hostap/linux + airport extreme problems

[Michael Sharman]

Hi,

Has anyone got any tips for configuring a Linux + hostapd based  
access point that will work with Apple Airport Extreme cards?

Presently I've got a setup that works fine with many PC based  
wireless cards but seems to be very unreliable with an Apple AIrport  
Extreme wireless card as a client;  the Airport Extreme cards  
associate  but a ping shows only every second packet at best getting  
through, this makes networking extremely slow and unreliable often  
leading to the connection dropping out completely.

The access point hardware is the following:
	- Pentium 200 MMX aith 96Mb of RAM running Debian Sarge with a  
custom 2.6.16 compiled kernel
	- D-Link DWL-650 11Mbps WLAN Card in a PCMCIA to PCI adaptor

The clients:
	- Mac OS 10.4 (PPC) iBook G4, Airport Extreme; associates but  
doesn't maintain reliable connection, after a period of time  
disassociates
	- Mac OS 10.4 (Intel) Macbook, Airport Extreme; associates but  
doesn't maintain reliable connection, after a period of time  
disassociates
	- WIndows XP Dell laptop, built in wireless; works flawlessly.
	- PC Desktop, Celeron, Debian sid, Belkin F5D6001au wireless card  
(using the open source drivers; http://rtl8180- 
sa2400.sourceforge.net/) kernel 2.6.16; works flawlessly

So far it's only been the airport extreme cards that I've had any  
issues with, the other cards work fine, this leads me to believe I  
don't have a configuration error...

Currently I'm not running the user space hostapd daemon, and have the  
following config on the wireless card (/et/c/network/interfaces):

iface wlan0 inet static
         wireless-mode master
         wireless-essid LJH49
         address 192.168.2.254
         netmask 255.255.255.0
         network 192.168.2.0
         broadcast 192.168.2.255

Example ping:

michaels-computer:~ michael$ ping 192.168.2.254
PING 192.168.2.254 (192.168.2.254): 56 data bytes
....  (I start to browse the web and packets start being dropped)

64 bytes from 192.168.2.254: icmp_seq=22 ttl=64 time=2.200 ms
64 bytes from 192.168.2.254: icmp_seq=24 ttl=64 time=2.228 ms
64 bytes from 192.168.2.254: icmp_seq=26 ttl=64 time=2.625 ms
64 bytes from 192.168.2.254: icmp_seq=29 ttl=64 time=4.057 ms
64 bytes from 192.168.2.254: icmp_seq=30 ttl=64 time=2.592 ms
64 bytes from 192.168.2.254: icmp_seq=35 ttl=64 time=2.605 ms
64 bytes from 192.168.2.254: icmp_seq=37 ttl=64 time=2.649 ms
64 bytes from 192.168.2.254: icmp_seq=45 ttl=64 time=2.261 ms
64 bytes from 192.168.2.254: icmp_seq=46 ttl=64 time=2.333 ms
64 bytes from 192.168.2.254: icmp_seq=47 ttl=64 time=2.471 ms
64 bytes from 192.168.2.254: icmp_seq=48 ttl=64 time=2.217 ms

.... (then gets worse..)

64 bytes from 192.168.2.254: icmp_seq=60 ttl=64 time=2.774 ms
64 bytes from 192.168.2.254: icmp_seq=61 ttl=64 time=118.793 ms
64 bytes from 192.168.2.254: icmp_seq=62 ttl=64 time=2.616 ms
64 bytes from 192.168.2.254: icmp_seq=63 ttl=64 time=164.715 ms
64 bytes from 192.168.2.254: icmp_seq=64 ttl=64 time=2.723 ms
64 bytes from 192.168.2.254: icmp_seq=65 ttl=64 time=8.166 ms
64 bytes from 192.168.2.254: icmp_seq=66 ttl=64 time=135.772 ms
64 bytes from 192.168.2.254: icmp_seq=67 ttl=64 time=2.651 ms
64 bytes from 192.168.2.254: icmp_seq=68 ttl=64 time=183.854 ms
64 bytes from 192.168.2.254: icmp_seq=69 ttl=64 time=2.771 ms
64 bytes from 192.168.2.254: icmp_seq=70 ttl=64 time=129.143 ms
64 bytes from 192.168.2.254: icmp_seq=71 ttl=64 time=2.619 ms
64 bytes from 192.168.2.254: icmp_seq=72 ttl=64 time=2.768 ms
64 bytes from 192.168.2.254: icmp_seq=73 ttl=64 time=2.544 ms
^C
--- 192.168.2.254 ping statistics ---
74 packets transmitted, 48 packets received, 35% packet loss
round-trip min/avg/max/stddev = 2.137/17.837/183.854/44.555 ms

There have been some strange log messages related to wifi0 also:

firewall:/var/log# grep wifi0 syslog
Oct  1 23:23:58 firewall kernel: wifi0: 00:16:cb:b9:71:e9 auth_cb -  
alg=0 trans#=2 status=0 - STA authenticated
Oct  1 23:23:58 firewall kernel: wifi0: 00:16:cb:b9:71:e9 assoc_cb -  
STA associated
Oct  1 23:24:01 firewall kernel: wifi0: STA 00:16:cb:b9:71:e9 TX rate  
lowered to 55
Oct  1 23:24:02 firewall kernel: wifi0: STA 00:16:cb:b9:71:e9 TX rate  
lowered to 20
Oct  1 23:30:16 firewall kernel: wifi0: STA 00:16:cb:b9:71:e9 TX rate  
raised to 55
Oct  1 23:31:03 firewall kernel: wifi0: STA 00:16:cb:b9:71:e9 TX rate  
lowered to 20

The above TX rate lowered and raised messages seem only to happen  
with the Airport Extreme cards??

Regards,

Michael