[Trac #841] reproducible loss of wireless association
Zarro Boogs per Child
bugtracker at laptop.org
Thu Feb 1 11:07:44 EST 2007
#841: reproducible loss of wireless association
----------------------+-----------------------------------------------------
Reporter: Quozl | Owner: marcelo
Type: defect | Status: assigned
Priority: blocker | Milestone: BTest-3
Component: wireless | Resolution:
Keywords: |
----------------------+-----------------------------------------------------
Comment (by marcelo):
Thanks for the log.
The problem is not related to the low signal strength issue I was saw in
the past.
What happpens is that association is lost suddenly. During this window,
its possible to verify
that the wireless device can't communicate with the AP since the periodic
scanning performed by
NM gives no results. Analyzing the log file, we see that the first
instance of the problem happens during the window between lines 27155 and
28263 of your log file:
{{{
[marcelo at dmt libertas]$ cat process-signal.sh
grep -n Signal quozl-2-var-log-messages-841.txt | while read i ; do
SIGNAL=`echo $i | cut -f 2 -d "="`
DBM=`/home/marcelo/wireless/to-dbm $SIGNAL`
LINE=`echo $i | cut -f 1 -d ":"`
echo $SIGNAL=$DBM \($LINE\)
done
0xcc=-52 (24826)
0xcd=-51 (26334)
0xcd=-51 (27155)
0x0=-0 (27246)
0xd0=-48 (28263)
0xd0=-48 (29062)
0xce=-50 (29715)
0x0=-0 (29806)
0xce=-50 (30823)
0xce=-50 (31459)
0xce=-50 (32287)
0x0=-0 (32391)
0xcc=-52 (33390)
}}}
Closer look at the scan response during such window:
{{{
[marcelo at dmt libertas]$ egrep -n "\[ 1289.|\[ 1290" quozl-2-var-log-
messages-841.txt | grep SCAN_RESP
26813:Jan 31 21:18:33 localhost kernel: [ 1289.155856] SCAN_RESP:
BSSDescriptSize 74
26814:Jan 31 21:18:33 localhost kernel: [ 1289.155884] SCAN_RESP: returned
1 AP before parsing
26815:Jan 31 21:18:33 localhost kernel: [ 1289.155917] SCAN_RESP:
tlvBufSize = 12
26821:Jan 31 21:18:33 localhost kernel: [ 1289.156666] Ssid:
quozl.linux.org.au<6>SCAN_RESP: BSSID = 00:13:10:44:5f:ad
26822:Jan 31 21:18:33 localhost kernel: [ 1289.156743] SCAN_RESP: Scanned
1 APs, 1 valid, 1 total
26862:Jan 31 21:18:33 localhost kernel: [ 1289.274835] SCAN_RESP:
BSSDescriptSize 0
26863:Jan 31 21:18:33 localhost kernel: [ 1289.274866] SCAN_RESP: returned
0 AP before parsing
26864:Jan 31 21:18:33 localhost kernel: [ 1289.274896] SCAN_RESP:
tlvBufSize = 0
26865:Jan 31 21:18:33 localhost kernel: [ 1289.274956] SCAN_RESP: Scanned
0 APs, 0 valid, 1 total
26905:Jan 31 21:18:34 localhost kernel: [ 1289.503205] SCAN_RESP:
BSSDescriptSize 0
26906:Jan 31 21:18:34 localhost kernel: [ 1289.503237] SCAN_RESP: returned
0 AP before parsing
26907:Jan 31 21:18:34 localhost kernel: [ 1289.503267] SCAN_RESP:
tlvBufSize = 0
26908:Jan 31 21:18:34 localhost kernel: [ 1289.503327] SCAN_RESP: Scanned
0 APs, 0 valid, 1 total
27205:Jan 31 21:18:34 localhost kernel: [ 1289.677205] SCAN_RESP:
BSSDescriptSize 0
27206:Jan 31 21:18:34 localhost kernel: [ 1289.677236] SCAN_RESP: returned
0 AP before parsing
27207:Jan 31 21:18:34 localhost kernel: [ 1289.677266] SCAN_RESP:
tlvBufSize = 0
27208:Jan 31 21:18:34 localhost kernel: [ 1289.677324] SCAN_RESP: Scanned
0 APs, 0 valid, 0 total
27326:Jan 31 21:18:34 localhost kernel: [ 1290.123073] SCAN_RESP:
BSSDescriptSize 0
27327:Jan 31 21:18:34 localhost kernel: [ 1290.123103] SCAN_RESP: returned
0 AP before parsing
27328:Jan 31 21:18:34 localhost kernel: [ 1290.123134] SCAN_RESP:
tlvBufSize = 0
27329:Jan 31 21:18:34 localhost kernel: [ 1290.123192] SCAN_RESP: Scanned
0 APs, 0 valid, 0 total
27425:Jan 31 21:18:34 localhost kernel: [ 1290.242689] SCAN_RESP:
BSSDescriptSize 0
27426:Jan 31 21:18:34 localhost kernel: [ 1290.242720] SCAN_RESP: returned
0 AP before parsing
27427:Jan 31 21:18:34 localhost kernel: [ 1290.242750] SCAN_RESP:
tlvBufSize = 0
27428:Jan 31 21:18:34 localhost kernel: [ 1290.242809] SCAN_RESP: Scanned
0 APs, 0 valid, 0 total
27468:Jan 31 21:18:35 localhost kernel: [ 1290.689316] SCAN_RESP:
BSSDescriptSize 74
27469:Jan 31 21:18:35 localhost kernel: [ 1290.689345] SCAN_RESP: returned
1 AP before parsing
27470:Jan 31 21:18:35 localhost kernel: [ 1290.689378] SCAN_RESP:
tlvBufSize = 12
27476:Jan 31 21:18:35 localhost kernel: [ 1290.690130] Ssid:
quozl.linux.org.au<6>SCAN_RESP: BSSID = 00:13:10:44:5f:ad
27477:Jan 31 21:18:35 localhost kernel: [ 1290.690208] SCAN_RESP: Scanned
1 APs, 1 valid, 1 total
27517:Jan 31 21:18:35 localhost kernel: [ 1290.808295] SCAN_RESP:
BSSDescriptSize 0
27518:Jan 31 21:18:35 localhost kernel: [ 1290.808326] SCAN_RESP: returned
0 AP before parsing
27519:Jan 31 21:18:35 localhost kernel: [ 1290.808356] SCAN_RESP:
tlvBufSize = 0
27520:Jan 31 21:18:35 localhost kernel: [ 1290.808416] SCAN_RESP: Scanned
0 APs, 0 valid, 1 total
}}}
Quozl, one suspicion is that NM's periodic scanning triggers the lack of
AP visibility issue.
Can you please try to reproduce the problem without NM running?
In the meantime, I'll look into finding a similar access point with
OpenWRT to reproduce the problem.
--
Ticket URL: <http://dev.laptop.org/ticket/841#comment:15>
One Laptop Per Child <http://laptop.org/>
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