Re: [ath5k-devel] Ath5k Packet loss
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 JitterLost/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 ms1/ 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 ___ ath5k-devel mailing list ath5k-devel@lists.ath5k.org https://lists.ath5k.org/mailman/listinfo/ath5k-devel -- * 株式会社 シンクチューブ 海藻 敬之 tka...@thinktube.com 〒658-0032 神戸市東灘区向洋町中６－９ KFMビル 4E-10 Phone: 078-857-8390 Fax: 078-857-8389 www.thinktube.com ___ ath5k-devel mailing list ath5k-devel@lists.ath5k.org https://lists.ath5k.org/mailman/listinfo/ath5k-devel
Re: [ath5k-devel] Ath5k Packet loss
If the datarate is 6Mbps, and Iperf is trying to send 6Mbps, it is impossible to have no loss, because datarate != throughput. You have ACKs, and maybe some backoff and difs and sifs, etc. So you are going to drop packets, because with the channel configured this way it is not possible to send at 6Mbps (iperf). And dont forget the overhead of the packets, of course. If you use 12Mbps (datarate) or more, i guess you wont have problems. 2009/9/22 Nick Kossifidis mickfl...@gmail.com: 2009/9/22 Qasim Javed qas...@gmail.com: Hi, 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 Try reducing tx power and see how it goes... -- GPG ID: 0xD21DB2DB As you read this post global entropy rises. Have Fun ;-) Nick ___ ath5k-devel mailing list ath5k-devel@lists.ath5k.org https://lists.ath5k.org/mailman/listinfo/ath5k-devel -- Henrique Marks henriquema...@gmail.com hma...@parks.com.br http://henriquemarks.blogspot.com http://henriquemarks.googlepages.com tel: 30237882 cel: 9838-6869 twitter: henriquemarks ___ ath5k-devel mailing list ath5k-devel@lists.ath5k.org https://lists.ath5k.org/mailman/listinfo/ath5k-devel
[ath5k-devel] Ath5k Packet loss
Hi, 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 BandwidthJitter Lost/Total Datagrams [ 3] 0.0-31.0 sec 44.5 KBytes 11.8 Kbits/sec 0.060 ms1/ 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 ___ ath5k-devel mailing list ath5k-devel@lists.ath5k.org https://lists.ath5k.org/mailman/listinfo/ath5k-devel
