Re: Fwd: p54: testing AP mode: cannot switch to master mode

["Stefan Steuerwald" <salsasepp@googlemail.com>]

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>> What's your client? Is it using powersave? Anyone know whether
>> multicast-after-dtim works correctly in p54? Or maybe there's a bug
>> hitting with TIM bits? Do you have an extra card that you could use to
>> monitor and see what happens when it times out?
>
> I have tested multiple clients at this time with my XG-601/ISL3880 p54 card:
> - iPod Touch 2G with firmware 2.1.1
> - Sony Vaio with a Marvell 88E8036 (Vista SP1)
> - Amilo Notebook with Intel 4965AGN (stock Ubuntu 8.10)
> - Amilo Notebook with Netgear USB-WLAN-Stick with RTL8187B (stock Ubuntu 8.10)
>
> Interestingly, only the iPod is unusable, with constant timeouts of my
> web-app. The other clients work 99% of the time with an _occasional_
> timeout. I have multiple clients connected at the same time, and never
> saw a simultaneous timeout with any two clients. I have also a wired
> reference connection which never exhibits any timeouts.

I have attached some traffic dumps that happen between my iPod Touch
and the XG-601-based AP (obtained with a RTL8187B in monitor mode):

Observations:

- ipod_http_request_ok.pcap shows how I would like the world to be
(and how it is _occasionally_ with the iPod and _almost always_ with
my other clients). We build a TCP connection, make a http request, get
a TCP ACK, followed swiftly by an answer and the TCP connection
closes.

- Sometimes, however, the http answer does not appear immediately
after the request (about 4-7 secs of delay). The gap is filled by some
"Null function" packets originating on the iPod (maybe it is getting
impatient?). This gets me an application-level timeout. See
ipod_http_request_delayed_answer.pcap .

- Then, there's a scenario that makes the iPod reset any new TCP
connection until I disassociate and reassociate it to the AP (see the
last two pcaps). This seems to happen whenever somebody (must be my
Notebook WLAN) sends probes. The same sequence of events does not
cause anything untoward with my other clients.

It may be Apple's job to fix this - however, iPods work ok with many
APs (including Apple's own AirPort of course) (and the latest madwifi
except for annoying "stuck beacons" resulting in card resets).

Any ideas? Should I forward this info to someone? Anything I should try?
My goal is to make the iPod work with any decent MiniPCI card that
supports AP mode.

Best regards,
  Stefan.

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