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

From: Kalle Valo Kalle.Valo at NOKIA.COM
Date: Thu Oct 25 08:05:22 EEST 2007
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.

> 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.

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.

>> o distance to AP (WLAN background scan will kick in if the signal level is
>>   -75 dBm or less)
> Not a problem here, I'm in about 2 to 5 meters of AP.

Ok, background can be ruled out.

>> 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.

> 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.

> 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.

Kalle Valo

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