# wlan0 stuck at 11MB/s rate

## Adel Ahmed

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

----------

## tox2ik

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?

----------

## khayyam

 *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

----------

## Adel Ahmed

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

----------

