Date: Sat, 3 May 2008 16:59:06 +0200 From: Petar Bogdanovic <petar@smokva.net> To: freebsd-net@freebsd.org Subject: Re: authentication timeouts with ath(4) in hostap mode Message-ID: <20080503145906.GA3417@pintail.smokva.net> In-Reply-To: <481BB0E5.8000803@freebsd.org> References: <20080502093655.GA3535@pintail.smokva.net> <481BB0E5.8000803@freebsd.org>
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On Fri, May 02, 2008 at 05:25:09PM -0700, Sam Leffler wrote: > Petar Bogdanovic wrote: >> Hi, >> >> I'm using an alix2c0 board with two winstron CM9 ath(4)-cards and >> FreeBSD 7: >> >> ifconfig ath0 (...) mediaopt hostap mode 11a channel 36 ssid sn.a -bgscan >> ifconfig ath1 (...) mediaopt hostap mode 11g channel 11 ssid sn.g -bgscan >> >> >> When I try to raise the traffic (i.e. dd | ssh AP dd) my Linux >> wpa_supplicant drops the connection and has to reassociate. This however >> does not work immediately; The supplicant fails a few times before >> reconnecting: >> >> <2>CTRL-EVENT-CONNECTED - Connection to 00:0b:0b:06:0d:09 completed (reauth) [id=0 id_str=] >> <2>CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys >> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320 MHz) >> <2>Authentication with 00:0b:0b:06:0d:09 timed out. >> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320 MHz) >> <2>Authentication with 00:0b:0b:06:0d:09 timed out. >> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320 MHz) >> <2>Authentication with 00:0b:0b:06:0d:09 timed out. >> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320 MHz) >> <2>Authentication with 00:0b:0b:06:0d:09 timed out. >> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320 MHz) >> <2>Authentication with 00:0b:0b:06:0d:09 timed out. >> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320 MHz) >> <2>Authentication with 00:0b:0b:06:0d:09 timed out. >> <2>Trying to associate with 00:0b:0b:06:0d:09 (SSID='sn.a' freq=5320 MHz) >> <2>Associated with 00:0b:0b:06:0d:09 >> <2>WPA: Key negotiation completed with 00:0b:0b:06:0d:09 [PTK=CCMP GTK=CCMP] >> <2>CTRL-EVENT-CONNECTED - Connection to 00:0b:0b:06:0d:09 completed (reauth) [id=0 id_str=] >> >> >> This happens more on the 11a than on the 11g network. When I'm next to >> the AP, the timeouts are almost gone but they still happen. (My laptop >> is just one room away from the AP). Here is the athstats-output of ath0 >> (11a): >> >> # ./athstats -i ath0 >> 481546 data frames received >> 330669 data frames transmit >> 13395 tx frames with an alternate rate >> 78558 long on-chip tx retries >> 1431 tx failed 'cuz too many retries >> 36M current transmit rate >> 78 tx management frames >> 3 tx frames discarded prior to association >> 45 tx frames with no ack marked >> 2894 rx failed 'cuz of bad CRC >> 2 rx failed 'cuz decryption >> 92711 rx failed 'cuz of PHY err >> 92708 OFDM timing >> 3 OFDM restart >> 318332 beacons transmitted >> 1111 periodic calibrations >> 2 rfgain value change >> 22 rssi of last ack >> 23 avg recv rssi >> -96 rx noise floor >> 2530 switched default/rx antenna >> Antenna profile: >> [1] tx 173364 rx 123068 >> [2] tx 155874 rx 358671 > > So the obvious question is whether your system config has enough isolation > of the radios for them not to impact each other? Do you mean the isolation between the four (2x11a/2x11g) pigtail cables inside the box? Well, when I take a look at the product sheet: http://pcengines.ch/pigsma.htm it looks that the cables aren't shielded at all. Is this question based on the high PHY error rate? This value is steadily growing on both interfaces -- here are the stats of ath1 (11g): # ./athstats -i ath1 938627 data frames received 1727374 data frames transmit 7883 tx frames with an alternate rate 93209 long on-chip tx retries 2871 tx failed 'cuz too many retries 11M current transmit rate 7127 tx management frames 3 tx frames discarded prior to association 1998 tx frames with no ack marked 1718962 tx frames with short preamble 4363254 rx failed 'cuz of bad CRC 5115659 rx failed 'cuz of PHY err 23579 OFDM timing 5092074 CCK timing 6 CCK restart 713605 beacons transmitted 2460 periodic calibrations 2 rfgain value change 18 rssi of last ack 21 avg recv rssi -96 rx noise floor 102 cabq frames transmitted 26685 switched default/rx antenna Antenna profile: [1] tx 1416324 rx 1017871 [2] tx 308291 rx 2758 I assume this one is related to the high AP-density -- there are about 13-15 11g networks available in our living room. Yesterday I tried the same tests with a freesbie client (FreeBSD 6.2) and a Windows client. The link of the former was totally stable. No disconnects on 11a and transfer rates around 2.7MB/s. 11g was stable and fast (3.3MB/s) too but the ALIX board suddenly rebooted. (this seems to be an other issue) The Windows client was stable and fast (3MB/s) on 11a but slow and lossy due disconnects on 11g. After all I also booted an old Debian based live-cd with an old kernel, old madwifi drivers and wpa_supplicant 4.9. It started to disconnect again (both modes). > Does turning off one radio give you stable operation? I just did a `ifconfig ath1 txpower 0' but no luck. Is there a ifconfig way to completely turn off the radio or do I have to unplug ath1 to be sure? > Have you verified the packets are present in the air? Have you traced > packets and/or phy errors around the time of the problem? How do I do that? > Have you tried different channels? Yes. On 11a it makes no difference (I tried 36 and 64). On 11g I get the best result on channel 11. This makes sense, since a lot of the other networks operate on channel 1 or 6. > you tried different boards? Unfortunately, I only have one ALIX board. But maybe I'll try a generic PC just for the sake of certainty. Sorry for the lack of information in my first mail and thanks for your answer, Petar
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