Testing protocol stack with OsmocomBB (cheap way)

weberbe at ee.ethz.ch weberbe at ee.ethz.ch
Sun Jun 5 07:22:17 UTC 2011


Hi Drasko

I am not so sure why you are not succeeding in recording anything in  
wireshark. From what I have seen from your other posts you are doing  
it the right way. Well, here is what should happen anyway:

1) The phone measures the receive power of all the channels it can  
handle unless you specified to stick to a specific channel in the  
mobile application.
2) The channels with the highest receive power are most likely to be  
beacon carriers. So the phone will try to synchronize in frequency and  
time to such a carrier. The synchronization in time will retrieve the  
current frame number und the BSIC of the base station.
3) If the synchronization is successfull, the phone will monitor  
various logical channels on the beacon carrier: The broadcast control  
channel (BCCH), common control channel (CCCH) and the paging channel  
(PCH) (and maybe some more, I am not so sure). The packets received on  
these channels will be dumped on wireshark or whatever you are using.  
As soon as all system information (SI) messages from BCCH are decoded,  
the phone can camp on this cell.

In order to achieve this you need osmocon, mobile and wireshark to be running.

Hope this helps
Ben

Quoting "Drasko DRASKOVIC" <drasko.draskovic at gmail.com>:

> On Mon, May 30, 2011 at 8:56 AM,  <weberbe at ee.ethz.ch> wrote:
>> As this is all you want just use the signal from any commercial BTS in your
>> area. OsmocomBB is able to capture System Information Messages and Paging
>> Requests and forward the content to Wireshark.
>
> Hi weberbe,
> can you explain in some more details how this can be done ?
>
> So far I did not succeed to attach to any cell, not to get some  
> packets from it.
>
> At which moment can we observe the packets which are coming :
> 1) During the initial measurements or
> 2) Only after we attach to a cell
>
> What should be set up, what applications run and in which order to
> obtain some packet logging in Wireshark.
>
> I am running master branch - so, no SIM working.
>
> Best regards,
> Drasko
>







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