| View previous topic :: View next topic |
| Author |
Message |
Adel Ahmed
Veteran
Joined: 21 Sep 2012
Posts: 1616
|
 Posted: Thu Apr 24, 2014 6:59 am Post subject: wlan0 stuck at 11MB/s rate |
 |
|
I'm using a :
09:00.0 Network controller: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter (rev 01)
#iwconfig
wlan0 IEEE 802.11bgn ESSID:"wifi"
Mode:Managed Frequency:2.462 GHz Access Point: D8:5D:4C:C6:3A:1D
Bit Rate=11 Mb/s Tx-Power=19 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Encryption key:off
Power Management:off
Link Quality=70/70 Signal level=51 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:29 Invalid misc:545 Missed beacon:0
If I set the rate manually to 54Mb/s I get many Tx excessive retries and very degraded network performance, I'm not sure what sets this card to this rate
here are some config lines in my laptop-mode tools:
CONTROL_IPW_POWER="0"
CONTROL_IWL_POWER="0"
CONTROL_WIRELESS_POWER_SAVING="disabled"
thanks |
|
| Back to top |
|
 |
tox2ik
n00b
Joined: 15 Jun 2009
Posts: 15
|
| Posted: Sat Apr 26, 2014 8:20 pm Post subject: |
|
|
Which driver are you using?
According to http://www.broadcom.com/docs/linux_sta/README.txt (net-wireless/broadcom-sta), your card is supported. So is mine (4360), but I only get 54 Mbit/s. Perhaps the driver is just bad? Have you tried the card under another OS (e.g Knoppinx, MS Windows) and found any differences in performance? |
|
| Back to top |
|
|
khayyam
Watchman
Joined: 07 Jun 2012
Posts: 6227
Location: Room 101
|
| Posted: Sun Apr 27, 2014 1:35 am Post subject: |
|
|
| tox2ik wrote: | | [...] but I only get 54 Mbit/s. Perhaps the driver is just bad? |
tox2ik ... it has very little to do with the driver, its the link layer protocol. How fast is TCP? You might have a gigabit ethernet card, but TCP will be slower than UDP, why is that? TCP is used where high reliability is required, and transmission time is less critical, to aquire reliability it adjusts itself to the link quality and (if need be) lowers the transmission speed based on how reliably the packets are transmitted. The same is happening in the above, the bitrate is adjusted (dynamically) according to link level transmission, higher bitrates equate to frames being more tightly packed ... and so the greater potencial for loss ... and the bitrate lowered to compensate. So, speed isn't everything ...
best ... khay |
|
| Back to top |
|
|
Adel Ahmed
Veteran
Joined: 21 Sep 2012
Posts: 1616
|
| Posted: Sun Apr 27, 2014 7:15 pm Post subject: |
|
|
| thanks khayyam, I changed the wifi channel to one that isn't being used by my neighbours and now the bit rate goes up to 54Mb/s when I'm using my nfs server |
|
| Back to top |
|
|
|
Networking & Security
