Hi,
I am now facing the same (or similar) problem which Qasim reported 3
weeks before.
(In my case, mode is Ad-Hoc rather than STA/AP )
Details are reported below, but in short things have bogged down here
with me
while I am start looking around ath5k_hw_noise_floor_calibration() and
related register settings in reg.h,
<configuration of my network>
-simple 2 nodes :
one is Soekris 4826 with Madwifi-0.9.4 and
the other is Ubiquity RS-Pro with Ath5k (compat-wireless-2009-0820)
- wireless card : SparkLAN 166AG (MAC AR5414) on both nodes
- operation mode : IBSS a d-hoc
< test scenario >
- iperf (UDP) between the PC(A) connected to Soekris 4826 with
Madwifi-0.9.4 and
another PC(B) connected to Ubiquity RS-Pro with Ath5k
(compat-wireless-2009-0820)
- IBSS ad-hoc wireless between Soekris 4826 and Ubiquity RS-Pro
< result >
1. when iperf packets go from PC(B) to PC(A), iperf UDP receiver
showed up to 16Mbps
and loss is 0.0% --> looks so great .
2. change the flow direction and when iperf packets go from PC(A) to
PC(B),
iperf UDP receiver showed following results. (in this case ath5
is receiver side )
(iperf -c x.x.x.x -u -b 12M -t 30 )
- 90% loss (when sender(madwifi) set as "rate 54M fixed")
- 90% loss (when sender(madwifi) set as "rate 48M fixed")
- 1% ~ 3% loss (when sender(madwifi) set as "rate 36M fixed")
- 0.2% ~ 0.7% loss (when sender(madwifi) set as "rate 24M fixed")
- 5%~20% (when sender(madwifi) set as "rate auto")
I added some lines in ath5k_tasklet_rx() for investigating the error
reason
and found huge number of AR5K_RXERR_CRC error happened for
54M and 48Mbps cases.
Why AR5K_RXERR_CRC happened in just one direction ?
I modified AR5K_DEFAULT_ANTENNA from 0 to 1 to
disable antenna diversity , but the iperf results showed no change.
HW (wireless card / Antenna ) itself does not have problem
(verified with 4 or 5 HW sets ), I believe.
Takayuki Kaiso
I have a gentoo system and the latest Ath5k drivers from
compat-wireless. I downloaded them about a week back. I understand
that the tarball is updated daily.
I have three Ubiquiti SRC cards (AR5212). I have configured one of
them as an AP in 802.11a mode using channel 149. The other two are
stations connected to the AP. I fixed the rate to 6Mbps.
I have an iperf server running on the AP which accepts UDP traffic.
One of the stations sends UDP packets at a rate of 6Mbps to the AP.
Because there are no surrounding APs in 802.11a mode, the band is very
quiet. However, I am surprised that I get 2.6% packet loss when I run
the above mentioned experiment. The distance of both stations is no
more than 10 meters from the AP. Also, the txpower for both STAs is 30dbm.
One STA sends UDP packets to the AP at 6Mbps for 30 seconds and the
report that iperf generates is as follows:
[ ID] Interval Transfer Bandwidth
Jitter Lost/Total Datagrams
[ 3] 0.0-30.1 sec 18.3 MBytes 5.11 Mbits/sec 0.301 ms 352/13434
(2.6%)
Considering that there is no activity on this channel except the
beacons of AP and probe requests/responses from the other STA, how can
352 packets get lost?
To make things worse, I tried the above experiment with minimal
bandwidth. Very oddly, the results are as follows:
[ ID] Interval Transfer Bandwidth
Jitter Lost/Total Datagrams
[ 3] 0.0-31.0 sec 44.5 KBytes 11.8 Kbits/sec 0.060 ms 1/ 32
(3.1%)
Why would even a packet get lost at this very slow data rate? I have
repeated the above several times, and it always results in about the
same numbers.
Earlier, I had also noticed that if I ping one STA from the other STA,
about every 10 seconds, the ping response time jumps from 0.8
milliseconds to 25 milliseconds.
I would be really grateful if I can get some feedback fro myou guys on
this so that we can fix whatever is messing things up here.
Thanks,
-Qasim
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