On Thu, 24 Jul 2008, Kalle Valo wrote: (packets from N810 captured with airodump-ng show as malformed) > Usually missing FCS causes this. There's a setting in Wireshark under > IEEE 802.11 to enable and disable FCS calculation. Try reverting that > option. Yes. Edit/Preferences/Protocols/IEEE 802.11. Also lets me set WEP keys. Not sure I have that working right, but I turned off WEP/WPA to debug, anyway. I was able to get the IBM laptop into monitor mode using the madwifi instructions (thanks) - airodump did not do it as it does on the tablet. # wlanconfig ath0 destroy # wlanconfig ath0 create wlandev wifi0 wlanmode monitor # ifconfig ath0 up # echo '801' > /proc/sys/net/ath0/dev_type then I could use tcpdump or ethereal/wireshark. If I don't suppress prism headers then I can't refilter with "tcpdump wlan host <node>" which makes it hard to sift through the traffic at work. I have placed some capture data on my server at http://andrew.triumf.ca/reqauth/PSM/ (password test/test to keep out robots and the clueless) I may be being dumb, but I can't see a problem. I can see the tablet doing a power-save poll and saying it is going to sleep after the transactions, and the more-data bit appears cleared. I can see the DTIM bits being set in the beacon before the data transactions and cleared afterwords. There is a lot more traffic at work (duh), including lots of ip broadcast traffic on a VLAN connected to our wired LAN. But that's on a different SSID. We recently created a separate VLAN & SSID with encryption on, which is what I normally use on the tablet, but here I used our visitor SSID. These don't see the ip broadcasts from the wired LAN, but in any case as I understand it these should not make a substantial difference in PS mode. A battery graph is at http://andrew.triumf.ca/reqauth/PSM/batt.use2.gif I may be able to get a spare Proxim AP to take home. There's a limit on what I can mess with on our production WLAN :-7, and I'd have a less noisy environment. I'm not sure what I can tell Proxim. Send them the capture files, I guess. Setting the AP to closed mode made no difference. notes: If I want to see ping broadcasts, I can do echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts I wondered whether setting /proc/sys/net/ipv4/tcp_frto helps, as per kernel ip-sysctl.txt ("particularly beneficial in wireless environments") Not for the power, just for transmission errors. I thought that unicast data was buffered till the next beacon in PS mode, with broadcast/multicast buffered till the next DTIM interval, but at least on my Linksys router it looks like unicast is buffered till DTIM too. It lets me adjust both the beacon interval and DTIM; the Proxim allows only DTIM. Defaults are 100ms and 1x. If the delay (beacon interval x DTIM) exceeds about 10 seconds, the tablet won't respond to incoming data. My desktop says "network not reachable". I thought that was a tunable parameter but the only one I found was a SYN timeout at 60x. If the tablet is in power-save mode, doing "iwconfig wlan0 power off" will momentarily revert it to non-PS, and incoming data is received. Outgoing data is unaffected. Doing a broadcast ping was interesting with DTIM > the ping interval; wired stations respond every second but the wireless ones are bunched up in a group. As expected; it just looks weird. -- Andrew Daviel, TRIUMF, Canada _______________________________________________ maemo-users mailing list maemo-users@xxxxxxxxx https://lists.maemo.org/mailman/listinfo/maemo-users
