows (nor Samba) on the network.
> >
> > However, I tried to run tcpdump on n800 to see what is going on.
> >
> > It seems Nintendo Wii "standby mode" is causing arp and DNS query, seen
> > on n800, every 10 minutes.
> If it's only one ARP and DNS query, every 10 minutes is not that bad.
> Just of curiosity, who is issuing the DNS query? The Nintendo Wii
> device? N800 shouldn't see DNS requests made by other devices. DNS is
> unicast and N800 shouldn't see unicast packets between AP and other
> WLAN clients.

I'll check again.

> > Since I have two AP available, I'll try to configure both n800 and Wii
> > to use separate networks, to check if it improves situation.
> Good idea.

I tried disabling Wii and it didn't bring any improvement, since PSM is
really a problem for both my AP. I'll contact my ISP for the AP inside
Freebox, maybe they can do something about it (it is using Ralink 2661

> > Can we expect any improvement when changing WLAN power from 100mA to
> > 10mA ? 
> I have been told that it doesn't affect much (if at all). I recommend
> not to try that, it's not worth it. We have implemented it for
> regulatory purposes.

Good to know.
Frédéric Crozat 

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