ORBIT-USER: BSSID/CELL issues in ad-hoc mode

[Einar Vollset]

How quickly are you bringing up each node? I had the same problems  
with only 5 nodes on the grid
when configuring them all at the same time, like so:

for x in `echo $xcoords`
do
for y in `echo $ycoords`
do
   ssh root at node$x-$y modprobe ath_pci &
   ssh root at node$x-$y ifconfig ath0 down  &
   ssh root at node$x-$y wlanconfig ath0 destroy &
   ssh root at node$x-$y wlanconfig ath0 create wlandev wifi0 wlanmode  
adhoc &
   ssh root at node$x-$y iwconfig ath0 essid einarnet &
   ssh root at node$x-$y iwconfig ath0 rate 5.5M &
   ssh root at node$x-$y ifconfig ath0 192.168.$x.$y up &
   echo "Configured node$x-$y"
done
done

..but bringing them up one by one worked (so far anyways):

for x in `echo $xcoords`
do
for y in `echo $ycoords`
do
   ssh root at node$x-$y modprobe ath_pci &&
   ssh root at node$x-$y ifconfig ath0 down  &&
   ssh root at node$x-$y wlanconfig ath0 destroy &&
   ssh root at node$x-$y wlanconfig ath0 create wlandev wifi0 wlanmode  
adhoc &&
   ssh root at node$x-$y iwconfig ath0 essid einarnet &&
   ssh root at node$x-$y iwconfig ath0 rate 5.5M &&
   ssh root at node$x-$y ifconfig ath0 192.168.$x.$y up &&
   echo "Configured node$x-$y"
done
done

..This is with madwifi-0.9.2 (which may or may not be what's on by  
default. Easy to install though)


The only way I found to set BSSIDs (this is for madwifi drivers), is  
with the devices in AP mode:
iwconfig ath0 ap 00:00:00:00:00:00, etc. Perhaps you could do  
something like setup one AP, bring up everyone
else as a STA, Destroy the AP and then switch to Ad-Hoc? Pretty  
hacky, and probably wouldn't work..

As an aside - it's interesting how little google knows about this -  
suggests that large scale ad-hoc network
experimentation is rather uncommon.. :-)


p.s. I'd like to take a look at your tools if you wouldn't mind?

Cheers,

Einar




On Aug 23, 2006, at 5:22 PM, Sachin Ganu wrote:

> Hi Chris,
> I believe this functionality for Atheros is embedded in the HAL
> somewhere. In other words, this now gets us into the wireless driver
> domain (outside of ORBIT's control, unfortunately :-)
>
> If you are using ad-hoc mode, depending on how it is implemented, the
> responsibility of cell formation and maintenance is distributed and
> clearly there are some synchronization problems when the number of
> nodes goes up.. Hence, some of them start to create their own BSSID's
> for the same ESSID.
>
> .no solution yet...hence only commiserations. :-)
>
> -Sachin
>
> On 8/23/06, chris at orderonenetworks.com <chris at orderonenetworks.com>  
> wrote:
>> I'm hoping someone can help.
>>
>> I've got most of the grid fired up and have huge problems with the  
>> radio's
>> coming up with their own CELL/BSSID numbers and then changing them  
>> about
>> every 5 secs or so. This means that I am basically unable to build a
>> network in the grid. Sandbox nodes have no such problems - most  
>> likely
>> this is a size related issue.
>>
>> Is there anyway to manually set the CELL/BSSID, or have the cards  
>> ignore
>> this value so it doesn't matter?
>>
>> Thanks,
>> Chris
>>
>>