Timing and fragmentation

Jouni Malinen jkmaline at cc.hut.fi
Fri Oct 10 23:03:48 EDT 2003


On Fri, Oct 10, 2003 at 09:38:07PM -0000, Jerry wrote:

>    Now, can fragmentation help any for the packet loss?   It doesnt appear
> that the fragmentation command (iwconfig wlan0 frag xxx) works... i have
> 10/3/03 CVS.

In some cases, fragmentation can help because it limits the length of
the transmitted frames and requires acknowledgement for each fragment.

'iwconfig wlan0 frag xxx' is supposed to work or at least I'm not aware
of any issues with it. Please provide some more details (firmware
versions, exact command used, possible error messages). Please also
verify with utils/hostap_diag whether the configuration value was
actually changed. For example:

# iwconfig wlan0 fragm 512
# iwconfig wlan0
wlan0     IEEE 802.11b  ESSID:"test"
          Mode:Managed  Frequency:2.462GHz  Access Point: 00:11:22:33:44:55
          Bit Rate:11Mb/s   Sensitivity=1/3
          Retry min limit:8   RTS thr:off   Fragment thr=512 B
          Encryption key:off

# ./hostap_diag wlan0 -r | grep FC82
FC82=FRAGMENTATIONTHRESHOLD=512

-- 
Jouni Malinen                                            PGP id EFC895FA



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